diff --git "a/llmeval-env/lib/python3.10/site-packages/transformers/models/perceiver/modeling_perceiver.py" "b/llmeval-env/lib/python3.10/site-packages/transformers/models/perceiver/modeling_perceiver.py" new file mode 100644--- /dev/null +++ "b/llmeval-env/lib/python3.10/site-packages/transformers/models/perceiver/modeling_perceiver.py" @@ -0,0 +1,3435 @@ +# coding=utf-8 +# Copyright 2021 Deepmind and The HuggingFace Inc. team. All rights reserved. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. +""" PyTorch Perceiver model.""" + +import abc +import math +from dataclasses import dataclass +from functools import reduce +from operator import __add__ +from typing import Any, Callable, Dict, List, Mapping, Optional, Tuple, Union + +import numpy as np +import torch +import torch.utils.checkpoint +from torch import nn +from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss + +from ...activations import ACT2FN +from ...modeling_outputs import BaseModelOutputWithCrossAttentions +from ...modeling_utils import PreTrainedModel +from ...pytorch_utils import apply_chunking_to_forward, find_pruneable_heads_and_indices, meshgrid, prune_linear_layer +from ...utils import ( + ModelOutput, + add_start_docstrings, + add_start_docstrings_to_model_forward, + logging, + replace_return_docstrings, +) +from .configuration_perceiver import PerceiverConfig + + +ModalitySizeType = Mapping[str, int] +PreprocessorOutputType = Tuple[torch.Tensor, Optional[torch.Tensor], torch.Tensor] +PreprocessorType = Callable[..., PreprocessorOutputType] +PostprocessorType = Callable[..., Any] + +logger = logging.get_logger(__name__) + +_CHECKPOINT_FOR_DOC = "deepmind/language-perceiver" +_CONFIG_FOR_DOC = "PerceiverConfig" + + +from ..deprecated._archive_maps import PERCEIVER_PRETRAINED_MODEL_ARCHIVE_LIST # noqa: F401, E402 + + +@dataclass +class PerceiverModelOutput(ModelOutput): + """ + Base class for Perceiver base model's outputs, with potential hidden states, attentions and cross-attentions. + + Args: + logits (`torch.FloatTensor` of shape `(batch_size, num_labels)`): + Classification (or regression if config.num_labels==1) scores (before SoftMax). + last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`): + Sequence of hidden-states at the output of the last layer of the model. + hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. Hidden-states of the model at the output of each layer + plus the initial embedding outputs. + attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. Attentions weights after the attention softmax, used to compute the weighted average in + the self-attention heads. + cross_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. Attentions weights of the decoder's cross-attention layer, after the attention softmax, + used to compute the weighted average in the cross-attention heads. + """ + + logits: torch.FloatTensor = None + last_hidden_state: torch.FloatTensor = None + hidden_states: Optional[Tuple[torch.FloatTensor]] = None + attentions: Optional[Tuple[torch.FloatTensor]] = None + cross_attentions: Optional[Tuple[torch.FloatTensor]] = None + + +@dataclass +class PerceiverDecoderOutput(ModelOutput): + """ + Base class for Perceiver decoder outputs, with potential cross-attentions. + + Args: + logits (`torch.FloatTensor` of shape `(batch_size, num_labels)`): + Output of the basic decoder. + cross_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. Attentions weights of the decoder's cross-attention layer, after the attention softmax, + used to compute the weighted average in the cross-attention heads. + """ + + logits: torch.FloatTensor = None + cross_attentions: Optional[Tuple[torch.FloatTensor]] = None + + +@dataclass +class PerceiverMaskedLMOutput(ModelOutput): + """ + Base class for Perceiver's masked language model outputs. + + Args: + loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `labels` is provided): + Masked language modeling (MLM) loss. + logits (`torch.FloatTensor` of shape `(batch_size, sequence_length, config.vocab_size)`): + Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax). + hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. Hidden-states of the model at the output of each layer + plus the initial embedding outputs. + attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, num_latents, + num_latents)`. Attentions weights after the attention softmax, used to compute the weighted average in the + self-attention heads. + cross_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. Attentions weights of the decoder's cross-attention layer, after the attention softmax, + used to compute the weighted average in the cross-attention heads. + """ + + loss: Optional[torch.FloatTensor] = None + logits: torch.FloatTensor = None + hidden_states: Optional[Tuple[torch.FloatTensor]] = None + attentions: Optional[Tuple[torch.FloatTensor]] = None + cross_attentions: Optional[Tuple[torch.FloatTensor]] = None + + +@dataclass +class PerceiverClassifierOutput(ModelOutput): + """ + Base class for Perceiver's outputs of sequence/image classification models, optical flow and multimodal + autoencoding. + + Args: + loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `labels` is provided): + Classification (or regression if config.num_labels==1) loss. + logits (`torch.FloatTensor` of shape `(batch_size, config.num_labels)`): + Classification (or regression if config.num_labels==1) scores (before SoftMax). + hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. Hidden-states of the model at the output of each layer + plus the initial embedding outputs. + attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. Attentions weights after the attention softmax, used to compute the weighted average in + the self-attention heads. + cross_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. Attentions weights of the decoder's cross-attention layer, after the attention softmax, + used to compute the weighted average in the cross-attention heads. + """ + + loss: Optional[torch.FloatTensor] = None + logits: torch.FloatTensor = None + hidden_states: Optional[Tuple[torch.FloatTensor]] = None + attentions: Optional[Tuple[torch.FloatTensor]] = None + cross_attentions: Optional[Tuple[torch.FloatTensor]] = None + + +class PerceiverEmbeddings(nn.Module): + """Construct the latent embeddings.""" + + def __init__(self, config): + super().__init__() + self.latents = nn.Parameter(torch.randn(config.num_latents, config.d_latents)) + + def forward(self, batch_size: int): + return self.latents.expand(batch_size, -1, -1) # Thanks, Phil Wang + + +class PerceiverSelfAttention(nn.Module): + """Multi-headed {cross, self}-attention. Can be used both in the encoder as well as in the decoder.""" + + def __init__( + self, + config, + is_cross_attention=False, + qk_channels=None, + v_channels=None, + num_heads=1, + q_dim=None, + kv_dim=None, + ): + super().__init__() + self.num_heads = num_heads + # Q and K must have the same number of channels. + # Default to preserving Q's input's shape. + if qk_channels is None: + qk_channels = q_dim + # V's num_channels determines the shape of the output of QKV-attention. + # Default to the same number of channels used in the key-query operation. + if v_channels is None: + v_channels = qk_channels + if qk_channels % num_heads != 0: + raise ValueError(f"qk_channels ({qk_channels}) must be divisible by num_heads ({num_heads}).") + if v_channels % num_heads != 0: + raise ValueError(f"v_channels ({v_channels}) must be divisible by num_heads ({num_heads}).") + + self.qk_channels = qk_channels + self.v_channels = v_channels + self.qk_channels_per_head = self.qk_channels // num_heads + self.v_channels_per_head = self.v_channels // num_heads + + # Layer normalization + self.layernorm1 = nn.LayerNorm(q_dim) + self.layernorm2 = nn.LayerNorm(kv_dim) if is_cross_attention else nn.Identity() + + # Projection matrices + self.query = nn.Linear(q_dim, qk_channels) + self.key = nn.Linear(kv_dim, qk_channels) + self.value = nn.Linear(kv_dim, v_channels) + + self.dropout = nn.Dropout(config.attention_probs_dropout_prob) + + def transpose_for_scores(self, x, channels_per_head): + new_x_shape = x.size()[:-1] + (self.num_heads, channels_per_head) + x = x.view(*new_x_shape) + return x.permute(0, 2, 1, 3) + + def forward( + self, + hidden_states: torch.Tensor, + attention_mask: Optional[torch.FloatTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + inputs: Optional[torch.FloatTensor] = None, + inputs_mask: Optional[torch.FloatTensor] = None, + output_attentions: Optional[bool] = False, + ) -> Tuple[torch.Tensor]: + hidden_states = self.layernorm1(hidden_states) + inputs = self.layernorm2(inputs) + + # Project queries, keys and values to a common feature dimension. If this is instantiated as a cross-attention module, + # the keys and values come from the inputs; the attention mask needs to be such that the inputs's non-relevant tokens are not attended to. + is_cross_attention = inputs is not None + queries = self.query(hidden_states) + + if is_cross_attention: + keys = self.key(inputs) + values = self.value(inputs) + attention_mask = inputs_mask + else: + keys = self.key(hidden_states) + values = self.value(hidden_states) + + # Reshape channels for multi-head attention. + # We reshape from (batch_size, time, channels) to (batch_size, num_heads, time, channels per head) + queries = self.transpose_for_scores(queries, self.qk_channels_per_head) + keys = self.transpose_for_scores(keys, self.qk_channels_per_head) + values = self.transpose_for_scores(values, self.v_channels_per_head) + + # Take the dot product between the queries and keys to get the raw attention scores. + attention_scores = torch.matmul(queries, keys.transpose(-1, -2)) + + batch_size, num_heads, seq_len, q_head_dim = queries.shape + _, _, _, v_head_dim = values.shape + hiddens = self.num_heads * v_head_dim + + attention_scores = attention_scores / math.sqrt(q_head_dim) + + if attention_mask is not None: + # Apply the attention mask (precomputed for all layers in PerceiverModel forward() function) + attention_scores = attention_scores + attention_mask + + # Normalize the attention scores to probabilities. + attention_probs = nn.Softmax(dim=-1)(attention_scores) + + # This is actually dropping out entire tokens to attend to, which might + # seem a bit unusual, but is taken from the original Transformer paper. + attention_probs = self.dropout(attention_probs) + + # Mask heads if we want to + if head_mask is not None: + attention_probs = attention_probs * head_mask + + context_layer = torch.matmul(attention_probs, values) + + context_layer = context_layer.permute(0, 2, 1, 3).contiguous() + new_context_layer_shape = context_layer.size()[:-2] + (hiddens,) + context_layer = context_layer.view(*new_context_layer_shape) + + outputs = (context_layer, attention_probs) if output_attentions else (context_layer,) + + return outputs + + +class PerceiverSelfOutput(nn.Module): + def __init__(self, config, input_channels, output_channels): + super().__init__() + self.dense = nn.Linear(input_channels, output_channels) + + def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: + hidden_states = self.dense(hidden_states) + return hidden_states + + +class PerceiverAttention(nn.Module): + """Attention module, including a dense block.""" + + def __init__( + self, + config, + is_cross_attention=False, + qk_channels=None, + v_channels=None, + num_heads=1, + q_dim=None, + kv_dim=None, + use_query_residual=True, + ): + super().__init__() + # MultiHead attention + if is_cross_attention and qk_channels is None: + if config.cross_attention_shape_for_attention == "q": + qk_channels = q_dim + elif config.cross_attention_shape_for_attention == "kv": + qk_channels = kv_dim + else: + raise ValueError( + f"Unknown value {config.cross_attention_shape_for_attention} for " + "cross_attention_shape_for_attention." + ) + else: + if qk_channels is None: + qk_channels = q_dim + if v_channels is None: + v_channels = qk_channels + self.self = PerceiverSelfAttention( + config, + is_cross_attention=is_cross_attention, + qk_channels=qk_channels, + v_channels=v_channels, + num_heads=num_heads, + q_dim=q_dim, + kv_dim=kv_dim, + ) + # dense block + output_channels = None + if is_cross_attention: + output_channels = q_dim + else: + if output_channels is None: + output_channels = v_channels + self.output = PerceiverSelfOutput(config, input_channels=self.self.v_channels, output_channels=output_channels) + self.use_query_residual = use_query_residual + self.pruned_heads = set() + + def prune_heads(self, heads): + if len(heads) == 0: + return + heads, index = find_pruneable_heads_and_indices( + heads, self.self.num_attention_heads, self.self.attention_head_size, self.pruned_heads + ) + + # Prune linear layers + self.self.query = prune_linear_layer(self.self.query, index) + self.self.key = prune_linear_layer(self.self.key, index) + self.self.value = prune_linear_layer(self.self.value, index) + self.output.dense = prune_linear_layer(self.output.dense, index, dim=1) + + # Update hyper params and store pruned heads + self.self.num_attention_heads = self.self.num_attention_heads - len(heads) + self.self.all_head_size = self.self.attention_head_size * self.self.num_attention_heads + self.pruned_heads = self.pruned_heads.union(heads) + + def forward( + self, + hidden_states: torch.Tensor, + attention_mask: Optional[torch.FloatTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + inputs: Optional[torch.FloatTensor] = None, + inputs_mask: Optional[torch.FloatTensor] = None, + output_attentions: Optional[bool] = False, + ) -> Tuple[torch.Tensor]: + self_outputs = self.self( + hidden_states, + attention_mask, + head_mask, + inputs, + inputs_mask, + output_attentions, + ) + + # Output projection + attention_output = self.output(self_outputs[0]) + + # Optionally include a residual to the original queries. + # Consider omitting the residual if the semantics of query and output + # are different, e.g. if queries are positions and outputs are pixels. + if self.use_query_residual: + attention_output = attention_output + hidden_states + + outputs = (attention_output,) + self_outputs[1:] # add attentions if we output them + return outputs + + +class PerceiverMLP(nn.Module): + """A Transformer-style dense module to follow attention.""" + + def __init__(self, config, input_size, widening_factor): + super().__init__() + self.dense1 = nn.Linear(input_size, widening_factor * input_size) + if isinstance(config.hidden_act, str): + self.intermediate_act_fn = ACT2FN[config.hidden_act] + else: + self.intermediate_act_fn = config.hidden_act + self.dense2 = nn.Linear(widening_factor * input_size, input_size) + + def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: + hidden_states = self.dense1(hidden_states) + hidden_states = self.intermediate_act_fn(hidden_states) + hidden_states = self.dense2(hidden_states) + return hidden_states + + +class PerceiverLayer(nn.Module): + def __init__( + self, + config, + is_cross_attention=False, + qk_channels=None, + v_channels=None, + num_heads=1, + q_dim=None, + kv_dim=None, + widening_factor=4, + use_query_residual=True, + ): + super().__init__() + self.chunk_size_feed_forward = config.chunk_size_feed_forward + self.seq_len_dim = 1 + self.attention = PerceiverAttention( + config, + is_cross_attention=is_cross_attention, + qk_channels=qk_channels, + v_channels=v_channels, + num_heads=num_heads, + q_dim=q_dim, + kv_dim=kv_dim, + use_query_residual=use_query_residual, + ) + self.layernorm = nn.LayerNorm(q_dim) + self.mlp = PerceiverMLP(config, input_size=q_dim, widening_factor=widening_factor) + + def forward( + self, + hidden_states: torch.Tensor, + attention_mask: Optional[torch.FloatTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + inputs: Optional[torch.FloatTensor] = None, + inputs_mask: Optional[torch.FloatTensor] = None, + output_attentions: Optional[bool] = False, + ) -> Tuple[torch.Tensor]: + attention_outputs = self.attention( + hidden_states, + attention_mask, + head_mask, + inputs, + inputs_mask, + output_attentions, + ) + attention_output = attention_outputs[0] + + outputs = attention_outputs[1:] # add attentions if we output attention weights + + layer_output = apply_chunking_to_forward( + self.feed_forward_chunk, self.chunk_size_feed_forward, self.seq_len_dim, attention_output + ) + + layer_output = layer_output + attention_output # residual connection + + outputs = (layer_output,) + outputs + + return outputs + + def feed_forward_chunk(self, attention_output): + layer_output = self.layernorm(attention_output) + layer_output = self.mlp(layer_output) + return layer_output + + +class PerceiverEncoder(nn.Module): + """The Perceiver Encoder: a scalable, fully attentional encoder.""" + + def __init__(self, config, kv_dim=None): + super().__init__() + self.config = config + + # Check that we can use multihead-attention with these shapes. + if config.d_latents % config.num_self_attention_heads != 0: + raise ValueError( + f"num_z_channels ({config.d_latents}) must be divisible by" + f" num_self_attend_heads ({config.num_self_attention_heads})." + ) + if config.d_latents % config.num_cross_attention_heads != 0: + raise ValueError( + f"num_z_channels ({config.d_latents}) must be divisible by" + f" num_cross_attend_heads ({config.num_cross_attention_heads})." + ) + + # Construct the cross attention layer. + self.cross_attention = PerceiverLayer( + config, + is_cross_attention=True, + qk_channels=config.qk_channels, + v_channels=config.v_channels, + num_heads=config.num_cross_attention_heads, + q_dim=config.d_latents, + kv_dim=kv_dim, + widening_factor=config.cross_attention_widening_factor, + use_query_residual=config.use_query_residual, + ) + + # Construct a single block of self-attention layers. + # We get deeper architectures by applying this block more than once. + self_attention_layers = [] + for _ in range(config.num_self_attends_per_block): + layer = PerceiverLayer( + config, + is_cross_attention=False, + qk_channels=config.qk_channels, + v_channels=config.v_channels, + num_heads=config.num_self_attention_heads, + q_dim=config.d_latents, + kv_dim=config.d_latents, + widening_factor=config.self_attention_widening_factor, + ) + self_attention_layers.append(layer) + + self.self_attends = nn.ModuleList(self_attention_layers) + + def forward( + self, + hidden_states: torch.Tensor, + attention_mask: Optional[torch.FloatTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + inputs: Optional[torch.FloatTensor] = None, + inputs_mask: Optional[torch.FloatTensor] = None, + output_attentions: Optional[bool] = False, + output_hidden_states: Optional[bool] = False, + return_dict: Optional[bool] = True, + ) -> Union[Tuple, BaseModelOutputWithCrossAttentions]: + all_hidden_states = () if output_hidden_states else None + all_self_attentions = () if output_attentions else None + all_cross_attentions = () if output_attentions else None + + # Apply the cross-attention between the latents (hidden_states) and inputs: + layer_outputs = self.cross_attention( + hidden_states, + attention_mask=attention_mask, + head_mask=None, + inputs=inputs, + inputs_mask=inputs_mask, + output_attentions=output_attentions, + ) + hidden_states = layer_outputs[0] + + if output_attentions: + all_cross_attentions = all_cross_attentions + (layer_outputs[1],) + + # Apply the block of self-attention layers more than once: + for _ in range(self.config.num_blocks): + for i, layer_module in enumerate(self.self_attends): + if output_hidden_states: + all_hidden_states = all_hidden_states + (hidden_states,) + + layer_head_mask = head_mask[i] if head_mask is not None else None + + layer_outputs = layer_module( + hidden_states, + attention_mask=attention_mask, + head_mask=layer_head_mask, + output_attentions=output_attentions, + ) + + hidden_states = layer_outputs[0] + if output_attentions: + all_self_attentions = all_self_attentions + (layer_outputs[1],) + + if output_hidden_states: + all_hidden_states = all_hidden_states + (hidden_states,) + + if not return_dict: + return tuple( + v + for v in [hidden_states, all_hidden_states, all_self_attentions, all_cross_attentions] + if v is not None + ) + return BaseModelOutputWithCrossAttentions( + last_hidden_state=hidden_states, + hidden_states=all_hidden_states, + attentions=all_self_attentions, + cross_attentions=all_cross_attentions, + ) + + +class PerceiverPreTrainedModel(PreTrainedModel): + """ + An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained + models. + """ + + config_class = PerceiverConfig + base_model_prefix = "perceiver" + main_input_name = "inputs" + + def _init_weights(self, module): + """Initialize the weights""" + if isinstance(module, (nn.Linear, nn.Conv2d)): + # Slightly different from the TF version which uses truncated_normal for initialization + # cf https://github.com/pytorch/pytorch/pull/5617 + module.weight.data.normal_(mean=0.0, std=self.config.initializer_range) + if module.bias is not None: + module.bias.data.zero_() + elif hasattr(module, "latents"): + module.latents.data.normal_(mean=0.0, std=self.config.initializer_range) + elif hasattr(module, "position_embeddings") and isinstance(module, PerceiverTrainablePositionEncoding): + module.position_embeddings.data.normal_(mean=0.0, std=self.config.initializer_range) + elif isinstance(module, nn.ParameterDict): + for modality in module.keys(): + module[modality].data.normal_(mean=0.0, std=self.config.initializer_range) + elif isinstance(module, nn.Embedding): + module.weight.data.normal_(mean=0.0, std=self.config.initializer_range) + if module.padding_idx is not None: + module.weight.data[module.padding_idx].zero_() + elif isinstance(module, nn.LayerNorm): + module.bias.data.zero_() + module.weight.data.fill_(1.0) + + +PERCEIVER_START_DOCSTRING = r""" + This model is a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#torch.nn.Module) sub-class. Use + it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage and + behavior. + + Parameters: + config ([`PerceiverConfig`]): Model configuration class with all the parameters of the model. + Initializing with a config file does not load the weights associated with the model, only the + configuration. Check out the [`~PreTrainedModel.from_pretrained`] method to load the model weights. +""" + +PERCEIVER_MODEL_START_DOCSTRING = r""" + This model is a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#torch.nn.Module) sub-class. Use + it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage and + behavior. + + Parameters: + config ([`PerceiverConfig`]): Model configuration class with all the parameters of the model. + Initializing with a config file does not load the weights associated with the model, only the + configuration. Check out the [`~PreTrainedModel.from_pretrained`] method to load the model weights. + decoder (*DecoderType*, *optional*): + Optional decoder to use to decode the latent representation of the encoder. Examples include + *transformers.models.perceiver.modeling_perceiver.PerceiverBasicDecoder*, + *transformers.models.perceiver.modeling_perceiver.PerceiverClassificationDecoder*, + *transformers.models.perceiver.modeling_perceiver.PerceiverMultimodalDecoder*. + input_preprocessor (*PreprocessorType*, *optional*): + Optional input preprocessor to use. Examples include + *transformers.models.perceiver.modeling_perceiver.PerceiverImagePreprocessor*, + *transformers.models.perceiver.modeling_perceiver.PerceiverAudioPreprocessor*, + *transformers.models.perceiver.modeling_perceiver.PerceiverTextPreprocessor*, + *transformers.models.perceiver.modeling_perceiver.PerceiverMultimodalPreprocessor*. + output_postprocessor (*PostprocessorType*, *optional*): + Optional output postprocessor to use. Examples include + *transformers.models.perceiver.modeling_perceiver.PerceiverImagePostprocessor*, + *transformers.models.perceiver.modeling_perceiver.PerceiverAudioPostprocessor*, + *transformers.models.perceiver.modeling_perceiver.PerceiverClassificationPostprocessor*, + *transformers.models.perceiver.modeling_perceiver.PerceiverProjectionPostprocessor*, + *transformers.models.perceiver.modeling_perceiver.PerceiverMultimodalPostprocessor*. + + Note that you can define your own decoders, preprocessors and/or postprocessors to fit your use-case. +""" + +PERCEIVER_INPUTS_DOCSTRING = r""" + Args: + inputs (`torch.FloatTensor`): + Inputs to the perceiver. Can be anything: images, text, audio, video, etc. + attention_mask (`torch.FloatTensor` of shape `{0}`, *optional*): + Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`: + + - 1 for tokens that are **not masked**, + - 0 for tokens that are **masked**. + + [What are attention masks?](../glossary#attention-mask) + head_mask (`torch.FloatTensor` of shape `(num_heads,)` or `(num_layers, num_heads)`, *optional*): + Mask to nullify selected heads of the self-attention modules. Mask values selected in `[0, 1]`: + + - 1 indicates the head is **not masked**, + - 0 indicates the head is **masked**. + + output_attentions (`bool`, *optional*): + Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned + tensors for more detail. + output_hidden_states (`bool`, *optional*): + Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for + more detail. + return_dict (`bool`, *optional*): + Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple. +""" + + +@add_start_docstrings( + """The Perceiver: a scalable, fully attentional architecture.""", + PERCEIVER_MODEL_START_DOCSTRING, +) +class PerceiverModel(PerceiverPreTrainedModel): + def __init__( + self, + config, + decoder=None, + input_preprocessor: PreprocessorType = None, + output_postprocessor: PostprocessorType = None, + ): + super().__init__(config) + self.config = config + + self.input_preprocessor = input_preprocessor + self.output_postprocessor = output_postprocessor + self.embeddings = PerceiverEmbeddings(config) + self.encoder = PerceiverEncoder( + config, kv_dim=input_preprocessor.num_channels if input_preprocessor is not None else config.d_model + ) + self.decoder = decoder + + # Initialize weights and apply final processing + self.post_init() + + def get_input_embeddings(self): + return self.embeddings.latents + + def set_input_embeddings(self, value): + self.embeddings.latents = value + + def _prune_heads(self, heads_to_prune): + """ + Prunes heads of the model. heads_to_prune: dict of {layer_num: list of heads to prune in this layer} See base + class PreTrainedModel + """ + for layer, heads in heads_to_prune.items(): + self.encoder.layer[layer].attention.prune_heads(heads) + + @add_start_docstrings_to_model_forward(PERCEIVER_INPUTS_DOCSTRING.format("(batch_size, sequence_length)")) + @replace_return_docstrings(output_type=PerceiverModelOutput, config_class=_CONFIG_FOR_DOC) + def forward( + self, + inputs: torch.FloatTensor, + attention_mask: Optional[torch.FloatTensor] = None, + subsampled_output_points: Optional[Dict[str, torch.Tensor]] = None, + head_mask: Optional[torch.FloatTensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple, PerceiverModelOutput]: + r""" + Returns: + + Examples: + + ```python + >>> from transformers import PerceiverConfig, PerceiverTokenizer, PerceiverImageProcessor, PerceiverModel + >>> from transformers.models.perceiver.modeling_perceiver import ( + ... PerceiverTextPreprocessor, + ... PerceiverImagePreprocessor, + ... PerceiverClassificationDecoder, + ... ) + >>> import torch + >>> import requests + >>> from PIL import Image + + >>> # EXAMPLE 1: using the Perceiver to classify texts + >>> # - we define a TextPreprocessor, which can be used to embed tokens + >>> # - we define a ClassificationDecoder, which can be used to decode the + >>> # final hidden states of the latents to classification logits + >>> # using trainable position embeddings + >>> config = PerceiverConfig() + >>> preprocessor = PerceiverTextPreprocessor(config) + >>> decoder = PerceiverClassificationDecoder( + ... config, + ... num_channels=config.d_latents, + ... trainable_position_encoding_kwargs=dict(num_channels=config.d_latents, index_dims=1), + ... use_query_residual=True, + ... ) + >>> model = PerceiverModel(config, input_preprocessor=preprocessor, decoder=decoder) + + >>> # you can then do a forward pass as follows: + >>> tokenizer = PerceiverTokenizer() + >>> text = "hello world" + >>> inputs = tokenizer(text, return_tensors="pt").input_ids + + >>> with torch.no_grad(): + ... outputs = model(inputs=inputs) + >>> logits = outputs.logits + >>> list(logits.shape) + [1, 2] + + >>> # to train, one can train the model using standard cross-entropy: + >>> criterion = torch.nn.CrossEntropyLoss() + + >>> labels = torch.tensor([1]) + >>> loss = criterion(logits, labels) + + >>> # EXAMPLE 2: using the Perceiver to classify images + >>> # - we define an ImagePreprocessor, which can be used to embed images + >>> config = PerceiverConfig(image_size=224) + >>> preprocessor = PerceiverImagePreprocessor( + ... config, + ... prep_type="conv1x1", + ... spatial_downsample=1, + ... out_channels=256, + ... position_encoding_type="trainable", + ... concat_or_add_pos="concat", + ... project_pos_dim=256, + ... trainable_position_encoding_kwargs=dict( + ... num_channels=256, + ... index_dims=config.image_size**2, + ... ), + ... ) + + >>> model = PerceiverModel( + ... config, + ... input_preprocessor=preprocessor, + ... decoder=PerceiverClassificationDecoder( + ... config, + ... num_channels=config.d_latents, + ... trainable_position_encoding_kwargs=dict(num_channels=config.d_latents, index_dims=1), + ... use_query_residual=True, + ... ), + ... ) + + >>> # you can then do a forward pass as follows: + >>> image_processor = PerceiverImageProcessor() + >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg" + >>> image = Image.open(requests.get(url, stream=True).raw) + >>> inputs = image_processor(image, return_tensors="pt").pixel_values + + >>> with torch.no_grad(): + ... outputs = model(inputs=inputs) + >>> logits = outputs.logits + >>> list(logits.shape) + [1, 2] + + >>> # to train, one can train the model using standard cross-entropy: + >>> criterion = torch.nn.CrossEntropyLoss() + + >>> labels = torch.tensor([1]) + >>> loss = criterion(logits, labels) + ```""" + output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions + output_hidden_states = ( + output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states + ) + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + if self.input_preprocessor is not None: + inputs, modality_sizes, inputs_without_pos = self.input_preprocessor(inputs) + else: + modality_sizes = None + inputs_without_pos = None + if inputs.size()[-1] != self.config.d_model: + raise ValueError( + f"Last dimension of the inputs: {inputs.size()[-1]} doesn't correspond to config.d_model:" + f" {self.config.d_model}. Make sure to set config.d_model appropriately." + ) + + batch_size, seq_length, _ = inputs.size() + device = inputs.device + + # If no attention mask is provided, make them all ones + if attention_mask is None: + attention_mask = torch.ones((batch_size, seq_length), device=device) + # Make the attention mask broadcastable to [batch_size, num_heads, seq_length, seq_length] + extended_attention_mask = self.invert_attention_mask(attention_mask) + + # Prepare head mask if needed + # 1.0 in head_mask indicate we keep the head + # attention_probs has shape bsz x n_heads x N x N + # input head_mask has shape [num_heads] or [num_blocks x num_heads] + # and head_mask is converted to shape [num_blocks x batch x num_heads x N x N] + head_mask = self.get_head_mask(head_mask, self.config.num_blocks * self.config.num_self_attends_per_block) + + embedding_output = self.embeddings(batch_size=batch_size) + + encoder_outputs = self.encoder( + embedding_output, + attention_mask=None, + head_mask=head_mask, + inputs=inputs, + inputs_mask=extended_attention_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + sequence_output = encoder_outputs[0] + + logits = None + if self.decoder: + if subsampled_output_points is not None: + output_modality_sizes = { + "audio": subsampled_output_points["audio"].shape[0], + "image": subsampled_output_points["image"].shape[0], + "label": 1, + } + else: + output_modality_sizes = modality_sizes + decoder_query = self.decoder.decoder_query( + inputs, modality_sizes, inputs_without_pos, subsampled_points=subsampled_output_points + ) + decoder_outputs = self.decoder( + decoder_query, + z=sequence_output, + query_mask=extended_attention_mask, + output_attentions=output_attentions, + ) + logits = decoder_outputs.logits + + # add cross-attentions of decoder + if output_attentions and decoder_outputs.cross_attentions is not None: + if return_dict: + encoder_outputs.cross_attentions = ( + encoder_outputs.cross_attentions + decoder_outputs.cross_attentions + ) + else: + encoder_outputs = encoder_outputs + decoder_outputs.cross_attentions + + if self.output_postprocessor: + logits = self.output_postprocessor(logits, modality_sizes=output_modality_sizes) + + if not return_dict: + if logits is not None: + return (logits, sequence_output) + encoder_outputs[1:] + else: + return (sequence_output,) + encoder_outputs[1:] + + return PerceiverModelOutput( + logits=logits, + last_hidden_state=sequence_output, + hidden_states=encoder_outputs.hidden_states, + attentions=encoder_outputs.attentions, + cross_attentions=encoder_outputs.cross_attentions, + ) + + +@add_start_docstrings("""Example use of Perceiver for masked language modeling.""", PERCEIVER_START_DOCSTRING) +class PerceiverForMaskedLM(PerceiverPreTrainedModel): + def __init__(self, config: PerceiverConfig): + super().__init__(config) + + text_preprocessor = PerceiverTextPreprocessor(config) + + trainable_position_encoding_kwargs_decoder = { + "num_channels": text_preprocessor.num_channels, + "index_dims": config.max_position_embeddings, + } + + self.perceiver = PerceiverModel( + config, + input_preprocessor=text_preprocessor, + decoder=PerceiverBasicDecoder( + config, + output_num_channels=config.d_latents, + output_index_dims=config.max_position_embeddings, # we need to define the seq_len of the inputs beforehand + num_channels=text_preprocessor.num_channels, + qk_channels=8 * 32, + v_channels=text_preprocessor.num_channels, + num_heads=8, + use_query_residual=False, + final_project=False, + trainable_position_encoding_kwargs=trainable_position_encoding_kwargs_decoder, + ), + ) + self.embedding_decoder = PerceiverEmbeddingDecoder(config) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward(PERCEIVER_INPUTS_DOCSTRING.format("batch_size, sequence_length")) + @replace_return_docstrings(output_type=PerceiverMaskedLMOutput, config_class=_CONFIG_FOR_DOC) + def forward( + self, + inputs: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + labels: Optional[torch.Tensor] = None, + return_dict: Optional[bool] = None, + input_ids: Optional[torch.Tensor] = None, + ) -> Union[Tuple, PerceiverMaskedLMOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*): + Labels for computing the masked language modeling loss. Indices should be in `[-100, 0, ..., + config.vocab_size]` (see `input_ids` docstring) Tokens with indices set to `-100` are ignored (masked), the + loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]` + + Returns: + + Examples: + + ```python + >>> from transformers import AutoTokenizer, PerceiverForMaskedLM + >>> import torch + + >>> tokenizer = AutoTokenizer.from_pretrained("deepmind/language-perceiver") + >>> model = PerceiverForMaskedLM.from_pretrained("deepmind/language-perceiver") + + >>> # training + >>> text = "This is an incomplete sentence where some words are missing." + >>> inputs = tokenizer(text, padding="max_length", return_tensors="pt") + >>> # mask " missing." + >>> inputs["input_ids"][0, 52:61] = tokenizer.mask_token_id + >>> labels = tokenizer(text, padding="max_length", return_tensors="pt").input_ids + + >>> outputs = model(**inputs, labels=labels) + >>> loss = outputs.loss + >>> round(loss.item(), 2) + 19.87 + + >>> logits = outputs.logits + >>> list(logits.shape) + [1, 2048, 262] + + >>> # inference + >>> text = "This is an incomplete sentence where some words are missing." + >>> encoding = tokenizer(text, padding="max_length", return_tensors="pt") + + >>> # mask bytes corresponding to " missing.". Note that the model performs much better if the masked span starts with a space. + >>> encoding["input_ids"][0, 52:61] = tokenizer.mask_token_id + + >>> # forward pass + >>> with torch.no_grad(): + ... outputs = model(**encoding) + >>> logits = outputs.logits + >>> list(logits.shape) + [1, 2048, 262] + + >>> masked_tokens_predictions = logits[0, 52:61].argmax(dim=-1).tolist() + >>> tokenizer.decode(masked_tokens_predictions) + ' missing.' + ```""" + if inputs is not None and input_ids is not None: + raise ValueError("You cannot use both `inputs` and `input_ids`") + elif inputs is None and input_ids is not None: + inputs = input_ids + + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + outputs = self.perceiver( + inputs=inputs, + attention_mask=attention_mask, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + + logits = self.embedding_decoder( + outputs.logits if return_dict else outputs[0], embedding_layer=self.perceiver.input_preprocessor.embeddings + ) + + masked_lm_loss = None + if labels is not None: + loss_fct = CrossEntropyLoss() # -100 index = padding token + masked_lm_loss = loss_fct(logits.view(-1, self.config.vocab_size), labels.view(-1)) + + if not return_dict: + output = (logits,) + outputs[2:] + return ((masked_lm_loss,) + output) if masked_lm_loss is not None else output + + return PerceiverMaskedLMOutput( + loss=masked_lm_loss, + logits=logits, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + cross_attentions=outputs.cross_attentions, + ) + + +@add_start_docstrings("""Example use of Perceiver for text classification.""", PERCEIVER_START_DOCSTRING) +class PerceiverForSequenceClassification(PerceiverPreTrainedModel): + def __init__(self, config): + super().__init__(config) + + trainable_position_encoding_kwargs_decoder = {"num_channels": config.d_latents, "index_dims": 1} + + self.num_labels = config.num_labels + self.perceiver = PerceiverModel( + config, + input_preprocessor=PerceiverTextPreprocessor(config), + decoder=PerceiverClassificationDecoder( + config, + num_channels=config.d_latents, + trainable_position_encoding_kwargs=trainable_position_encoding_kwargs_decoder, + use_query_residual=True, + ), + ) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward(PERCEIVER_INPUTS_DOCSTRING.format("batch_size, sequence_length")) + @replace_return_docstrings(output_type=PerceiverClassifierOutput, config_class=_CONFIG_FOR_DOC) + def forward( + self, + inputs: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + labels: Optional[torch.Tensor] = None, + return_dict: Optional[bool] = None, + input_ids: Optional[torch.Tensor] = None, + ) -> Union[Tuple, PerceiverClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the classification/regression loss. Indices should be in `[0, ..., config.num_labels - + 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If `config.num_labels > + 1` a classification loss is computed (Cross-Entropy). + + Returns: + + Examples: + + ```python + >>> from transformers import AutoTokenizer, PerceiverForSequenceClassification + + >>> tokenizer = AutoTokenizer.from_pretrained("deepmind/language-perceiver") + >>> model = PerceiverForSequenceClassification.from_pretrained("deepmind/language-perceiver") + + >>> text = "hello world" + >>> inputs = tokenizer(text, return_tensors="pt").input_ids + >>> outputs = model(inputs=inputs) + >>> logits = outputs.logits + >>> list(logits.shape) + [1, 2] + ```""" + if inputs is not None and input_ids is not None: + raise ValueError("You cannot use both `inputs` and `input_ids`") + elif inputs is None and input_ids is not None: + inputs = input_ids + + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + outputs = self.perceiver( + inputs=inputs, + attention_mask=attention_mask, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + + logits = outputs.logits if return_dict else outputs[0] + + loss = None + if labels is not None: + if self.config.problem_type is None: + if self.num_labels == 1: + self.config.problem_type = "regression" + elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int): + self.config.problem_type = "single_label_classification" + else: + self.config.problem_type = "multi_label_classification" + + if self.config.problem_type == "regression": + loss_fct = MSELoss() + if self.num_labels == 1: + loss = loss_fct(logits.squeeze(), labels.squeeze()) + else: + loss = loss_fct(logits, labels) + elif self.config.problem_type == "single_label_classification": + loss_fct = CrossEntropyLoss() + loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1)) + elif self.config.problem_type == "multi_label_classification": + loss_fct = BCEWithLogitsLoss() + loss = loss_fct(logits, labels) + + if not return_dict: + output = (logits,) + outputs[2:] + return ((loss,) + output) if loss is not None else output + + return PerceiverClassifierOutput( + loss=loss, + logits=logits, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + cross_attentions=outputs.cross_attentions, + ) + + +@add_start_docstrings( + """ +Example use of Perceiver for image classification, for tasks such as ImageNet. + +This model uses learned position embeddings. In other words, this model is not given any privileged information about +the structure of images. As shown in the paper, this model can achieve a top-1 accuracy of 72.7 on ImageNet. + +[`PerceiverForImageClassificationLearned`] uses [`~models.perceiver.modeling_perceiver.PerceiverImagePreprocessor`] +(with `prep_type="conv1x1"`) to preprocess the input images, and +[`~models.perceiver.modeling_perceiver.PerceiverClassificationDecoder`] to decode the latent representation of +[`PerceiverModel`] into classification logits. +""", + PERCEIVER_START_DOCSTRING, +) +class PerceiverForImageClassificationLearned(PerceiverPreTrainedModel): + def __init__(self, config): + super().__init__(config) + + trainable_position_encoding_kwargs_preprocessor = {"num_channels": 256, "index_dims": config.image_size**2} + trainable_position_encoding_kwargs_decoder = {"num_channels": config.d_latents, "index_dims": 1} + + self.num_labels = config.num_labels + self.perceiver = PerceiverModel( + config, + input_preprocessor=PerceiverImagePreprocessor( + config, + prep_type="conv1x1", + spatial_downsample=1, + out_channels=256, + position_encoding_type="trainable", + concat_or_add_pos="concat", + project_pos_dim=256, + trainable_position_encoding_kwargs=trainable_position_encoding_kwargs_preprocessor, + ), + decoder=PerceiverClassificationDecoder( + config, + num_channels=config.d_latents, + trainable_position_encoding_kwargs=trainable_position_encoding_kwargs_decoder, + use_query_residual=True, + ), + ) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward(PERCEIVER_INPUTS_DOCSTRING.format("batch_size, sequence_length")) + @replace_return_docstrings(output_type=PerceiverClassifierOutput, config_class=_CONFIG_FOR_DOC) + def forward( + self, + inputs: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + labels: Optional[torch.Tensor] = None, + return_dict: Optional[bool] = None, + pixel_values: Optional[torch.Tensor] = None, + ) -> Union[Tuple, PerceiverClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the image classification/regression loss. Indices should be in `[0, ..., + config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If + `config.num_labels > 1` a classification loss is computed (Cross-Entropy). + + Returns: + + Examples: + + ```python + >>> from transformers import AutoImageProcessor, PerceiverForImageClassificationLearned + >>> from PIL import Image + >>> import requests + + >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg" + >>> image = Image.open(requests.get(url, stream=True).raw) + + >>> image_processor = AutoImageProcessor.from_pretrained("deepmind/vision-perceiver-learned") + >>> model = PerceiverForImageClassificationLearned.from_pretrained("deepmind/vision-perceiver-learned") + + >>> inputs = image_processor(images=image, return_tensors="pt").pixel_values + >>> outputs = model(inputs=inputs) + >>> logits = outputs.logits + >>> list(logits.shape) + [1, 1000] + + >>> # model predicts one of the 1000 ImageNet classes + >>> predicted_class_idx = logits.argmax(-1).item() + >>> print("Predicted class:", model.config.id2label[predicted_class_idx]) + Predicted class: tabby, tabby cat + ```""" + if inputs is not None and pixel_values is not None: + raise ValueError("You cannot use both `inputs` and `pixel_values`") + elif inputs is None and pixel_values is not None: + inputs = pixel_values + + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + outputs = self.perceiver( + inputs=inputs, + attention_mask=attention_mask, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + logits = outputs.logits if return_dict else outputs[0] + + loss = None + if labels is not None: + if self.config.problem_type is None: + if self.num_labels == 1: + self.config.problem_type = "regression" + elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int): + self.config.problem_type = "single_label_classification" + else: + self.config.problem_type = "multi_label_classification" + + if self.config.problem_type == "regression": + loss_fct = MSELoss() + if self.num_labels == 1: + loss = loss_fct(logits.squeeze(), labels.squeeze()) + else: + loss = loss_fct(logits, labels) + elif self.config.problem_type == "single_label_classification": + loss_fct = CrossEntropyLoss() + loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1)) + elif self.config.problem_type == "multi_label_classification": + loss_fct = BCEWithLogitsLoss() + loss = loss_fct(logits, labels) + + if not return_dict: + output = (logits,) + outputs[2:] + return ((loss,) + output) if loss is not None else output + + return PerceiverClassifierOutput( + loss=loss, + logits=logits, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + cross_attentions=outputs.cross_attentions, + ) + + +@add_start_docstrings( + """ +Example use of Perceiver for image classification, for tasks such as ImageNet. + +This model uses fixed 2D Fourier position embeddings. As shown in the paper, this model can achieve a top-1 accuracy of +79.0 on ImageNet, and 84.5 when pre-trained on a large-scale dataset (i.e. JFT). + +[`PerceiverForImageClassificationLearned`] uses [`~models.perceiver.modeling_perceiver.PerceiverImagePreprocessor`] +(with `prep_type="pixels"`) to preprocess the input images, and +[`~models.perceiver.modeling_perceiver.PerceiverClassificationDecoder`] to decode the latent representation of +[`PerceiverModel`] into classification logits. +""", + PERCEIVER_START_DOCSTRING, +) +class PerceiverForImageClassificationFourier(PerceiverPreTrainedModel): + def __init__(self, config): + super().__init__(config) + + fourier_position_encoding_kwargs_preprocessor = { + "concat_pos": True, + "max_resolution": (224, 224), + "num_bands": 64, + "sine_only": False, + } + trainable_position_encoding_kwargs_decoder = {"num_channels": config.d_latents, "index_dims": 1} + + self.num_labels = config.num_labels + self.perceiver = PerceiverModel( + config, + input_preprocessor=PerceiverImagePreprocessor( + config, + prep_type="pixels", + spatial_downsample=1, + fourier_position_encoding_kwargs=fourier_position_encoding_kwargs_preprocessor, + ), + decoder=PerceiverClassificationDecoder( + config, + num_channels=config.d_latents, + trainable_position_encoding_kwargs=trainable_position_encoding_kwargs_decoder, + use_query_residual=True, + ), + ) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward(PERCEIVER_INPUTS_DOCSTRING.format("batch_size, sequence_length")) + @replace_return_docstrings(output_type=PerceiverClassifierOutput, config_class=_CONFIG_FOR_DOC) + def forward( + self, + inputs: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + labels: Optional[torch.Tensor] = None, + return_dict: Optional[bool] = None, + pixel_values: Optional[torch.Tensor] = None, + ) -> Union[Tuple, PerceiverClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the image classification/regression loss. Indices should be in `[0, ..., + config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If + `config.num_labels > 1` a classification loss is computed (Cross-Entropy). + + Returns: + + Examples: + + ```python + >>> from transformers import AutoImageProcessor, PerceiverForImageClassificationFourier + >>> from PIL import Image + >>> import requests + + >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg" + >>> image = Image.open(requests.get(url, stream=True).raw) + + >>> image_processor = AutoImageProcessor.from_pretrained("deepmind/vision-perceiver-fourier") + >>> model = PerceiverForImageClassificationFourier.from_pretrained("deepmind/vision-perceiver-fourier") + + >>> inputs = image_processor(images=image, return_tensors="pt").pixel_values + >>> outputs = model(inputs=inputs) + >>> logits = outputs.logits + >>> list(logits.shape) + [1, 1000] + + >>> # model predicts one of the 1000 ImageNet classes + >>> predicted_class_idx = logits.argmax(-1).item() + >>> print("Predicted class:", model.config.id2label[predicted_class_idx]) + Predicted class: tabby, tabby cat + ```""" + if inputs is not None and pixel_values is not None: + raise ValueError("You cannot use both `inputs` and `pixel_values`") + elif inputs is None and pixel_values is not None: + inputs = pixel_values + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + outputs = self.perceiver( + inputs=inputs, + attention_mask=attention_mask, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + logits = outputs.logits if return_dict else outputs[0] + + loss = None + if labels is not None: + if self.config.problem_type is None: + if self.num_labels == 1: + self.config.problem_type = "regression" + elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int): + self.config.problem_type = "single_label_classification" + else: + self.config.problem_type = "multi_label_classification" + + if self.config.problem_type == "regression": + loss_fct = MSELoss() + if self.num_labels == 1: + loss = loss_fct(logits.squeeze(), labels.squeeze()) + else: + loss = loss_fct(logits, labels) + elif self.config.problem_type == "single_label_classification": + loss_fct = CrossEntropyLoss() + loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1)) + elif self.config.problem_type == "multi_label_classification": + loss_fct = BCEWithLogitsLoss() + loss = loss_fct(logits, labels) + + if not return_dict: + output = (logits,) + outputs[2:] + return ((loss,) + output) if loss is not None else output + + return PerceiverClassifierOutput( + loss=loss, + logits=logits, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + cross_attentions=outputs.cross_attentions, + ) + + +@add_start_docstrings( + """ +Example use of Perceiver for image classification, for tasks such as ImageNet. + +This model uses a 2D conv+maxpool preprocessing network. As shown in the paper, this model can achieve a top-1 accuracy +of 82.1 on ImageNet. + +[`PerceiverForImageClassificationLearned`] uses [`~models.perceiver.modeling_perceiver.PerceiverImagePreprocessor`] +(with `prep_type="conv"`) to preprocess the input images, and +[`~models.perceiver.modeling_perceiver.PerceiverClassificationDecoder`] to decode the latent representation of +[`PerceiverModel`] into classification logits. +""", + PERCEIVER_START_DOCSTRING, +) +class PerceiverForImageClassificationConvProcessing(PerceiverPreTrainedModel): + def __init__(self, config): + super().__init__(config) + + fourier_position_encoding_kwargs_preprocessor = { + "concat_pos": True, + "max_resolution": (56, 56), + "num_bands": 64, + "sine_only": False, + } + trainable_position_encoding_kwargs_decoder = {"num_channels": config.d_latents, "index_dims": 1} + + self.num_labels = config.num_labels + self.perceiver = PerceiverModel( + config, + input_preprocessor=PerceiverImagePreprocessor( + config, + prep_type="conv", + spatial_downsample=1, + position_encoding_type="fourier", + fourier_position_encoding_kwargs=fourier_position_encoding_kwargs_preprocessor, + ), + decoder=PerceiverClassificationDecoder( + config, + num_channels=config.d_latents, + trainable_position_encoding_kwargs=trainable_position_encoding_kwargs_decoder, + use_query_residual=True, + ), + ) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward(PERCEIVER_INPUTS_DOCSTRING.format("batch_size, sequence_length")) + @replace_return_docstrings(output_type=PerceiverClassifierOutput, config_class=_CONFIG_FOR_DOC) + def forward( + self, + inputs: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + labels: Optional[torch.Tensor] = None, + return_dict: Optional[bool] = None, + pixel_values: Optional[torch.Tensor] = None, + ) -> Union[Tuple, PerceiverClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the image classification/regression loss. Indices should be in `[0, ..., + config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If + `config.num_labels > 1` a classification loss is computed (Cross-Entropy). + + Returns: + + Examples: + + ```python + >>> from transformers import AutoImageProcessor, PerceiverForImageClassificationConvProcessing + >>> from PIL import Image + >>> import requests + + >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg" + >>> image = Image.open(requests.get(url, stream=True).raw) + + >>> image_processor = AutoImageProcessor.from_pretrained("deepmind/vision-perceiver-conv") + >>> model = PerceiverForImageClassificationConvProcessing.from_pretrained("deepmind/vision-perceiver-conv") + + >>> inputs = image_processor(images=image, return_tensors="pt").pixel_values + >>> outputs = model(inputs=inputs) + >>> logits = outputs.logits + >>> list(logits.shape) + [1, 1000] + + >>> # model predicts one of the 1000 ImageNet classes + >>> predicted_class_idx = logits.argmax(-1).item() + >>> print("Predicted class:", model.config.id2label[predicted_class_idx]) + Predicted class: tabby, tabby cat + ```""" + if inputs is not None and pixel_values is not None: + raise ValueError("You cannot use both `inputs` and `pixel_values`") + elif inputs is None and pixel_values is not None: + inputs = pixel_values + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + outputs = self.perceiver( + inputs=inputs, + attention_mask=attention_mask, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + logits = outputs.logits if return_dict else outputs[0] + + loss = None + if labels is not None: + if self.config.problem_type is None: + if self.num_labels == 1: + self.config.problem_type = "regression" + elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int): + self.config.problem_type = "single_label_classification" + else: + self.config.problem_type = "multi_label_classification" + + if self.config.problem_type == "regression": + loss_fct = MSELoss() + if self.num_labels == 1: + loss = loss_fct(logits.squeeze(), labels.squeeze()) + else: + loss = loss_fct(logits, labels) + elif self.config.problem_type == "single_label_classification": + loss_fct = CrossEntropyLoss() + loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1)) + elif self.config.problem_type == "multi_label_classification": + loss_fct = BCEWithLogitsLoss() + loss = loss_fct(logits, labels) + + if not return_dict: + output = (logits,) + outputs[2:] + return ((loss,) + output) if loss is not None else output + + return PerceiverClassifierOutput( + loss=loss, + logits=logits, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + cross_attentions=outputs.cross_attentions, + ) + + +@add_start_docstrings( + """ +Example use of Perceiver for optical flow, for tasks such as Sintel and KITTI. [`PerceiverForOpticalFlow`] uses +[`~models.perceiver.modeling_perceiver.PerceiverImagePreprocessor`] (with *prep_type="patches"*) to preprocess the +input images, and [`~models.perceiver.modeling_perceiver.PerceiverOpticalFlowDecoder`] to decode the latent +representation of [`PerceiverModel`]. + +As input, one concatenates 2 subsequent frames along the channel dimension and extract a 3 x 3 patch around each pixel +(leading to 3 x 3 x 3 x 2 = 54 values for each pixel). Fixed Fourier position encodings are used to encode the position +of each pixel in the patch. Next, one applies the Perceiver encoder. To decode, one queries the latent representation +using the same encoding used for the input. +""", + PERCEIVER_START_DOCSTRING, +) +class PerceiverForOpticalFlow(PerceiverPreTrainedModel): + def __init__(self, config): + super().__init__(config) + + fourier_position_encoding_kwargs_preprocessor = { + "num_bands": 64, + "max_resolution": config.train_size, + "sine_only": False, + "concat_pos": True, + } + fourier_position_encoding_kwargs_decoder = { + "concat_pos": True, + "max_resolution": config.train_size, + "num_bands": 64, + "sine_only": False, + } + + image_preprocessor = PerceiverImagePreprocessor( + config, + prep_type="patches", + spatial_downsample=1, + conv_after_patching=True, + conv_after_patching_in_channels=54, + temporal_downsample=2, + position_encoding_type="fourier", + # position_encoding_kwargs + fourier_position_encoding_kwargs=fourier_position_encoding_kwargs_preprocessor, + ) + + self.perceiver = PerceiverModel( + config, + input_preprocessor=image_preprocessor, + decoder=PerceiverOpticalFlowDecoder( + config, + num_channels=image_preprocessor.num_channels, + output_image_shape=config.train_size, + rescale_factor=100.0, + # decoder kwargs + use_query_residual=False, + output_num_channels=2, + # We query the decoder using the first frame features + # rather than a standard decoder position encoding. + position_encoding_type="fourier", + fourier_position_encoding_kwargs=fourier_position_encoding_kwargs_decoder, + ), + ) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward(PERCEIVER_INPUTS_DOCSTRING.format("batch_size, sequence_length")) + @replace_return_docstrings(output_type=PerceiverClassifierOutput, config_class=_CONFIG_FOR_DOC) + def forward( + self, + inputs: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + labels: Optional[torch.Tensor] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple, PerceiverClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the optical flow loss. Indices should be in `[0, ..., config.num_labels - 1]`. + + Returns: + + Examples: + + ```python + >>> from transformers import PerceiverForOpticalFlow + >>> import torch + + >>> model = PerceiverForOpticalFlow.from_pretrained("deepmind/optical-flow-perceiver") + + >>> # in the Perceiver IO paper, the authors extract a 3 x 3 patch around each pixel, + >>> # leading to 3 x 3 x 3 = 27 values for each pixel (as each pixel also has 3 color channels) + >>> # patches have shape (batch_size, num_frames, num_channels, height, width) + >>> # the authors train on resolutions of 368 x 496 + >>> patches = torch.randn(1, 2, 27, 368, 496) + >>> outputs = model(inputs=patches) + >>> logits = outputs.logits + >>> list(logits.shape) + [1, 368, 496, 2] + ```""" + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + outputs = self.perceiver( + inputs=inputs, + attention_mask=attention_mask, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + logits = outputs.logits if return_dict else outputs[0] + + loss = None + if labels is not None: + raise NotImplementedError("Optical flow training is not yet supported") + + if not return_dict: + output = (logits,) + outputs[2:] + return ((loss,) + output) if loss is not None else output + + return PerceiverClassifierOutput( + loss=loss, + logits=logits, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + cross_attentions=outputs.cross_attentions, + ) + + +@add_start_docstrings( + """ +Example use of Perceiver for multimodal (video) autoencoding, for tasks such as Kinetics-700. + +[`PerceiverForMultimodalAutoencoding`] uses [`~models.perceiver.modeling_perceiver.PerceiverMultimodalPreprocessor`] to +preprocess the 3 modalities: images, audio and class labels. This preprocessor uses modality-specific preprocessors to +preprocess every modality separately, after which they are concatenated. Trainable position embeddings are used to pad +each modality to the same number of channels to make concatenation along the time dimension possible. Next, one applies +the Perceiver encoder. + +[`~models.perceiver.modeling_perceiver.PerceiverMultimodalDecoder`] is used to decode the latent representation of +[`PerceiverModel`]. This decoder uses each modality-specific decoder to construct queries. The decoder queries are +created based on the inputs after preprocessing. However, autoencoding an entire video in a single forward pass is +computationally infeasible, hence one only uses parts of the decoder queries to do cross-attention with the latent +representation. This is determined by the subsampled indices for each modality, which can be provided as additional +input to the forward pass of [`PerceiverForMultimodalAutoencoding`]. + +[`~models.perceiver.modeling_perceiver.PerceiverMultimodalDecoder`] also pads the decoder queries of the different +modalities to the same number of channels, in order to concatenate them along the time dimension. Next, cross-attention +is performed with the latent representation of [`PerceiverModel`]. + +Finally, [`~models.perceiver.modeling_perceiver.PerceiverMultiModalPostprocessor`] is used to turn this tensor into an +actual video. It first splits up the output into the different modalities, and then applies the respective +postprocessor for each modality. + +Note that, by masking the classification label during evaluation (i.e. simply providing a tensor of zeros for the +"label" modality), this auto-encoding model becomes a Kinetics 700 video classifier. +""", + PERCEIVER_START_DOCSTRING, +) +class PerceiverForMultimodalAutoencoding(PerceiverPreTrainedModel): + def __init__(self, config: PerceiverConfig): + super().__init__(config) + + n_audio_samples = config.num_frames * config.audio_samples_per_frame + + input_preprocessor = PerceiverMultimodalPreprocessor( + min_padding_size=4, + modalities={ + "audio": PerceiverAudioPreprocessor( + config, + position_encoding_type="fourier", + fourier_position_encoding_kwargs={ + "num_bands": 192, + "max_resolution": (n_audio_samples,), + "sine_only": False, + "concat_pos": True, + }, + prep_type="patches", + samples_per_patch=config.samples_per_patch, + ), + "image": PerceiverImagePreprocessor( + config, + position_encoding_type="fourier", + fourier_position_encoding_kwargs={ + "num_bands": 32, + "max_resolution": (config.num_frames, config.image_size, config.image_size), + "sine_only": False, + "concat_pos": True, + }, + prep_type="patches", + spatial_downsample=4, + temporal_downsample=1, + ), + "label": PerceiverOneHotPreprocessor(config), + }, + mask_probs={"image": 0.0, "audio": 0.0, "label": 1.0}, + ) + + image_decoder = PerceiverBasicVideoAutoencodingDecoder( + config, + # Autoencoding, don't pass inputs to the queries. + concat_preprocessed_input=False, + output_shape=config.output_shape, + output_num_channels=config.output_num_channels, + use_query_residual=False, + position_encoding_only=True, + position_encoding_type="fourier", + fourier_position_encoding_kwargs={ + "num_bands": 32, + "max_resolution": (config.num_frames, config.image_size, config.image_size), + "sine_only": False, + "concat_pos": True, + }, + ) + + decoder = PerceiverMultimodalDecoder( + config, + # Autoencoding, don't pass inputs to the queries. + concat_preprocessed_input=False, + # Modality specific decoders are used ONLY to generate queries. + # All modalties are decoded together using a unified decoder. + modalities={ + "audio": PerceiverBasicDecoder( + config, + # Autoencoding, don't pass inputs to the queries. + concat_preprocessed_input=False, + output_index_dims=(n_audio_samples // config.samples_per_patch,), + output_num_channels=config.output_num_channels, + use_query_residual=False, + position_encoding_only=True, + position_encoding_type="fourier", + fourier_position_encoding_kwargs={ + "num_bands": 192, + "max_resolution": (n_audio_samples,), + "sine_only": False, + "concat_pos": True, + }, + ), + "image": image_decoder, + "label": PerceiverClassificationDecoder( + config, + # Autoencoding, don't pass inputs to the queries. + concat_preprocessed_input=False, + use_query_residual=False, + position_encoding_only=True, + position_encoding_type="trainable", + trainable_position_encoding_kwargs={ + "num_channels": config._label_trainable_num_channels, + "index_dims": 1, + }, + ), + }, + num_outputs=None, + output_num_channels=config.output_num_channels, + use_query_residual=False, + ) + + output_postprocessor = PerceiverMultimodalPostprocessor( + modalities={ + "audio": PerceiverAudioPostprocessor(config, in_channels=config.output_num_channels), + "image": PerceiverProjectionPostprocessor(in_channels=config.output_num_channels, out_channels=3), + "label": PerceiverClassificationPostprocessor(config, in_channels=config.output_num_channels), + } + ) + + self.perceiver = PerceiverModel( + config, + input_preprocessor=input_preprocessor, + decoder=decoder, + output_postprocessor=output_postprocessor, + ) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward(PERCEIVER_INPUTS_DOCSTRING.format("batch_size, sequence_length")) + @replace_return_docstrings(output_type=PerceiverClassifierOutput, config_class=_CONFIG_FOR_DOC) + def forward( + self, + inputs: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + subsampled_output_points: Optional[Dict[str, torch.Tensor]] = None, + head_mask: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + labels: Optional[torch.Tensor] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple, PerceiverClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the image classification/regression loss. Indices should be in `[0, ..., + config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If + `config.num_labels > 1` a classification loss is computed (Cross-Entropy). + + Returns: + + Examples: + + ```python + >>> from transformers import PerceiverForMultimodalAutoencoding + >>> import torch + >>> import numpy as np + + >>> # create multimodal inputs + >>> images = torch.randn((1, 16, 3, 224, 224)) + >>> audio = torch.randn((1, 30720, 1)) + >>> inputs = dict(image=images, audio=audio, label=torch.zeros((images.shape[0], 700))) + + >>> model = PerceiverForMultimodalAutoencoding.from_pretrained("deepmind/multimodal-perceiver") + + >>> # in the Perceiver IO paper, videos are auto-encoded in chunks + >>> # each chunk subsamples different index dimensions of the image and audio modality decoder queries + >>> nchunks = 128 + >>> image_chunk_size = np.prod((16, 224, 224)) // nchunks + >>> audio_chunk_size = audio.shape[1] // model.config.samples_per_patch // nchunks + >>> # process the first chunk + >>> chunk_idx = 0 + >>> subsampling = { + ... "image": torch.arange(image_chunk_size * chunk_idx, image_chunk_size * (chunk_idx + 1)), + ... "audio": torch.arange(audio_chunk_size * chunk_idx, audio_chunk_size * (chunk_idx + 1)), + ... "label": None, + ... } + + >>> outputs = model(inputs=inputs, subsampled_output_points=subsampling) + >>> logits = outputs.logits + >>> list(logits["audio"].shape) + [1, 240] + + >>> list(logits["image"].shape) + [1, 6272, 3] + + >>> list(logits["label"].shape) + [1, 700] + ```""" + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + outputs = self.perceiver( + inputs=inputs, + attention_mask=attention_mask, + subsampled_output_points=subsampled_output_points, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + logits = outputs.logits if return_dict else outputs[0] + + loss = None + if labels is not None: + raise NotImplementedError("Multimodal autoencoding training is not yet supported") + + if not return_dict: + output = (logits,) + outputs[2:] + return ((loss,) + output) if loss is not None else output + + return PerceiverClassifierOutput( + loss=loss, + logits=logits, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + cross_attentions=outputs.cross_attentions, + ) + + +# Below: position encodings + + +def build_position_encoding( + position_encoding_type, + out_channels=None, + project_pos_dim=-1, + trainable_position_encoding_kwargs=None, + fourier_position_encoding_kwargs=None, +): + """ + Builds the position encoding. + + Args: + - out_channels: refers to the number of channels of the position encodings. + - project_pos_dim: if specified, will project the position encodings to this dimension. + + """ + + if position_encoding_type == "trainable": + if not trainable_position_encoding_kwargs: + raise ValueError("Make sure to pass trainable_position_encoding_kwargs") + output_pos_enc = PerceiverTrainablePositionEncoding(**trainable_position_encoding_kwargs) + elif position_encoding_type == "fourier": + # We don't use the index_dims argument, as this is only known during the forward pass + if not fourier_position_encoding_kwargs: + raise ValueError("Make sure to pass fourier_position_encoding_kwargs") + output_pos_enc = PerceiverFourierPositionEncoding(**fourier_position_encoding_kwargs) + else: + raise ValueError(f"Unknown position encoding type: {position_encoding_type}.") + + # Optionally, project the position encoding to a target dimension: + positions_projection = nn.Linear(out_channels, project_pos_dim) if project_pos_dim > 0 else nn.Identity() + + return output_pos_enc, positions_projection + + +# Below: Perceiver decoders + + +class PerceiverAbstractDecoder(nn.Module, metaclass=abc.ABCMeta): + """Perceiver abstract decoder.""" + + @abc.abstractmethod + def decoder_query(self, inputs, modality_sizes=None, inputs_without_pos=None, subsampled_points=None): + raise NotImplementedError + + @property + @abc.abstractmethod + def num_query_channels(self): + raise NotImplementedError + + @abc.abstractmethod + def forward(self, query, z, query_mask=None): + raise NotImplementedError + + +class PerceiverProjectionDecoder(PerceiverAbstractDecoder): + """ + Baseline projection decoder (no cross-attention). + + Args: + config ([`PerceiverConfig`]): + Model configuration. + """ + + def __init__(self, config): + super().__init__() + self.classifier = nn.Linear(config.d_latents, config.num_labels) + + def decoder_query(self, inputs, modality_sizes=None, inputs_without_pos=None, subsampled_points=None): + return None + + def forward( + self, query: torch.Tensor, z: torch.FloatTensor, query_mask: Optional[torch.FloatTensor] = None + ) -> torch.FloatTensor: + # (batch_size, num_latents, d_latents) -> (batch_size, d_latents) + z = torch.mean(z, dim=1) + # (batch_size, d_latents) -> (batch_size, config.num_labels) + logits = self.classifier(z) + return logits + + +class PerceiverBasicDecoder(PerceiverAbstractDecoder): + """ + Cross-attention-based decoder. This class can be used to decode the final hidden states of the latents using a + cross-attention operation, in which the latents produce keys and values. + + The shape of the output of this class depends on how one defines the output queries (also called decoder queries). + + Args: + config ([*PerceiverConfig*]): + Model configuration. + output_num_channels (`int`, *optional*): + The number of channels in the output. Will only be used in case *final_project* is set to `True`. + position_encoding_type (`str`, *optional*, defaults to "trainable"): + The type of position encoding to use. Can be either "trainable", "fourier", or "none". + output_index_dims (`int`, *optional*): + The number of dimensions of the output queries. Ignored if 'position_encoding_type' == 'none'. + num_channels (`int`, *optional*, defaults to 128): + The number of channels of the decoder queries. Ignored if 'position_encoding_type' == 'none'. + qk_channels (`int`, *optional*): + The number of channels of the queries and keys in the cross-attention layer. + v_channels (`int`, *optional*): + The number of channels of the values in the cross-attention layer. + num_heads (`int`, *optional*, defaults to 1): + The number of attention heads in the cross-attention layer. + widening_factor (`int`, *optional*, defaults to 1): + The widening factor of the cross-attention layer. + use_query_residual (`bool`, *optional*, defaults to `False`): + Whether to use a residual connection between the query and the output of the cross-attention layer. + concat_preprocessed_input (`bool`, *optional*, defaults to `False`): + Whether to concatenate the preprocessed input to the query. + final_project (`bool`, *optional*, defaults to `True`): + Whether to project the output of the cross-attention layer to a target dimension. + position_encoding_only (`bool`, *optional*, defaults to `False`): + Whether to only use this class to define output queries. + """ + + def __init__( + self, + config: PerceiverConfig, + output_num_channels: int, + position_encoding_type: Optional[str] = "trainable", + # The following 2 arguments are ignored if position_encoding_type == 'none': + output_index_dims: Optional[int] = None, + num_channels: Optional[int] = 128, + subsampled_index_dims: Optional[int] = None, + qk_channels: Optional[int] = None, + v_channels: Optional[int] = None, + num_heads: Optional[int] = 1, + widening_factor: Optional[int] = 1, + use_query_residual: Optional[bool] = False, + concat_preprocessed_input: Optional[bool] = False, + final_project: Optional[bool] = True, + position_encoding_only: Optional[bool] = False, + **position_encoding_kwargs, + ) -> None: + super().__init__() + + self.output_num_channels = output_num_channels + # If `none`, the decoder will not construct any position encodings. + # You should construct your own when querying the decoder. + self.output_position_encodings = None + self.position_encoding_type = position_encoding_type + self.position_encoding_kwargs = position_encoding_kwargs + if position_encoding_type != "none": + self.output_position_encodings, self.positions_projection = build_position_encoding( + position_encoding_type=position_encoding_type, **position_encoding_kwargs + ) + + self.output_index_dims = output_index_dims + self.num_channels = num_channels + if subsampled_index_dims is None: + subsampled_index_dims = output_index_dims + self.subsampled_index_dims = subsampled_index_dims + self.concat_preprocessed_input = concat_preprocessed_input + self.final_project = final_project + self.position_encoding_only = position_encoding_only + + # for multimodal autoencoding, we don't need the decoder cross-attention and final layer + # so then we will set position_encoding_only to True + if not self.position_encoding_only: + self.decoding_cross_attention = PerceiverLayer( + config, + is_cross_attention=True, + qk_channels=qk_channels, + v_channels=v_channels, + num_heads=num_heads, + q_dim=num_channels, + kv_dim=config.d_latents, + widening_factor=widening_factor, + use_query_residual=use_query_residual, + ) + self.final_layer = nn.Linear(num_channels, output_num_channels) if final_project else nn.Identity() + + @property + def num_query_channels(self) -> int: + if self.position_encoding_type == "none": # Queries come from elsewhere + raise ValueError( + "You cannot calculate number of decoder query channels when position_encoding_type is set to none" + ) + if self.position_encoding_only: + if "project_pos_dim" in self.position_encoding_kwargs: + return self.position_encoding_kwargs["project_pos_dim"] + return self.output_position_encodings.output_size() + if self.final_project: + return self.output_num_channels + return self.num_channels + + def decoder_query(self, inputs, modality_sizes=None, inputs_without_pos=None, subsampled_points=None): + if self.position_encoding_type == "none": # Queries come from elsewhere + raise ValueError("You cannot construct decoder queries when position_encoding_type is set to none") + if subsampled_points is not None: + # subsampled_points are the indices if the inputs would be flattened + # however, the inputs aren't flattened, that's why we use unravel_index + # to get the indices for the unflattened array + # unravel_index returns a tuple (x_idx, y_idx, ...) + # stack to get the [n, d] tensor of coordinates + indices = [torch.from_numpy(x) for x in np.unravel_index(subsampled_points.cpu(), self.output_index_dims)] + pos = torch.stack(indices, dim=1) + batch_size = inputs.shape[0] + # Map these coordinates to [-1, 1] + pos = -1 + 2 * pos / torch.tensor(self.output_index_dims)[None, :] + pos = torch.broadcast_to(pos[None], [batch_size, pos.shape[0], pos.shape[1]]) + # Construct the position encoding. + if self.position_encoding_type == "trainable": + pos_emb = self.output_position_encodings(batch_size) + elif self.position_encoding_type == "fourier": + pos_emb = self.output_position_encodings( + self.output_index_dims, batch_size=batch_size, device=inputs.device, dtype=inputs.dtype, pos=pos + ) + + # Optionally project them to a target dimension. + pos_emb = self.positions_projection(pos_emb) + pos_emb = torch.reshape(pos_emb, [pos_emb.shape[0], -1, pos_emb.shape[-1]]) + else: + batch_size = inputs.shape[0] + index_dims = inputs.shape[2:] + + # Construct the position encoding. + if self.position_encoding_type == "trainable": + pos_emb = self.output_position_encodings(batch_size) + elif self.position_encoding_type == "fourier": + pos_emb = self.output_position_encodings( + index_dims, batch_size, device=inputs.device, dtype=inputs.dtype + ) + + # Optionally project them to a target dimension. + pos_emb = self.positions_projection(pos_emb) + + if self.concat_preprocessed_input: + if inputs_without_pos is None: + raise ValueError("Value is required for inputs_without_pos if concat_preprocessed_input is True") + pos_emb = torch.cat([inputs_without_pos, pos_emb], dim=-1) + + return pos_emb + + def forward( + self, + query: torch.Tensor, + z: torch.FloatTensor, + query_mask: Optional[torch.FloatTensor] = None, + output_attentions: Optional[bool] = False, + ) -> PerceiverDecoderOutput: + # Cross-attention decoding. + # key, value: B x N x K; query: B x M x K + # Attention maps -> B x N x M + # Output -> B x M x K + cross_attentions = () if output_attentions else None + + layer_outputs = self.decoding_cross_attention( + query, + attention_mask=query_mask, + head_mask=None, + inputs=z, + inputs_mask=None, + output_attentions=output_attentions, + ) + output = layer_outputs[0] + + if output_attentions: + cross_attentions = cross_attentions + (layer_outputs[1],) + + logits = self.final_layer(output) + + return PerceiverDecoderOutput(logits=logits, cross_attentions=cross_attentions) + + +class PerceiverClassificationDecoder(PerceiverAbstractDecoder): + """ + Cross-attention based classification decoder. Light-weight wrapper of [`PerceiverBasicDecoder`] for logit output. + Will turn the output of the Perceiver encoder which is of shape (batch_size, num_latents, d_latents) to a tensor of + shape (batch_size, num_labels). The queries are of shape (batch_size, 1, num_labels). + + Args: + config ([`PerceiverConfig`]): + Model configuration. + """ + + def __init__(self, config, **decoder_kwargs): + super().__init__() + + self.num_labels = config.num_labels + self.decoder = PerceiverBasicDecoder( + config, + output_num_channels=self.num_labels, + output_index_dims=1, # Predict a single logit array. + **decoder_kwargs, + ) + + @property + def num_query_channels(self) -> int: + return self.decoder.num_query_channels + + def decoder_query(self, inputs, modality_sizes=None, inputs_without_pos=None, subsampled_points=None): + return self.decoder.decoder_query( + inputs, modality_sizes, inputs_without_pos, subsampled_points=subsampled_points + ) + + def forward( + self, + query: torch.Tensor, + z: torch.FloatTensor, + query_mask: Optional[torch.FloatTensor] = None, + output_attentions: Optional[bool] = False, + ) -> PerceiverDecoderOutput: + decoder_outputs = self.decoder(query, z, output_attentions=output_attentions) + + # B x 1 x num_classes -> B x num_classes + logits = decoder_outputs.logits[:, 0, :] + + return PerceiverDecoderOutput(logits=logits, cross_attentions=decoder_outputs.cross_attentions) + + +class PerceiverOpticalFlowDecoder(PerceiverAbstractDecoder): + """Cross-attention based optical flow decoder.""" + + def __init__(self, config, output_image_shape, output_num_channels=2, rescale_factor=100.0, **decoder_kwargs): + super().__init__() + + self.output_image_shape = output_image_shape + self.output_num_channels = output_num_channels + self.rescale_factor = rescale_factor + self.decoder = PerceiverBasicDecoder(config, output_num_channels=output_num_channels, **decoder_kwargs) + + @property + def num_query_channels(self) -> int: + return self.decoder.num_query_channels + + def decoder_query(self, inputs, modality_sizes=None, inputs_without_pos=None, subsampled_points=None): + if subsampled_points is not None: + raise ValueError("FlowDecoder doesn't support subsampling yet.") + return inputs + + def forward( + self, + query: torch.Tensor, + z: torch.FloatTensor, + query_mask: Optional[torch.FloatTensor] = None, + output_attentions: Optional[bool] = False, + ) -> PerceiverDecoderOutput: + decoder_outputs = self.decoder(query, z, output_attentions=output_attentions) + preds = decoder_outputs.logits + # Output flow and rescale. + preds /= self.rescale_factor + preds = preds.reshape([preds.shape[0]] + list(self.output_image_shape) + [preds.shape[-1]]) + return PerceiverDecoderOutput(logits=preds, cross_attentions=decoder_outputs.cross_attentions) + + +class PerceiverBasicVideoAutoencodingDecoder(PerceiverAbstractDecoder): + """ + Cross-attention based video-autoencoding decoder. Light-weight wrapper of [*PerceiverBasicDecoder*] with video + reshaping logic. + + Args: + config ([*PerceiverConfig*]): + Model configuration. + output_shape (`List[int]`): + Shape of the output as (batch_size, num_frames, height, width), excluding the channel dimension. + position_encoding_type (`str`): + The type of position encoding to use. Can be either "trainable", "fourier", or "none". + """ + + def __init__( + self, config: PerceiverConfig, output_shape: List[int], position_encoding_type: str, **decoder_kwargs + ) -> None: + super().__init__() + if len(output_shape) != 4: # B, T, H, W + raise ValueError(f"Expected rank 4 output_shape, got {output_shape}.") + # Build the decoder components: + self.output_shape = output_shape + self.output_num_channels = decoder_kwargs["output_num_channels"] + + self.decoder = PerceiverBasicDecoder( + config, + output_index_dims=self.output_shape[1:4], # T*H*W + position_encoding_type=position_encoding_type, + **decoder_kwargs, + ) + + @property + def num_query_channels(self) -> int: + return self.decoder.num_query_channels + + def decoder_query(self, inputs, modality_sizes=None, inputs_without_pos=None, subsampled_points=None): + return self.decoder.decoder_query( + inputs, + modality_sizes=modality_sizes, + inputs_without_pos=inputs_without_pos, + subsampled_points=subsampled_points, + ) + + def forward( + self, query: torch.Tensor, z: torch.FloatTensor, query_mask: Optional[torch.FloatTensor] = None + ) -> PerceiverDecoderOutput: + decoder_outputs = self.decoder(query, z) + logits = decoder_outputs.logits + + logits = torch.reshape(logits, self.output_shape + [logits.shape[-1]]) + return PerceiverDecoderOutput(logits=logits, cross_attentions=decoder_outputs.cross_attentions) + + +def restructure(modality_sizes: ModalitySizeType, inputs: torch.Tensor) -> Mapping[str, torch.Tensor]: + """ + Partitions a [B, N, C] tensor into tensors for each modality. + + Args: + modality_sizes + dict specifying the size of the modality + inputs: + input tensor + + Returns: + dict mapping name of modality to its associated tensor. + """ + outputs = {} + index = 0 + # Apply a predictable ordering to the modalities + for modality in sorted(modality_sizes.keys()): + size = modality_sizes[modality] + inp = inputs[:, index : index + size] + index += size + outputs[modality] = inp + return outputs + + +class PerceiverMultimodalDecoder(PerceiverAbstractDecoder): + """ + Multimodal decoding by composing uni-modal decoders. The *modalities* argument of the constructor is a dictionary + mapping modality name to the decoder of that modality. That decoder will be used to construct queries for that + modality. Modality-specific queries are padded with trainable modality-specific parameters, after which they are + concatenated along the time dimension. + + Next, there is a shared cross attention operation across all modalities. + + Args: + config ([*PerceiverConfig*]): + Model configuration. + modalities (`Dict[str, PerceiverAbstractDecoder]`): + Dictionary mapping modality name to the decoder of that modality. + num_outputs (`int`): + The number of outputs of the decoder. + output_num_channels (`int`): + The number of channels in the output. + min_padding_size (`int`, *optional*, defaults to 2): + The minimum padding size for all modalities. The final output will have num_channels equal to the maximum + channels across all modalities plus min_padding_size. + subsampled_index_dims (`Dict[str, PerceiverAbstractDecoder]`, *optional*): + Dictionary mapping modality name to the subsampled index dimensions to use for the decoder query of that + modality. + """ + + def __init__( + self, + config: PerceiverConfig, + modalities: Dict[str, PerceiverAbstractDecoder], + num_outputs: int, + output_num_channels: int, + min_padding_size: Optional[int] = 2, + subsampled_index_dims: Optional[Dict[str, PerceiverAbstractDecoder]] = None, + **decoder_kwargs, + ) -> None: + super().__init__() + self.modalities = nn.ModuleDict(modalities) + self.subsampled_index_dims = subsampled_index_dims + self.min_padding_size = min_padding_size + self.output_num_channels = output_num_channels + self.num_outputs = num_outputs + self.decoder = PerceiverBasicDecoder( + config, + output_index_dims=(num_outputs,), + output_num_channels=output_num_channels, + position_encoding_type="none", + num_channels=self.num_query_channels, + **decoder_kwargs, + ) + self.padding = nn.ParameterDict( + { + modality: nn.Parameter(torch.randn(1, self.num_query_channels - decoder.num_query_channels)) + for modality, decoder in modalities.items() + } + ) + + @property + def num_query_channels(self) -> int: + max_channel_size = max(decoder.num_query_channels for _, decoder in self.modalities.items()) + common_channel_size = max_channel_size + self.min_padding_size + return common_channel_size + + def decoder_query(self, inputs, modality_sizes, inputs_without_pos=None, subsampled_points=None): + # Partition the flat inputs among the different modalities + inputs = restructure(modality_sizes, inputs) + + # Obtain modality-specific decoders' queries + subsampled_points = subsampled_points or {} + + decoder_queries = {} + for modality, decoder in self.modalities.items(): + # Get input_without_pos for this modality if it exists. + input_without_pos = None + if inputs_without_pos is not None: + input_without_pos = inputs_without_pos.get(modality, None) + query = decoder.decoder_query( + inputs=inputs[modality], + modality_sizes=None, + inputs_without_pos=input_without_pos, + subsampled_points=subsampled_points.get(modality, None), + ) + decoder_queries[modality] = query + + # Pad all queries with trainable position encodings to make them have the same channels + + def embed(modality, x): + x = torch.reshape(x, [x.shape[0], np.prod(x.shape[1:-1]), x.shape[-1]]) + pos = self.padding[modality] + pos = torch.broadcast_to(pos, [x.shape[0], x.shape[1], self.num_query_channels - x.shape[2]]) + return torch.cat([x, pos], dim=2) + + # Apply a predictable ordering to the modalities + return torch.cat( + [embed(modality, decoder_queries[modality]) for modality in sorted(self.modalities.keys())], dim=1 + ) + + def forward( + self, + query: torch.Tensor, + z: torch.FloatTensor, + query_mask: Optional[torch.FloatTensor] = None, + output_attentions: Optional[bool] = False, + ) -> torch.Tensor: + # B x 1 x num_classes -> B x num_classes + decoder_outputs = self.decoder(query, z, output_attentions=output_attentions) + + return decoder_outputs + + +# Below: IO pre- and post-processor classes for Perceiver. +def space_to_depth(frames: torch.Tensor, temporal_block_size: int = 1, spatial_block_size: int = 1) -> torch.Tensor: + """ + Space to depth transform. Rearranges blocks of spatial data, into depth. + + This function assumes the channels to be first, but will place the channels last after transformation. + + Based on https://discuss.pytorch.org/t/is-there-any-layer-like-tensorflows-space-to-depth-function/3487/15. + """ + if len(frames.shape) == 4: + batch_size, num_channels, height, width = frames.shape + # split up dimensions (height by spatial_block_size, width by spatial_block_size) + frames = frames.view( + batch_size, + num_channels, + height // spatial_block_size, + spatial_block_size, + width // spatial_block_size, + spatial_block_size, + ) + # move blocks to last dimension: (batch_size, H//bs, W//bs, bs, bs, C) + frames = frames.permute(0, 2, 4, 3, 5, 1).contiguous() + # concatenate blocks along channel dimension: (batch_size, H//bs, W//bs, bs*bs*C) + frames = frames.view( + batch_size, + height // spatial_block_size, + width // spatial_block_size, + (spatial_block_size**2) * num_channels, + ) + return frames + elif len(frames.shape) == 5: + batch_size, time, num_channels, height, width = frames.shape + # split up dimensions (time by temporal_block_size, height by spatial_block_size, width by spatial_block_size) + frames = frames.view( + batch_size, + time // temporal_block_size, + temporal_block_size, + num_channels, + height // spatial_block_size, + spatial_block_size, + width // spatial_block_size, + spatial_block_size, + ) + # move blocks to last dimension: (batch_size, T//ts, H//bs, W//bs, ts, bs, bs, C) + frames = frames.permute(0, 1, 4, 6, 2, 5, 7, 3).contiguous() + # concatenate blocks along channel dimension: (batch_size, T//ts, H//bs, W//bs, ts*bs*bs*C) + frames = frames.view( + batch_size, + time // temporal_block_size, + height // spatial_block_size, + width // spatial_block_size, + temporal_block_size * (spatial_block_size**2) * num_channels, + ) + return frames + else: + raise ValueError( + "Frames should be of rank 4 (batch, channels, height, width)" + " or rank 5 (batch, time, channels, height, width)" + ) + + +class Conv2dSamePadding(nn.Conv2d): + """ + Conv2d layer with padding="same" support. Source: + https://gist.github.com/sumanmichael/4de9dee93f972d47c80c4ade8e149ea6 + """ + + def __init__(self, *args, **kwargs): + super(Conv2dSamePadding, self).__init__(*args, **kwargs) + self.zero_pad_2d = nn.ZeroPad2d( + reduce(__add__, [(k // 2 + (k - 2 * (k // 2)) - 1, k // 2) for k in self.kernel_size[::-1]]) + ) + + def forward(self, input): + return self._conv_forward(self.zero_pad_2d(input), self.weight, self.bias) + + +class Conv2DDownsample(nn.Module): + """Downsamples 4x by applying a 2D convolution and doing max pooling.""" + + def __init__( + self, + num_layers: int = 1, + in_channels: int = 3, + out_channels: int = 64, + use_batchnorm: bool = True, + ): + """ + Constructs a Conv2DDownsample model. + + Args: + in_channels (`int`, *optional*, defaults to 3): + The number of input channels. + out_channels (`int`, *optional*, defaults to 64): + The number of conv output channels. + use_batchnorm (`bool`, *optional*, defaults to `True`): + Whether to use batchnorm. + """ + super().__init__() + + self.conv = Conv2dSamePadding( + in_channels=in_channels, out_channels=out_channels, kernel_size=7, stride=2, bias=False + ) + self.batchnorm = nn.BatchNorm2d(num_features=out_channels) if use_batchnorm else nn.Identity() + self.relu = nn.ReLU() + self.max_pool = nn.MaxPool2d(kernel_size=3, stride=2) + + def forward(self, inputs: torch.Tensor) -> torch.Tensor: + out = self.conv(inputs) + out = self.batchnorm(out) + out = self.relu(out) + out = self.max_pool(out) + return out + + +def generate_fourier_features(pos, num_bands, max_resolution=(224, 224), concat_pos=True, sine_only=False): + """ + Generate a Fourier frequency position encoding with linear spacing. + + Args: + pos (`torch.LongTensor` of shape `(batch_size, sequence_length, dim)`): + The Tensor containing the position of n points in d dimensional space. + num_bands (`int`): + The number of frequency bands (K) to use. + max_resolution (`Tuple[int]`, *optional*, defaults to (224, 224)): + The maximum resolution (i.e. the number of pixels per dim). A tuple representing resolution for each dimension. + concat_pos (`bool`, *optional*, defaults to `True`): + Whether to concatenate the input position encoding to the Fourier features. + sine_only (`bool`, *optional*, defaults to `False`): + Whether to use a single phase (sin) or two (sin/cos) for each frequency band. + + Returns: + `torch.FloatTensor` of shape `(batch_size, sequence_length, n_channels)`: The Fourier position embeddings. If + `concat_pos` is `True` and `sine_only` is `False`, output dimensions are ordered as: [dim_1, dim_2, ..., dim_d, + sin(pi*f_1*dim_1), ..., sin(pi*f_K*dim_1), ..., sin(pi*f_1*dim_d), ..., sin(pi*f_K*dim_d), cos(pi*f_1*dim_1), + ..., cos(pi*f_K*dim_1), ..., cos(pi*f_1*dim_d), ..., cos(pi*f_K*dim_d)], where dim_i is pos[:, i] and f_k is the + kth frequency band. + """ + + batch_size = pos.shape[0] + + min_freq = 1.0 + # Nyquist frequency at the target resolution: + freq_bands = torch.stack( + [torch.linspace(start=min_freq, end=res / 2, steps=num_bands) for res in max_resolution], dim=0 + ) + + # Get frequency bands for each spatial dimension. + # Output is size [n, d * num_bands] + per_pos_features = pos[0, :, :][:, :, None] * freq_bands[None, :, :] + per_pos_features = torch.reshape(per_pos_features, [-1, np.prod(per_pos_features.shape[1:])]) + + if sine_only: + # Output is size [n, d * num_bands] + per_pos_features = torch.sin(np.pi * (per_pos_features)) + else: + # Output is size [n, 2 * d * num_bands] + per_pos_features = torch.cat( + [torch.sin(np.pi * per_pos_features), torch.cos(np.pi * per_pos_features)], dim=-1 + ) + # Concatenate the raw input positions. + if concat_pos: + # Adds d bands to the encoding. + per_pos_features = torch.cat([pos, per_pos_features.expand(batch_size, -1, -1)], dim=-1) + return per_pos_features + + +def build_linear_positions(index_dims, output_range=(-1.0, 1.0)): + """ + Generate an array of position indices for an N-D input array. + + Args: + index_dims (`List[int]`): + The shape of the index dimensions of the input array. + output_range (`Tuple[float]`, *optional*, defaults to `(-1.0, 1.0)`): + The min and max values taken by each input index dimension. + + Returns: + `torch.FloatTensor` of shape `(index_dims[0], index_dims[1], .., index_dims[-1], N)`. + """ + + def _linspace(n_xels_per_dim): + return torch.linspace(start=output_range[0], end=output_range[1], steps=n_xels_per_dim, dtype=torch.float32) + + dim_ranges = [_linspace(n_xels_per_dim) for n_xels_per_dim in index_dims] + array_index_grid = meshgrid(*dim_ranges, indexing="ij") + + return torch.stack(array_index_grid, dim=-1) + + +class PerceiverAbstractPositionEncoding(nn.Module, metaclass=abc.ABCMeta): + """Perceiver abstract position encoding.""" + + @property + @abc.abstractmethod + def num_dimensions(self) -> int: + raise NotImplementedError + + @abc.abstractmethod + def output_size(self, *args, **kwargs) -> int: + raise NotImplementedError + + @abc.abstractmethod + def forward(self, batch_size, pos): + raise NotImplementedError + + +class PerceiverTrainablePositionEncoding(PerceiverAbstractPositionEncoding): + """Trainable position encoding.""" + + def __init__(self, index_dims, num_channels=128): + super().__init__() + self._num_channels = num_channels + self._index_dims = index_dims + index_dim = np.prod(index_dims) + self.position_embeddings = nn.Parameter(torch.randn(index_dim, num_channels)) + + @property + def num_dimensions(self) -> int: + if isinstance(self._index_dims, int): + return 1 + return len(self._index_dims) + + def output_size(self, *args, **kwargs) -> int: + return self._num_channels + + def forward(self, batch_size: int) -> torch.Tensor: + position_embeddings = self.position_embeddings + + if batch_size is not None: + position_embeddings = position_embeddings.expand(batch_size, -1, -1) + return position_embeddings + + +def _check_or_build_spatial_positions(pos, index_dims, batch_size): + """ + Checks or builds spatial position features (x, y, ...). + + Args: + pos (`torch.FloatTensor`): + None, or an array of position features. If None, position features are built. Otherwise, their size is checked. + index_dims (`List[int]`): + An iterable giving the spatial/index size of the data to be featurized. + batch_size (`int`): + The batch size of the data to be featurized. + + Returns: + `torch.FloatTensor` of shape `(batch_size, prod(index_dims))` an array of position features. + """ + if pos is None: + pos = build_linear_positions(index_dims) + # equivalent to `torch.broadcast_to(pos[None], (batch_size,) + pos.shape)` + # but `torch.broadcast_to` cannot be converted to ONNX + pos = pos[None].expand((batch_size,) + pos.shape) + pos = torch.reshape(pos, [batch_size, np.prod(index_dims), -1]) + else: + # Just a warning label: you probably don't want your spatial features to + # have a different spatial layout than your pos coordinate system. + # But feel free to override if you think it'll work! + if pos.shape[-1] != len(index_dims): + raise ValueError("Spatial features have the wrong number of dimensions.") + return pos + + +class PerceiverFourierPositionEncoding(PerceiverAbstractPositionEncoding): + """Fourier (Sinusoidal) position encoding.""" + + def __init__(self, num_bands, max_resolution, concat_pos=True, sine_only=False): + super().__init__() + self.num_bands = num_bands + self.max_resolution = max_resolution + self.concat_pos = concat_pos + self.sine_only = sine_only + + @property + def num_dimensions(self) -> int: + return len(self.max_resolution) + + def output_size(self): + """Returns size of positional encodings last dimension.""" + num_dims = len(self.max_resolution) + encoding_size = self.num_bands * num_dims + if not self.sine_only: + encoding_size *= 2 + if self.concat_pos: + encoding_size += self.num_dimensions + + return encoding_size + + def forward( + self, + index_dims: List[int], + batch_size: int, + device: torch.device, + dtype: torch.dtype, + pos: torch.FloatTensor = None, + ) -> torch.FloatTensor: + pos = _check_or_build_spatial_positions(pos, index_dims, batch_size) + fourier_pos_enc = generate_fourier_features( + pos, + num_bands=self.num_bands, + max_resolution=self.max_resolution, + concat_pos=self.concat_pos, + sine_only=self.sine_only, + ).to(device=device, dtype=dtype) + return fourier_pos_enc + + +class AbstractPreprocessor(nn.Module): + @property + def num_channels(self) -> int: + """Returns size of preprocessor output.""" + raise NotImplementedError() + + +class PerceiverTextPreprocessor(AbstractPreprocessor): + """ + Text preprocessing for Perceiver Encoder. Can be used to embed `inputs` and add positional encodings. + + The dimensionality of the embeddings is determined by the `d_model` attribute of the configuration. + + Args: + config ([`PerceiverConfig`]): + Model configuration. + """ + + def __init__(self, config: PerceiverConfig) -> None: + super().__init__() + self.config = config + self.embeddings = nn.Embedding(num_embeddings=config.vocab_size, embedding_dim=config.d_model) + self.position_embeddings = nn.Embedding(config.max_position_embeddings, config.d_model) + + @property + def num_channels(self) -> int: + return self.config.d_model + + def forward(self, inputs: torch.LongTensor, pos: Optional[torch.Tensor] = None, network_input_is_1d: bool = True): + embeddings_without_pos = self.embeddings(inputs) + + seq_length = inputs.shape[1] + position_ids = torch.arange(0, seq_length, device=inputs.device) + embeddings = embeddings_without_pos + self.position_embeddings(position_ids) + + return embeddings, None, embeddings_without_pos + + +class PerceiverEmbeddingDecoder(nn.Module): + """ + Module to decode embeddings (for masked language modeling). + + Args: + config ([`PerceiverConfig`]): + Model configuration. + """ + + def __init__(self, config: PerceiverConfig) -> None: + super().__init__() + self.config = config + self.vocab_size = config.vocab_size + self.bias = nn.Parameter(torch.zeros(self.vocab_size)) + + def forward(self, hidden_states: torch.Tensor, embedding_layer: torch.Tensor) -> torch.Tensor: + batch_size, seq_len, d_model = hidden_states.shape + # Flatten batch dim + output = torch.matmul(hidden_states.reshape([-1, d_model]), embedding_layer.weight.transpose(0, 1)) + output = output + self.bias + + return output.reshape([batch_size, seq_len, self.vocab_size]) + + +class PerceiverMultimodalPostprocessor(nn.Module): + """ + Multimodal postprocessing for Perceiver. Can be used to combine modality-specific postprocessors into a single + postprocessor. + + Args: + modalities (`Mapping[str, PostprocessorType]`): + Dictionary mapping modality name to postprocessor class for that modality. + input_is_dict (`bool`, *optional*, defaults to `False`): + If True, input is assumed to be dictionary structured, and outputs keep the same dictionary shape. If + False, input is a tensor which is sliced up during postprocessing by *modality_sizes*. + """ + + def __init__(self, modalities: Mapping[str, PostprocessorType], input_is_dict: bool = False): + super().__init__() + self.modalities = nn.ModuleDict(modalities) + self.input_is_dict = input_is_dict + + def forward( + self, inputs: torch.Tensor, pos: Optional[torch.Tensor] = None, modality_sizes=None + ) -> Mapping[str, torch.Tensor]: + if not self.input_is_dict: + # Slice up modalities by their sizes. + if modality_sizes is None: + raise ValueError("Modality sizes should be specified if input is not a dictionary.") + inputs = restructure(modality_sizes=modality_sizes, inputs=inputs) + + outputs = { + modality: postprocessor(inputs[modality], pos=pos, modality_sizes=None) + for modality, postprocessor in self.modalities.items() + } + return outputs + + +class PerceiverClassificationPostprocessor(nn.Module): + """ + Classification postprocessing for Perceiver. Can be used to convert the decoder output to classification logits. + + Args: + config ([*PerceiverConfig*]): + Model configuration. + in_channels (`int`): + Number of channels in the input. + """ + + def __init__(self, config: PerceiverConfig, in_channels: int) -> None: + super().__init__() + self.classifier = nn.Linear(in_channels, config.num_labels) + + def forward(self, inputs, pos: Optional[torch.Tensor] = None, modality_sizes=None) -> torch.Tensor: + logits = self.classifier(inputs) + return logits[:, 0, :] + + +class PerceiverAudioPostprocessor(nn.Module): + """ + Audio postprocessing for Perceiver. Can be used to convert the decoder output to audio features. + + Args: + config ([*PerceiverConfig*]): + Model configuration. + in_channels (`int`): + Number of channels in the input. + postproc_type (`str`, *optional*, defaults to `"patches"`): + Postprocessor type to use. Currently, only "patches" is supported. + """ + + def __init__(self, config: PerceiverConfig, in_channels: int, postproc_type: str = "patches") -> None: + super().__init__() + + if postproc_type not in ("patches",): # to be supported: 'conv', 'patches', 'pixels' + raise ValueError("Invalid postproc_type!") + + # Architecture parameters: + self.classifier = nn.Linear(in_channels, config.samples_per_patch) + + def forward(self, inputs: torch.Tensor, pos: Optional[torch.Tensor] = None, modality_sizes=None) -> torch.Tensor: + logits = self.classifier(inputs) + return torch.reshape(logits, [inputs.shape[0], -1]) + + +class PerceiverProjectionPostprocessor(nn.Module): + """ + Projection postprocessing for Perceiver. Can be used to project the channels of the decoder output to a lower + dimension. + + Args: + in_channels (`int`): + Number of channels in the input. + out_channels (`int`): + Number of channels in the output. + """ + + def __init__(self, in_channels: int, out_channels: int) -> None: + super().__init__() + self.classifier = nn.Linear(in_channels, out_channels) + + def forward(self, inputs: torch.Tensor, pos: Optional[torch.Tensor] = None, modality_sizes=None) -> torch.Tensor: + logits = self.classifier(inputs) + return logits + + +class PerceiverImagePreprocessor(AbstractPreprocessor): + """ + Image preprocessing for Perceiver Encoder. + + Note: the *out_channels* argument refers to the output channels of a convolutional layer, if *prep_type* is set to + "conv1x1" or "conv". If one adds absolute position embeddings, one must make sure the *num_channels* of the + position encoding kwargs are set equal to the *out_channels*. + + Args: + config ([*PerceiverConfig*]): + Model configuration. + prep_type (`str`, *optional*, defaults to `"conv"`): + Preprocessing type. Can be "conv1x1", "conv", "patches", "pixels". + spatial_downsample (`int`, *optional*, defaults to 4): + Spatial downsampling factor. + temporal_downsample (`int`, *optional*, defaults to 1): + Temporal downsampling factor (only relevant in case a time dimension is present). + position_encoding_type (`str`, *optional*, defaults to `"fourier"`): + Position encoding type. Can be "fourier" or "trainable". + in_channels (`int`, *optional*, defaults to 3): + Number of channels in the input. + out_channels (`int`, *optional*, defaults to 64): + Number of channels in the output. + conv_after_patching (`bool`, *optional*, defaults to `False`): + Whether to apply a convolutional layer after patching. + conv_after_patching_in_channels (`int`, *optional*, defaults to 54): + Number of channels in the input of the convolutional layer after patching. + conv2d_use_batchnorm (`bool`, *optional*, defaults to `True`): + Whether to use batch normalization in the convolutional layer. + concat_or_add_pos (`str`, *optional*, defaults to `"concat"`): + How to concatenate the position encoding to the input. Can be "concat" or "add". + project_pos_dim (`int`, *optional*, defaults to -1): + Dimension of the position encoding to project to. If -1, no projection is applied. + **position_encoding_kwargs (`Dict`, *optional*): + Keyword arguments for the position encoding. + """ + + def __init__( + self, + config, + prep_type="conv", + spatial_downsample: int = 4, + temporal_downsample: int = 1, + position_encoding_type: str = "fourier", + in_channels: int = 3, + out_channels: int = 64, + conv_after_patching: bool = False, + conv_after_patching_in_channels: int = 54, # only relevant when conv_after_patching = True + conv2d_use_batchnorm: bool = True, + concat_or_add_pos: str = "concat", + project_pos_dim: int = -1, + **position_encoding_kwargs, + ): + super().__init__() + self.config = config + + if prep_type not in ("conv", "patches", "pixels", "conv1x1"): + raise ValueError(f"Prep_type {prep_type} is invalid") + + if concat_or_add_pos not in ["concat", "add"]: + raise ValueError(f"Invalid value {concat_or_add_pos} for concat_or_add_pos.") + + self.in_channels = in_channels + self.prep_type = prep_type + self.spatial_downsample = spatial_downsample + self.temporal_downsample = temporal_downsample + self.position_encoding_type = position_encoding_type + self.concat_or_add_pos = concat_or_add_pos + self.conv_after_patching = conv_after_patching + self.out_channels = out_channels + + if self.prep_type == "conv": + # Downsampling with conv is currently restricted + convnet_num_layers = math.log(spatial_downsample, 4) + convnet_num_layers_is_int = convnet_num_layers == np.round(convnet_num_layers) + if not convnet_num_layers_is_int or temporal_downsample != 1: + raise ValueError( + "Only powers of 4 expected for spatial and 1 expected for temporal downsampling with conv." + ) + self.convnet = Conv2DDownsample( + in_channels=in_channels, + num_layers=int(convnet_num_layers), + out_channels=out_channels, + use_batchnorm=conv2d_use_batchnorm, + ) + + elif self.prep_type == "conv1x1": + if temporal_downsample != 1: + raise ValueError("Conv1x1 does not downsample in time.") + self.convnet_1x1 = nn.Conv2d( + in_channels=in_channels, + out_channels=out_channels, + kernel_size=(1, 1), + # spatial_downsample is unconstrained for 1x1 convolutions. + stride=(spatial_downsample, spatial_downsample), + ) + + # Position embeddings + self.project_pos_dim = project_pos_dim + self.position_embeddings, self.positions_projection = build_position_encoding( + position_encoding_type=position_encoding_type, + out_channels=out_channels, + project_pos_dim=project_pos_dim, + **position_encoding_kwargs, + ) + + # Optional convolutional layer after patches. + self.conv_after_patches = ( + nn.Linear(conv_after_patching_in_channels, self.out_channels) if conv_after_patching else nn.Identity() + ) + + @property + def num_channels(self) -> int: + # Let's assume that the number of resolutions (in the context of image preprocessing) + # of the input data is 2 or 3 depending on whether we are processing image or video respectively. + # In this case, for convenience, we will declare is_temporal variable, + # which will show whether the data has a temporal dimension or not. + is_temporal = self.position_embeddings.num_dimensions > 2 + + # position embedding + if self.project_pos_dim > 0: + pos_dim = self.project_pos_dim + else: + pos_dim = self.position_embeddings.output_size() + if self.concat_or_add_pos == "add": + return pos_dim + + # inputs + if self.conv_after_patching or self.prep_type in ("conv1x1", "conv"): + inp_dim = self.out_channels + elif self.prep_type == "pixels": + inp_dim = self.in_channels + if not is_temporal: + inp_dim = math.ceil(inp_dim / self.spatial_downsample) + elif self.prep_type == "patches": + if self.conv_after_patching: + inp_dim = self.out_channels + else: + inp_dim = self.in_channels * self.spatial_downsample**2 + if is_temporal: + inp_dim *= self.temporal_downsample + + return inp_dim + pos_dim + + def _build_network_inputs(self, inputs: torch.Tensor, network_input_is_1d: bool = True): + """ + Construct the final input, including position encoding. + + This method expects the inputs to always have channels as last dimension. + + """ + batch_size = inputs.shape[0] + index_dims = inputs.shape[1:-1] + indices = np.prod(index_dims) + + # Flatten input features to a 1D index dimension if necessary. + if len(inputs.shape) > 3 and network_input_is_1d: + inputs = torch.reshape(inputs, [batch_size, indices, -1]) + + # Construct the position encoding. + if self.position_encoding_type == "trainable": + pos_enc = self.position_embeddings(batch_size) + elif self.position_encoding_type == "fourier": + pos_enc = self.position_embeddings(index_dims, batch_size, device=inputs.device, dtype=inputs.dtype) + + # Optionally project them to a target dimension. + pos_enc = self.positions_projection(pos_enc) + + if not network_input_is_1d: + # Reshape pos to match the input feature shape + # if the network takes non-1D inputs + sh = inputs.shape + pos_enc = torch.reshape(pos_enc, list(sh)[:-1] + [-1]) + if self.concat_or_add_pos == "concat": + inputs_with_pos = torch.cat([inputs, pos_enc], dim=-1) + elif self.concat_or_add_pos == "add": + inputs_with_pos = inputs + pos_enc + return inputs_with_pos, inputs + + def forward(self, inputs: torch.Tensor, pos: Optional[torch.Tensor] = None, network_input_is_1d: bool = True): + if self.prep_type == "conv": + # Convnet image featurization. + # Downsamples spatially by a factor of 4 + inputs = self.convnet(inputs) + + elif self.prep_type == "conv1x1": + # map inputs to self.out_channels + inputs = self.convnet_1x1(inputs) + + elif self.prep_type == "pixels": + # if requested, downsamples in the crudest way + if inputs.ndim == 4: + inputs = inputs[:: self.spatial_downsample, :: self.spatial_downsample] + elif inputs.ndim == 5: + inputs = inputs[ + :, :: self.temporal_downsample, :, :: self.spatial_downsample, :: self.spatial_downsample + ] + else: + raise ValueError("Unsupported data format for pixels.") + + elif self.prep_type == "patches": + # Space2depth featurization. + # Video: B x T x C x H x W + inputs = space_to_depth( + inputs, temporal_block_size=self.temporal_downsample, spatial_block_size=self.spatial_downsample + ) + + if inputs.ndim == 5 and inputs.shape[1] == 1: + # for flow + inputs = inputs.squeeze(dim=1) + + # Optionally apply conv layer. + inputs = self.conv_after_patches(inputs) + + if self.prep_type != "patches": + # move channels to last dimension, as the _build_network_inputs method below expects this + if inputs.ndim == 4: + inputs = inputs.permute(0, 2, 3, 1) + elif inputs.ndim == 5: + inputs = inputs.permute(0, 1, 3, 4, 2) + else: + raise ValueError("Unsupported data format for conv1x1.") + + inputs, inputs_without_pos = self._build_network_inputs(inputs, network_input_is_1d) + modality_sizes = None # Size for each modality, only needed for multimodal + + return inputs, modality_sizes, inputs_without_pos + + +class PerceiverOneHotPreprocessor(AbstractPreprocessor): + """ + One-hot preprocessor for Perceiver Encoder. Can be used to add a dummy index dimension to the input. + + Args: + config ([`PerceiverConfig`]): + Model configuration. + """ + + def __init__(self, config: PerceiverConfig) -> None: + super().__init__() + self.config: PerceiverConfig = config + + @property + def num_channels(self) -> int: + return self.config.num_labels + + def forward(self, inputs: torch.Tensor, pos: Optional[torch.Tensor] = None, network_input_is_1d: bool = True): + # Add a dummy index dimension. + inputs = inputs[:, None, :] + + # No position encodings, so the 1st (input) and 3rd (inputs_without_pos) + # outputs are identical. + return inputs, None, inputs + + +class PerceiverAudioPreprocessor(AbstractPreprocessor): + """ + Audio preprocessing for Perceiver Encoder. + + Args: + config ([*PerceiverConfig*]): + Model configuration. + prep_type (`str`, *optional*, defaults to `"patches"`): + Preprocessor type to use. Only "patches" is supported. + samples_per_patch (`int`, *optional*, defaults to 96): + Number of samples per patch. + position_encoding_type (`str`, *optional*, defaults to `"fourier"`): + Type of position encoding to use. Can be "trainable" or "fourier". + concat_or_add_pos (`str`, *optional*, defaults to `"concat"`): + How to concatenate the position encoding to the input. Can be "concat" or "add". + out_channels (`int`, *optional*, defaults to 64): + Number of channels in the output. + project_pos_dim (`int`, *optional*, defaults to -1): + Dimension of the position encoding to project to. If -1, no projection is applied. + **position_encoding_kwargs (`Dict`, *optional*): + Keyword arguments for the position encoding. + """ + + def __init__( + self, + config, + prep_type: str = "patches", + samples_per_patch: int = 96, + position_encoding_type: str = "fourier", + concat_or_add_pos: str = "concat", + out_channels=64, + project_pos_dim=-1, + **position_encoding_kwargs, + ): + super().__init__() + self.config = config + + if prep_type not in ("patches",): + raise ValueError(f"Prep_type {prep_type} is invalid, can only be 'patches'.") + + if concat_or_add_pos not in ["concat", "add"]: + raise ValueError(f"Concat_or_pos {concat_or_add_pos} is invalid, can only be 'concat' or 'add'.") + + self.samples_per_patch = samples_per_patch + self.position_encoding_type = position_encoding_type + self.concat_or_add_pos = concat_or_add_pos + self.project_pos_dim = project_pos_dim + + # Position embeddings + self.position_embeddings, self.positions_projection = build_position_encoding( + position_encoding_type=position_encoding_type, + out_channels=out_channels, + project_pos_dim=project_pos_dim, + **position_encoding_kwargs, + ) + + @property + def num_channels(self) -> int: + # position embedding + if self.project_pos_dim > 0: + pos_dim = self.project_pos_dim + else: + pos_dim = self.position_embeddings.output_size() + if self.concat_or_add_pos == "add": + return pos_dim + return self.samples_per_patch + pos_dim + + def _build_network_inputs(self, inputs): + """Construct the final input, including position encoding.""" + batch_size = inputs.shape[0] + index_dims = inputs.shape[1:-1] + + # Construct the position encoding. + if self.position_encoding_type == "trainable": + pos_enc = self.position_embeddings(batch_size) + elif self.position_encoding_type == "fourier": + pos_enc = self.position_embeddings(index_dims, batch_size, device=inputs.device, dtype=inputs.dtype) + + # Optionally project them to a target dimension. + pos_enc = self.positions_projection(pos_enc) + + if self.concat_or_add_pos == "concat": + inputs_with_pos = torch.cat([inputs, pos_enc], dim=-1) + elif self.concat_or_add_pos == "add": + inputs_with_pos = inputs + pos_enc + + return inputs_with_pos, inputs + + def forward(self, inputs: torch.Tensor, pos: Optional[torch.Tensor] = None, network_input_is_1d: bool = True): + inputs = torch.reshape(inputs, [inputs.shape[0], -1, self.samples_per_patch]) + + inputs, inputs_without_pos = self._build_network_inputs(inputs) + modality_sizes = None # Size for each modality, only needed for multimodal + + return inputs, modality_sizes, inputs_without_pos + + +class PerceiverMultimodalPreprocessor(AbstractPreprocessor): + """ + Multimodal preprocessing for Perceiver Encoder. + + Inputs for each modality are preprocessed, then padded with trainable position embeddings to have the same number + of channels. + + Args: + modalities (`Mapping[str, PreprocessorType]`): + Dict mapping modality name to preprocessor. + mask_probs (`Dict[str, float]`): + Dict mapping modality name to masking probability of that modality. + min_padding_size (`int`, *optional*, defaults to 2): + The minimum padding size for all modalities. The final output will have num_channels equal to the maximum + channels across all modalities plus min_padding_size. + """ + + def __init__( + self, + modalities: Mapping[str, PreprocessorType], + mask_probs: Optional[Mapping[str, float]] = None, + min_padding_size: int = 2, + ): + super().__init__() + self.modalities = nn.ModuleDict(modalities) + self.min_padding_size = min_padding_size + self.mask_probs = mask_probs if mask_probs is not None else {} + self.padding = nn.ParameterDict( + { + modality: nn.Parameter(torch.randn(1, self.num_channels - preprocessor.num_channels)) + for modality, preprocessor in modalities.items() + } + ) + self.mask = nn.ParameterDict( + {modality: nn.Parameter(torch.randn(1, self.num_channels)) for modality, _ in self.mask_probs.items()} + ) + + @property + def num_channels(self) -> int: + max_channel_size = max(processor.num_channels for _, processor in self.modalities.items()) + common_channel_size = max_channel_size + self.min_padding_size + return common_channel_size + + def forward( + self, inputs: Mapping[str, torch.Tensor], pos: Optional[torch.Tensor] = None, network_input_is_1d: bool = True + ) -> PreprocessorOutputType: + padded = {} + modality_sizes = {} + inputs_without_pos = {} + for modality, preprocessor in self.modalities.items(): + # preprocess each modality using the respective preprocessor. + output, _, inputs_without_pos[modality] = preprocessor( + inputs[modality], pos=pos, network_input_is_1d=network_input_is_1d + ) + + # pad to the same common_channel_size. + batch_size, num_samples, num_channels = output.shape + pos_enc = self.padding[modality].expand(batch_size, -1, -1) + + padding = torch.broadcast_to( + pos_enc, + [batch_size, num_samples, self.num_channels - num_channels], + ) + output_padded = torch.cat([output, padding], dim=2) + + # mask if required + if modality in self.mask_probs: + mask_token = self.mask[modality].expand(batch_size, -1, -1) + mask_prob = self.mask_probs[modality] + mask = torch.bernoulli(torch.full([batch_size, num_samples], mask_prob)) + mask = torch.unsqueeze(mask, dim=2).to(mask_token.device) + output_padded = (1 - mask) * output_padded + mask * mask_token + + padded[modality] = output_padded + modality_sizes[modality] = output_padded.shape[1] + + # Apply a predictable ordering to the modalities + padded_ls = [padded[k] for k in sorted(padded.keys())] + + # Finally, concatenate along the time dimension + final_inputs = torch.cat(padded_ls, dim=1) + + return final_inputs, modality_sizes, inputs_without_pos