diff --git "a/llmeval-env/lib/python3.10/site-packages/transformers/models/longt5/modeling_flax_longt5.py" "b/llmeval-env/lib/python3.10/site-packages/transformers/models/longt5/modeling_flax_longt5.py"
new file mode 100644--- /dev/null
+++ "b/llmeval-env/lib/python3.10/site-packages/transformers/models/longt5/modeling_flax_longt5.py"
@@ -0,0 +1,2447 @@
+# coding=utf-8
+# Copyright 2022 LongT5 Authors and HuggingFace Inc. team.
+#
+# 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.
+""" Flax LongT5 model."""
+
+
+import copy
+from typing import Any, Callable, List, Optional, Tuple
+
+import flax.linen as nn
+import jax
+import jax.numpy as jnp
+import numpy as np
+from flax.core.frozen_dict import FrozenDict, freeze, unfreeze
+from flax.linen import combine_masks, make_causal_mask
+from flax.linen import partitioning as nn_partitioning
+from flax.linen.attention import dot_product_attention_weights
+from flax.traverse_util import flatten_dict, unflatten_dict
+from jax.random import PRNGKey
+
+from ...modeling_flax_outputs import (
+    FlaxBaseModelOutput,
+    FlaxBaseModelOutputWithPastAndCrossAttentions,
+    FlaxCausalLMOutputWithCrossAttentions,
+    FlaxSeq2SeqLMOutput,
+    FlaxSeq2SeqModelOutput,
+)
+from ...modeling_flax_utils import (
+    ACT2FN,
+    FlaxPreTrainedModel,
+    append_call_sample_docstring,
+    append_replace_return_docstrings,
+    overwrite_call_docstring,
+)
+from ...utils import add_start_docstrings, add_start_docstrings_to_model_forward, logging, replace_return_docstrings
+from .configuration_longt5 import LongT5Config
+
+
+logger = logging.get_logger(__name__)
+
+_CHECKPOINT_FOR_DOC = "google/long-t5-local-base"
+_CONFIG_FOR_DOC = "LongT5Config"
+
+remat = nn_partitioning.remat
+
+
+# Copied from transformers.models.bart.modeling_flax_bart.shift_tokens_right
+def shift_tokens_right(input_ids: jnp.ndarray, pad_token_id: int, decoder_start_token_id: int) -> jnp.ndarray:
+    """
+    Shift input ids one token to the right.
+    """
+    shifted_input_ids = jnp.zeros_like(input_ids)
+    shifted_input_ids = shifted_input_ids.at[:, 1:].set(input_ids[:, :-1])
+    shifted_input_ids = shifted_input_ids.at[:, 0].set(decoder_start_token_id)
+
+    shifted_input_ids = jnp.where(shifted_input_ids == -100, pad_token_id, shifted_input_ids)
+    return shifted_input_ids
+
+
+def _pad_to_multiple(x: jnp.ndarray, block_len: int, axis: int, pad_value: int = 0) -> jnp.ndarray:
+    """Pad an array so that a sequence length will be a multiple of `block_len`"""
+    pad_len = -x.shape[axis] % block_len
+    pad = [(0, 0)] * x.ndim
+    pad[axis] = (0, pad_len)
+    x = jnp.pad(x, pad_width=pad, mode="constant", constant_values=pad_value)
+    return x
+
+
+def _split_into_blocks(x: jnp.ndarray, block_len: int, axis: int) -> jnp.ndarray:
+    """Split an input array into blocks of a given `block_len` along the given `axis`. If the dimension length
+    is not a multiple of `block_len`, it will be padded first with selected `pad_value`.
+    """
+    # pad tensor to multiple of block_len
+    if x.shape[axis] % block_len != 0:
+        x = _pad_to_multiple(x, block_len, axis, pad_value=0)
+    num_blocks = x.shape[axis] // block_len
+    output_shape = x.shape[:axis] + (num_blocks, block_len) + x.shape[(axis + 1) :]
+    return x.reshape(output_shape)
+
+
+def _concatenate_3_blocks(x: jnp.ndarray, block_axis: int, sequence_axis: int, pad_value: int = 0) -> jnp.ndarray:
+    """Concatenate three consecutive blocks for each input block for local attentiont.
+    For more information, see: https://arxiv.org/pdf/2112.07916.pdf.
+    """
+    num_blocks = x.shape[block_axis]
+
+    pad = [(0, 0)] * x.ndim
+    pad[block_axis] = (1, 1)
+    # [batch_size, num_blocks, block_len] -> [batch_size, num_blocks + 2, block_len]
+    x = jnp.pad(x, pad_width=pad, mode="constant", constant_values=pad_value)
+
+    blocks_list: List[np.array] = []
+    for i in range(3):
+        # We use indexing approach here:
+        # https://numpy.org/doc/stable/user/basics.indexing.html#dealing-with-variable-numbers-of-indices-within-programs
+        indices = [slice(0, None)] * x.ndim
+        indices[block_axis] = slice(i, i + num_blocks)
+        indices = tuple(indices)
+        blocks_list.append(x[indices])
+    return jnp.concatenate(blocks_list, axis=sequence_axis)  # [batch_size, num_blocks, 3 * block_len, ...]
+
+
+def _make_3block_relative_position_ids(block_len: int) -> jnp.ndarray:
+    """Makes 3-blocked relative position ids for local attention."""
+    position_ids = jnp.arange(3 * block_len, dtype=jnp.int32)
+    center_position_ids = position_ids[block_len:-block_len]
+    relative_position_ids = position_ids[None, :] - center_position_ids[:, None]  # [block_len, 3 * block_len]
+    return relative_position_ids
+
+
+def _mask_local_attention_mask(local_attention_mask: np.ndarray, block_len: int) -> jnp.ndarray:
+    """Mask local attention mask to enforce that tokens are not allowed to attend tokens farther than ``local_radius."""
+    relative_position_ids = _make_3block_relative_position_ids(block_len)
+    locality_mask = jnp.abs(relative_position_ids) < block_len
+    locality_mask = locality_mask[None, None, :, :]
+    return jnp.logical_and(local_attention_mask, locality_mask)
+
+
+def _get_local_attention_mask(attention_mask: np.ndarray, block_len: int) -> jnp.ndarray:
+    """Prepare attention mask to be applied for a local attention."""
+    # [batch_size, num_blocks, block_len]
+    _blocked_attention_mask = _split_into_blocks(attention_mask, block_len, axis=1)
+    # [batch_size, num_block, 3 * block_len]
+    _3blocked_attention_mask = _concatenate_3_blocks(_blocked_attention_mask, block_axis=1, sequence_axis=2)
+
+    _blocked_attention_mask = _blocked_attention_mask[..., None]
+    _3blocked_attention_mask = _3blocked_attention_mask[..., None, :]
+    # [batch_size, num_block, block_len, 3 * block_len]
+    local_attention_mask = jnp.logical_and(_blocked_attention_mask, _3blocked_attention_mask)
+    local_attention_mask = _mask_local_attention_mask(local_attention_mask, block_len)
+    # [batch_size, 1, num_block, block_len, 3 * block_len]
+    return local_attention_mask[:, None, ...]
+
+
+def _make_global_fixed_block_ids(attention_mask: np.ndarray, global_block_size: int) -> Tuple[jnp.ndarray, np.ndarray]:
+    """Obtain the "fixed block" global id corresponding to each input token.
+
+    This implementation is a simlified version of the original Flaxformr implementation adopted from:
+    https://github.com/google/flaxformer/blob/main/flaxformer/architectures/longt5/long_attention.py.
+
+    In our scenario, as we use this strategy only for a decoder, orphan tokens, i.e. those tokens which do not make for
+    the whole fixed block, are assigned to the preceding block.
+
+    Padding tokens from the original sequence are represented by -1.
+    """
+    batch_size, seq_len = attention_mask.shape[:2]
+
+    def handle_orphan_tokens(block_ids: np.ndarray) -> jnp.ndarray:
+        block_ends = (jnp.arange(seq_len) % global_block_size) == global_block_size - 1
+        true_block_ends = jnp.logical_and(block_ends, block_ids >= 0)
+        full_blocks = true_block_ends.sum(-1)[..., None]
+        block_ids = jnp.minimum(block_ids, full_blocks - 1)
+        return block_ids
+
+    fixed_block_mask = jnp.ones_like(attention_mask) / global_block_size
+    fixed_block_mask = jnp.cumsum(fixed_block_mask, axis=1) - fixed_block_mask
+    mask = jnp.where(attention_mask != 0.0, 1.0, -1000.0)
+    global_block_ids = jnp.maximum(
+        jnp.floor(mask + fixed_block_mask - 1.0), jnp.array(-1.0, dtype=attention_mask.dtype)
+    )
+    # set padding tokens to -1
+    global_block_ids = (global_block_ids * attention_mask) + (attention_mask - 1)
+    # [batch_size, seq_len]
+    global_block_ids = handle_orphan_tokens(global_block_ids)
+    num_globals = seq_len // global_block_size
+
+    # [batch_size, seq_len // global_block_size]
+    if num_globals > 0:
+        _sequence_block_ids_max = jnp.repeat(global_block_ids.max(axis=-1)[:, None], repeats=num_globals, axis=1)
+    else:
+        _sequence_block_ids_max = jnp.zeros((batch_size, 0), dtype=global_block_ids.dtype)
+    global_segment_ids = jnp.cumsum(jnp.ones((batch_size, num_globals)), axis=-1) - 1
+    global_segment_ids = jnp.where(global_segment_ids <= _sequence_block_ids_max, 1, 0)
+    return global_block_ids, global_segment_ids
+
+
+def _make_side_relative_position_ids(attention_mask: np.ndarray, global_block_size: int) -> np.ndarray:
+    """Create the relative position tensor for local -> global attention."""
+    block_ids, global_segment_ids = _make_global_fixed_block_ids(attention_mask, global_block_size)
+    global_seq_len = global_segment_ids.shape[-1]
+    global_positions = jnp.arange(global_seq_len)
+    side_relative_position = global_positions - block_ids[..., None]
+    return side_relative_position
+
+
+def _create_global_aggregates(hidden_states: np.ndarray, block_ids: np.ndarray, global_seq_len: int) -> np.ndarray:
+    """Compute individual block aggregates by summing over individual blocks."""
+    # (batch..., seq_len, global_seq_len))
+    one_hot_block_ids = jax.nn.one_hot(block_ids, global_seq_len)
+    return jnp.einsum("...nd,...ng->...gd", hidden_states, one_hot_block_ids)
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5LayerNorm with T5->LongT5
+class FlaxLongT5LayerNorm(nn.Module):
+    hidden_size: int
+    dtype: jnp.dtype = jnp.float32
+    eps: float = 1e-6
+    weight_init: Callable[..., np.ndarray] = jax.nn.initializers.ones
+
+    def setup(self):
+        self.weight = self.param("weight", self.weight_init, (self.hidden_size,))
+
+    def __call__(self, hidden_states):
+        """
+        Construct a layernorm module in the LongT5 style; No bias and no subtraction of mean.
+        """
+        # layer norm should always be calculated in float32
+        variance = jnp.power(hidden_states.astype("f4"), 2).mean(axis=-1, keepdims=True)
+        hidden_states = hidden_states / jnp.sqrt(variance + self.eps)
+
+        return self.weight * hidden_states
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5DenseActDense with T5->LongT5
+class FlaxLongT5DenseActDense(nn.Module):
+    config: LongT5Config
+    dtype: jnp.dtype = jnp.float32
+
+    def setup(self):
+        wi_init_std = self.config.initializer_factor * (self.config.d_model**-0.5)
+        wo_init_std = self.config.initializer_factor * (self.config.d_ff**-0.5)
+
+        self.wi = nn.Dense(
+            self.config.d_ff,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(wi_init_std),
+            dtype=self.dtype,
+        )
+        self.wo = nn.Dense(
+            self.config.d_model,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(wo_init_std),
+            dtype=self.dtype,
+        )
+        self.dropout = nn.Dropout(self.config.dropout_rate)
+        self.act = ACT2FN[self.config.dense_act_fn]
+
+    def __call__(self, hidden_states, deterministic=True):
+        hidden_states = self.wi(hidden_states)
+        hidden_states = self.act(hidden_states)
+        hidden_states = self.dropout(hidden_states, deterministic=deterministic)
+        hidden_states = self.wo(hidden_states)
+        return hidden_states
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5DenseGatedActDense with T5->LongT5
+class FlaxLongT5DenseGatedActDense(nn.Module):
+    config: LongT5Config
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        wi_init_std = self.config.initializer_factor * (self.config.d_model**-0.5)
+        wo_init_std = self.config.initializer_factor * (self.config.d_ff**-0.5)
+
+        self.wi_0 = nn.Dense(
+            self.config.d_ff,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(wi_init_std),
+            dtype=self.dtype,
+        )
+        self.wi_1 = nn.Dense(
+            self.config.d_ff,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(wi_init_std),
+            dtype=self.dtype,
+        )
+        self.wo = nn.Dense(
+            self.config.d_model,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(wo_init_std),
+            dtype=self.dtype,
+        )
+        self.dropout = nn.Dropout(self.config.dropout_rate)
+        self.act = ACT2FN[self.config.dense_act_fn]
+
+    def __call__(self, hidden_states, deterministic):
+        hidden_gelu = self.act(self.wi_0(hidden_states))
+        hidden_linear = self.wi_1(hidden_states)
+        hidden_states = hidden_gelu * hidden_linear
+        hidden_states = self.dropout(hidden_states, deterministic=deterministic)
+        hidden_states = self.wo(hidden_states)
+        return hidden_states
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5LayerFF with T5->LongT5
+class FlaxLongT5LayerFF(nn.Module):
+    config: LongT5Config
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        if self.config.is_gated_act:
+            self.DenseReluDense = FlaxLongT5DenseGatedActDense(self.config, dtype=self.dtype)
+        else:
+            self.DenseReluDense = FlaxLongT5DenseActDense(self.config, dtype=self.dtype)
+
+        self.layer_norm = FlaxLongT5LayerNorm(
+            self.config.d_model, eps=self.config.layer_norm_epsilon, dtype=self.dtype
+        )
+        self.dropout = nn.Dropout(self.config.dropout_rate)
+
+    def __call__(self, hidden_states, deterministic=True):
+        forwarded_states = self.layer_norm(hidden_states)
+        forwarded_states = self.DenseReluDense(forwarded_states, deterministic=deterministic)
+        hidden_states = hidden_states + self.dropout(forwarded_states, deterministic=deterministic)
+        return hidden_states
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5Attention with T5->LongT5
+class FlaxLongT5Attention(nn.Module):
+    config: LongT5Config
+    has_relative_attention_bias: bool = False
+    causal: bool = False
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        self.relative_attention_num_buckets = self.config.relative_attention_num_buckets
+        self.relative_attention_max_distance = self.config.relative_attention_max_distance
+        self.d_model = self.config.d_model
+        self.key_value_proj_dim = self.config.d_kv
+        self.n_heads = self.config.num_heads
+        self.dropout = self.config.dropout_rate
+        self.inner_dim = self.n_heads * self.key_value_proj_dim
+
+        q_init_std = self.config.initializer_factor * ((self.inner_dim * self.key_value_proj_dim) ** -0.5)
+        kv_init_std = self.config.initializer_factor * (self.inner_dim**-0.5)
+        o_init_std = self.config.initializer_factor * (self.inner_dim**-0.5)
+
+        self.q = nn.Dense(
+            self.inner_dim,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(q_init_std),
+            dtype=self.dtype,
+        )
+        self.k = nn.Dense(
+            self.inner_dim,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(kv_init_std),
+            dtype=self.dtype,
+        )
+        self.v = nn.Dense(
+            self.inner_dim,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(kv_init_std),
+            dtype=self.dtype,
+        )
+        self.o = nn.Dense(
+            self.d_model,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(o_init_std),
+            dtype=self.dtype,
+        )
+
+        if self.has_relative_attention_bias:
+            self.relative_attention_bias = nn.Embed(
+                self.relative_attention_num_buckets,
+                self.n_heads,
+                embedding_init=jax.nn.initializers.normal(kv_init_std),
+                dtype=self.dtype,
+            )
+
+    @staticmethod
+    def _relative_position_bucket(relative_position, bidirectional=True, num_buckets=32, max_distance=128):
+        """
+        Adapted from Mesh Tensorflow:
+        https://github.com/tensorflow/mesh/blob/0cb87fe07da627bf0b7e60475d59f95ed6b5be3d/mesh_tensorflow/transformer/transformer_layers.py#L593
+
+        Translate relative position to a bucket number for relative attention. The relative position is defined as
+        memory_position - query_position, i.e. the distance in tokens from the attending position to the attended-to
+        position. If bidirectional=False, then positive relative positions are invalid. We use smaller buckets for
+        small absolute relative_position and larger buckets for larger absolute relative_positions. All relative
+        positions >=max_distance map to the same bucket. All relative positions <=-max_distance map to the same bucket.
+        This should allow for more graceful generalization to longer sequences than the model has been trained on
+        """
+        relative_buckets = 0
+        if bidirectional:
+            num_buckets //= 2
+            relative_buckets += (relative_position > 0) * num_buckets
+            relative_position = jnp.abs(relative_position)
+        else:
+            relative_position = -jnp.clip(relative_position, a_max=0)
+        # now relative_position is in the range [0, inf)
+
+        # half of the buckets are for exact increments in positions
+        max_exact = num_buckets // 2
+        is_small = relative_position < max_exact
+
+        # The other half of the buckets are for logarithmically bigger bins in positions up to max_distance
+        relative_position_if_large = max_exact + (
+            jnp.log(relative_position / max_exact) / jnp.log(max_distance / max_exact) * (num_buckets - max_exact)
+        )
+        relative_position_if_large = jnp.clip(relative_position_if_large, a_max=num_buckets - 1)
+
+        relative_buckets += jnp.where(is_small, relative_position, relative_position_if_large)
+
+        return relative_buckets.astype("i4")
+
+    def compute_bias(self, query_length, key_length):
+        """Compute binned relative position bias"""
+        context_position = jnp.arange(query_length, dtype="i4")[:, None]
+        memory_position = jnp.arange(key_length, dtype="i4")[None, :]
+
+        relative_position = memory_position - context_position
+        relative_position_bucket = self._relative_position_bucket(
+            relative_position,
+            bidirectional=(not self.causal),
+            num_buckets=self.relative_attention_num_buckets,
+            max_distance=self.relative_attention_max_distance,
+        )
+
+        values = self.relative_attention_bias(relative_position_bucket)
+        values = values.transpose((2, 0, 1))[None, :, :, :]
+        return values
+
+    def _split_heads(self, hidden_states):
+        return hidden_states.reshape(hidden_states.shape[:2] + (self.n_heads, self.key_value_proj_dim))
+
+    def _merge_heads(self, hidden_states):
+        return hidden_states.reshape(hidden_states.shape[:2] + (self.inner_dim,))
+
+    @nn.compact
+    def _concatenate_to_cache(self, key, value, query, attention_mask):
+        """
+        This function takes projected key, value states from a single input token and concatenates the states to cached
+        states from previous steps. This function is slighly adapted from the official Flax repository:
+        https://github.com/google/flax/blob/491ce18759622506588784b4fca0e4bf05f8c8cd/flax/linen/attention.py#L252
+        """
+        # detect if we're initializing by absence of existing cache data.
+        is_initialized = self.has_variable("cache", "cached_key")
+        cached_key = self.variable("cache", "cached_key", jnp.zeros, key.shape, key.dtype)
+        cached_value = self.variable("cache", "cached_value", jnp.zeros, value.shape, value.dtype)
+        cache_index = self.variable("cache", "cache_index", lambda: jnp.array(0, dtype=jnp.int32))
+
+        if is_initialized:
+            *batch_dims, max_length, num_heads, depth_per_head = cached_key.value.shape
+            # update key, value caches with our new 1d spatial slices
+            cur_index = cache_index.value
+            indices = (0,) * len(batch_dims) + (cur_index, 0, 0)
+            key = jax.lax.dynamic_update_slice(cached_key.value, key, indices)
+            value = jax.lax.dynamic_update_slice(cached_value.value, value, indices)
+            cached_key.value = key
+            cached_value.value = value
+            num_updated_cache_vectors = query.shape[1]
+            cache_index.value = cache_index.value + num_updated_cache_vectors
+            # causal mask for cached decoder self-attention: our single query position should only attend to those key positions
+            # that have already been generated and cached, not the remaining zero elements.
+            pad_mask = jnp.broadcast_to(
+                jnp.arange(max_length) < cur_index + num_updated_cache_vectors,
+                tuple(batch_dims) + (1, num_updated_cache_vectors, max_length),
+            )
+            attention_mask = combine_masks(pad_mask, attention_mask)
+        return key, value, attention_mask
+
+    def _create_position_bias(
+        self, key_states, query_states, attention_mask, init_cache, seq_length, causal_attention_mask_shift
+    ):
+        cache_is_filled = self.causal and self.has_variable("cache", "cached_key") and (not init_cache)
+        key_length = key_states.shape[1]
+        query_length = key_length if cache_is_filled else query_states.shape[1]
+
+        if self.has_relative_attention_bias:
+            position_bias = self.compute_bias(query_length, key_length)
+        elif attention_mask is not None:
+            position_bias = jnp.zeros_like(attention_mask)
+        else:
+            position_bias = jnp.zeros((1, self.n_heads, query_length, key_length), dtype=self.dtype)
+
+        # if key and values are already calculated, only the last query position bias should be taken
+        if cache_is_filled:
+            max_decoder_length = self.variables["cache"]["cached_key"].shape[1]
+            position_bias = jax.lax.dynamic_slice(
+                position_bias,
+                (0, 0, causal_attention_mask_shift, 0),
+                (1, self.n_heads, seq_length, max_decoder_length),
+            )
+        return position_bias
+
+    def __call__(
+        self,
+        hidden_states,
+        attention_mask=None,
+        key_value_states=None,
+        position_bias=None,
+        use_cache=False,
+        output_attentions=False,
+        deterministic=True,
+        init_cache=False,
+    ):
+        """
+        Self-attention (if key_value_states is None) or attention over source sentence (provided by key_value_states).
+        """
+        batch_size, seq_length = hidden_states.shape[:2]
+
+        # q, k, v projections
+        query_states = self.q(hidden_states)  # (batch_size, n_heads, seq_length, dim_per_head)
+        key_states = self.k(hidden_states) if key_value_states is None else self.k(key_value_states)
+        value_states = self.v(hidden_states) if key_value_states is None else self.v(key_value_states)
+
+        # reshape to (batch_size, seq_length, n_heads, head_dim)
+        query_states = self._split_heads(query_states)
+        key_states = self._split_heads(key_states)
+        value_states = self._split_heads(value_states)
+
+        # counter-act scaling in dot_product_attention_weights function
+        query_states *= jnp.sqrt(query_states.shape[-1])
+
+        # for fast decoding causal attention mask should be shifted
+        causal_attention_mask_shift = (
+            self.variables["cache"]["cache_index"] if (self.has_variable("cache", "cached_key") and self.causal) else 0
+        )
+        # create causal attention_mask; attention_mask has to be defined when model is causal
+        if self.causal:
+            causal_attention_mask = make_causal_mask(attention_mask, dtype="bool")
+
+            # fast decoding for generate requires special attention_mask
+            if self.has_variable("cache", "cached_key"):
+                max_decoder_length = self.variables["cache"]["cached_key"].shape[1]
+                causal_attention_mask = jax.lax.dynamic_slice(
+                    causal_attention_mask,
+                    (0, 0, causal_attention_mask_shift, 0),
+                    (1, 1, seq_length, max_decoder_length),
+                )
+
+            # broadcast causal attention mask & attention mask to fit for merge
+            causal_attention_mask = jnp.broadcast_to(
+                causal_attention_mask, (batch_size,) + causal_attention_mask.shape[1:]
+            )
+            attention_mask = jnp.broadcast_to(
+                jnp.expand_dims(attention_mask, axis=(-3, -2)), causal_attention_mask.shape
+            )
+            attention_mask = combine_masks(attention_mask, causal_attention_mask)
+        elif attention_mask is not None:
+            attention_mask = jnp.expand_dims(attention_mask, axis=(-3, -2))
+
+        # During fast autoregressive decoding, we feed one position at a time,
+        # and cache the keys and values step by step.
+        if self.causal and (self.has_variable("cache", "cached_key") or init_cache):
+            key_states, value_states, attention_mask = self._concatenate_to_cache(
+                key_states, value_states, query_states, attention_mask
+            )
+
+        # replace masked positions with -10_000
+        if attention_mask is not None:
+            mask_value = jnp.finfo(self.dtype).min
+            attention_mask = jax.lax.select(
+                attention_mask > 0,
+                jnp.full(attention_mask.shape, 0.0).astype(self.dtype),
+                jnp.full(attention_mask.shape, mask_value).astype(self.dtype),
+            )
+
+        if position_bias is None:
+            # compute position bias (only for first layer)
+            position_bias = self._create_position_bias(
+                key_states, query_states, attention_mask, init_cache, seq_length, causal_attention_mask_shift
+            )
+
+            if attention_mask is not None:
+                position_bias = position_bias + attention_mask
+
+        # create dropout rng
+        dropout_rng = None
+        if not deterministic and self.dropout > 0.0:
+            dropout_rng = self.make_rng("dropout")
+
+        # Softmax(QK^T)
+        attn_weights = dot_product_attention_weights(
+            query_states,
+            key_states,
+            bias=position_bias,
+            dropout_rng=dropout_rng,
+            dropout_rate=self.dropout,
+            broadcast_dropout=True,
+            deterministic=deterministic,
+            dtype=self.dtype,
+        )
+
+        # multiply with value states
+        attn_output = jnp.einsum("...hqk,...khd->...qhd", attn_weights, value_states)
+
+        # bring back to (batch_size, seq_length, d_model)
+        attn_output = self._merge_heads(attn_output)
+
+        # apply output matrix
+        attn_output = self.o(attn_output)
+
+        outputs = (attn_output, position_bias)
+
+        if output_attentions:
+            outputs = outputs + (attn_weights,)
+
+        return outputs
+
+
+class FlaxLongT5LocalAttention(nn.Module):
+    config: LongT5Config
+    has_relative_attention_bias: bool = False
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        self.relative_attention_num_buckets = self.config.relative_attention_num_buckets
+        self.relative_attention_max_distance = self.config.relative_attention_max_distance
+        self.d_model = self.config.d_model
+        self.key_value_proj_dim = self.config.d_kv
+        self.n_heads = self.config.num_heads
+        self.local_radius = self.config.local_radius
+        self.block_len = self.local_radius + 1
+        self.dropout = self.config.dropout_rate
+        self.inner_dim = self.n_heads * self.key_value_proj_dim
+
+        q_init_std = self.config.initializer_factor * ((self.inner_dim * self.key_value_proj_dim) ** -0.5)
+        kv_init_std = self.config.initializer_factor * (self.inner_dim**-0.5)
+        o_init_std = self.config.initializer_factor * (self.inner_dim**-0.5)
+
+        self.q = nn.Dense(
+            self.inner_dim,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(q_init_std),
+            dtype=self.dtype,
+        )
+        self.k = nn.Dense(
+            self.inner_dim,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(kv_init_std),
+            dtype=self.dtype,
+        )
+        self.v = nn.Dense(
+            self.inner_dim,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(kv_init_std),
+            dtype=self.dtype,
+        )
+        self.o = nn.Dense(
+            self.d_model,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(o_init_std),
+            dtype=self.dtype,
+        )
+
+        if self.has_relative_attention_bias:
+            self.relative_attention_bias = nn.Embed(
+                self.relative_attention_num_buckets,
+                self.n_heads,
+                embedding_init=jax.nn.initializers.normal(kv_init_std),
+            )
+
+    @staticmethod
+    # Copied from transformers.models.t5.modeling_flax_t5.FlaxT5Attention._relative_position_bucket
+    def _relative_position_bucket(relative_position, bidirectional=True, num_buckets=32, max_distance=128):
+        """
+        Adapted from Mesh Tensorflow:
+        https://github.com/tensorflow/mesh/blob/0cb87fe07da627bf0b7e60475d59f95ed6b5be3d/mesh_tensorflow/transformer/transformer_layers.py#L593
+
+        Translate relative position to a bucket number for relative attention. The relative position is defined as
+        memory_position - query_position, i.e. the distance in tokens from the attending position to the attended-to
+        position. If bidirectional=False, then positive relative positions are invalid. We use smaller buckets for
+        small absolute relative_position and larger buckets for larger absolute relative_positions. All relative
+        positions >=max_distance map to the same bucket. All relative positions <=-max_distance map to the same bucket.
+        This should allow for more graceful generalization to longer sequences than the model has been trained on
+        """
+        relative_buckets = 0
+        if bidirectional:
+            num_buckets //= 2
+            relative_buckets += (relative_position > 0) * num_buckets
+            relative_position = jnp.abs(relative_position)
+        else:
+            relative_position = -jnp.clip(relative_position, a_max=0)
+        # now relative_position is in the range [0, inf)
+
+        # half of the buckets are for exact increments in positions
+        max_exact = num_buckets // 2
+        is_small = relative_position < max_exact
+
+        # The other half of the buckets are for logarithmically bigger bins in positions up to max_distance
+        relative_position_if_large = max_exact + (
+            jnp.log(relative_position / max_exact) / jnp.log(max_distance / max_exact) * (num_buckets - max_exact)
+        )
+        relative_position_if_large = jnp.clip(relative_position_if_large, a_max=num_buckets - 1)
+
+        relative_buckets += jnp.where(is_small, relative_position, relative_position_if_large)
+
+        return relative_buckets.astype("i4")
+
+    def compute_bias(self, block_length: int):
+        """Compute binned relative position bias"""
+        memory_position = jnp.arange(3 * block_length, dtype="i4")
+        context_position = memory_position[block_length:-block_length]
+
+        relative_position = memory_position[None, :] - context_position[:, None]
+        relative_position_bucket = self._relative_position_bucket(
+            relative_position,
+            bidirectional=True,
+            num_buckets=self.relative_attention_num_buckets,
+            max_distance=self.relative_attention_max_distance,
+        )
+
+        values = self.relative_attention_bias(relative_position_bucket)
+        values = values.transpose((2, 0, 1))[None, None, :, :, :]
+        return values
+
+    def _split_heads(self, hidden_states):
+        return hidden_states.reshape(hidden_states.shape[:2] + (self.n_heads, self.key_value_proj_dim))
+
+    def _merge_heads(self, hidden_states):
+        return hidden_states.reshape(hidden_states.shape[0], -1, self.inner_dim)
+
+    def _create_position_bias(self, block_len: int, attention_mask: Optional[np.ndarray]) -> np.ndarray:
+        # position_bias shape: # (1, 1, n_heads, block_len, 3 * block_len)
+        if self.has_relative_attention_bias:
+            position_bias = self.compute_bias(block_len)
+        elif attention_mask is not None:
+            position_bias = jnp.zeros_like(attention_mask)
+        else:
+            position_bias = jnp.zeros((1, 1, self.n_heads, block_len, 3 * block_len), dtype=self.dtype)
+
+        return position_bias
+
+    def __call__(
+        self,
+        hidden_states,
+        attention_mask=None,
+        key_value_states=None,
+        position_bias=None,
+        output_attentions=False,
+        deterministic=True,
+    ):
+        """
+        Self-attention (if key_value_states is None) or attention over source sentence (provided by key_value_states).
+        """
+        batch_size, seq_length = hidden_states.shape[:2]
+
+        # q, k, v projections
+        query_states = self.q(hidden_states)  # (batch_size, n_heads, seq_length, dim_per_head)
+        key_states = self.k(hidden_states) if key_value_states is None else self.k(key_value_states)
+        value_states = self.v(hidden_states) if key_value_states is None else self.v(key_value_states)
+
+        # reshape to (batch_size, seq_length, n_heads, head_dim)
+        query_states = self._split_heads(query_states)
+        key_states = self._split_heads(key_states)
+        value_states = self._split_heads(value_states)
+
+        # Split into blocks -> (batch_size, num_blocks, block_len, n_heads, head_dim)
+        query_states = _split_into_blocks(query_states, self.block_len, axis=1)
+        key_states = _split_into_blocks(key_states, self.block_len, axis=1)
+        value_states = _split_into_blocks(value_states, self.block_len, axis=1)
+
+        # Concatenate 3 blocks for keys and values -> (batch_size, num_blocks, 3 * block_len, n_heads, dim_per_head)
+        key_states = _concatenate_3_blocks(key_states, block_axis=1, sequence_axis=2)
+        value_states = _concatenate_3_blocks(value_states, block_axis=1, sequence_axis=2)
+
+        # counter-act scaling in dot_product_attention_weights function
+        query_states *= jnp.sqrt(query_states.shape[-1])
+
+        if attention_mask is not None:
+            attention_mask = _get_local_attention_mask(attention_mask, self.block_len)
+
+            # replace masked positions with -10_000
+            attention_mask = jax.lax.select(
+                attention_mask > 0,
+                jnp.full(attention_mask.shape, 0.0).astype(self.dtype),
+                jnp.full(attention_mask.shape, -1e10).astype(self.dtype),
+            )
+
+        if position_bias is None:
+            # compute position bias (only for first layer)
+            position_bias = self._create_position_bias(self.block_len, attention_mask)
+
+            if attention_mask is not None:
+                position_bias = position_bias + attention_mask.swapaxes(1, 2)
+
+        # create dropout rng
+        dropout_rng = None
+        if not deterministic and self.dropout > 0.0:
+            dropout_rng = self.make_rng("dropout")
+
+        # Softmax(QK^T)
+        attn_weights = dot_product_attention_weights(
+            query_states,
+            key_states,
+            bias=position_bias,
+            dropout_rng=dropout_rng,
+            dropout_rate=self.dropout,
+            broadcast_dropout=True,
+            deterministic=deterministic,
+            dtype=self.dtype,
+        )
+
+        # multiply with value states
+        attn_output = jnp.einsum("...hqk,...khd->...qhd", attn_weights, value_states)
+
+        # bring back to (batch_size, seq_length, d_model)
+        attn_output = self._merge_heads(attn_output)
+        attn_output = attn_output[:, :seq_length, :]
+
+        # apply output matrix
+        attn_output = self.o(attn_output)
+
+        outputs = (attn_output, position_bias)
+
+        if output_attentions:
+            outputs = outputs + (attn_weights,)
+
+        return outputs
+
+
+class FlaxLongT5TransientGlobalAttention(nn.Module):
+    config: LongT5Config
+    has_relative_attention_bias: bool = False
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        self.relative_attention_num_buckets = self.config.relative_attention_num_buckets
+        self.relative_attention_max_distance = self.config.relative_attention_max_distance
+        self.d_model = self.config.d_model
+        self.key_value_proj_dim = self.config.d_kv
+        self.n_heads = self.config.num_heads
+        self.local_radius = self.config.local_radius
+        self.block_len = self.local_radius + 1
+        self.global_block_size = self.config.global_block_size
+        self.dropout = self.config.dropout_rate
+        self.inner_dim = self.n_heads * self.key_value_proj_dim
+
+        q_init_std = self.config.initializer_factor * ((self.inner_dim * self.key_value_proj_dim) ** -0.5)
+        kv_init_std = self.config.initializer_factor * (self.inner_dim**-0.5)
+        o_init_std = self.config.initializer_factor * (self.inner_dim**-0.5)
+
+        self.q = nn.Dense(
+            self.inner_dim,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(q_init_std),
+            dtype=self.dtype,
+        )
+        self.k = nn.Dense(
+            self.inner_dim,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(kv_init_std),
+            dtype=self.dtype,
+        )
+        self.v = nn.Dense(
+            self.inner_dim,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(kv_init_std),
+            dtype=self.dtype,
+        )
+        self.o = nn.Dense(
+            self.d_model,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(o_init_std),
+            dtype=self.dtype,
+        )
+
+        if self.has_relative_attention_bias:
+            self.relative_attention_bias = nn.Embed(
+                self.relative_attention_num_buckets,
+                self.n_heads,
+                embedding_init=jax.nn.initializers.normal(kv_init_std),
+            )
+
+        # Relativen attention bias & Layer norm for global attention
+        if self.has_relative_attention_bias:
+            self.global_relative_attention_bias = nn.Embed(
+                self.relative_attention_num_buckets,
+                self.n_heads,
+                embedding_init=jax.nn.initializers.normal(kv_init_std),
+            )
+        self.global_input_layer_norm = FlaxLongT5LayerNorm(
+            self.config.d_model, eps=self.config.layer_norm_epsilon, dtype=self.dtype
+        )
+
+    @staticmethod
+    # Copied from transformers.models.t5.modeling_flax_t5.FlaxT5Attention._relative_position_bucket
+    def _relative_position_bucket(relative_position, bidirectional=True, num_buckets=32, max_distance=128):
+        """
+        Adapted from Mesh Tensorflow:
+        https://github.com/tensorflow/mesh/blob/0cb87fe07da627bf0b7e60475d59f95ed6b5be3d/mesh_tensorflow/transformer/transformer_layers.py#L593
+
+        Translate relative position to a bucket number for relative attention. The relative position is defined as
+        memory_position - query_position, i.e. the distance in tokens from the attending position to the attended-to
+        position. If bidirectional=False, then positive relative positions are invalid. We use smaller buckets for
+        small absolute relative_position and larger buckets for larger absolute relative_positions. All relative
+        positions >=max_distance map to the same bucket. All relative positions <=-max_distance map to the same bucket.
+        This should allow for more graceful generalization to longer sequences than the model has been trained on
+        """
+        relative_buckets = 0
+        if bidirectional:
+            num_buckets //= 2
+            relative_buckets += (relative_position > 0) * num_buckets
+            relative_position = jnp.abs(relative_position)
+        else:
+            relative_position = -jnp.clip(relative_position, a_max=0)
+        # now relative_position is in the range [0, inf)
+
+        # half of the buckets are for exact increments in positions
+        max_exact = num_buckets // 2
+        is_small = relative_position < max_exact
+
+        # The other half of the buckets are for logarithmically bigger bins in positions up to max_distance
+        relative_position_if_large = max_exact + (
+            jnp.log(relative_position / max_exact) / jnp.log(max_distance / max_exact) * (num_buckets - max_exact)
+        )
+        relative_position_if_large = jnp.clip(relative_position_if_large, a_max=num_buckets - 1)
+
+        relative_buckets += jnp.where(is_small, relative_position, relative_position_if_large)
+
+        return relative_buckets.astype("i4")
+
+    def compute_bias(self, block_length: int):
+        """Compute binned relative position bias"""
+        memory_position = jnp.arange(3 * block_length, dtype="i4")
+        context_position = memory_position[block_length:-block_length]
+
+        relative_position = memory_position[None, :] - context_position[:, None]
+        relative_position_bucket = self._relative_position_bucket(
+            relative_position,
+            bidirectional=True,
+            num_buckets=self.relative_attention_num_buckets,
+            max_distance=self.relative_attention_max_distance,
+        )
+
+        values = self.relative_attention_bias(relative_position_bucket)
+        values = values.transpose((2, 0, 1))[None, None, :, :, :]
+        return values
+
+    def compute_side_bias(self, attention_mask: np.ndarray, global_segment_ids: np.ndarray) -> np.ndarray:
+        # (batch_size, 1, 1, seq_len, global_seq_len)
+        side_attention_mask = jnp.equal(attention_mask[..., None], global_segment_ids[:, None, :])[:, None, ...]
+        attention_side_bias = jax.lax.select(
+            side_attention_mask > 0,
+            jnp.full(side_attention_mask.shape, 0.0).astype(self.dtype),
+            jnp.full(side_attention_mask.shape, -1e10).astype(self.dtype),
+        )
+        # (batch_size, seq_len, global_seq_len)
+        side_relative_position = _make_side_relative_position_ids(attention_mask, self.global_block_size)
+        side_relative_position_bucket = self._relative_position_bucket(
+            side_relative_position,
+            bidirectional=True,
+            num_buckets=self.relative_attention_num_buckets,
+            max_distance=self.relative_attention_max_distance,
+        )
+        # (batch_size, seq_len, global_seq_len, num_heads)
+        side_bias = self.global_relative_attention_bias(side_relative_position_bucket)
+
+        # (batch_size, 1, num_heads, seq_len, global_seq_len)
+        side_bias = jnp.transpose(side_bias, (0, 3, 1, 2))
+        # (batch_size, num_heads, seq_len, global_seq_len)
+        attention_side_bias = attention_side_bias + side_bias
+        return attention_side_bias
+
+    def _split_heads(self, hidden_states):
+        return hidden_states.reshape(hidden_states.shape[:2] + (self.n_heads, self.key_value_proj_dim))
+
+    def _merge_heads(self, hidden_states):
+        return hidden_states.reshape(hidden_states.shape[0], -1, self.inner_dim)
+
+    def _create_position_bias(self, block_len: int, attention_mask: Optional[np.ndarray]) -> np.ndarray:
+        # position_bias shape: # (1, 1, n_heads, block_len, 3 * block_len)
+        if self.has_relative_attention_bias:
+            position_bias = self.compute_bias(block_len)
+        elif attention_mask is not None:
+            position_bias = jnp.zeros_like(attention_mask)
+        else:
+            position_bias = jnp.zeros((1, 1, self.n_heads, block_len, 3 * block_len), dtype=self.dtype)
+
+        return position_bias
+
+    def __call__(
+        self,
+        hidden_states,
+        attention_mask=None,
+        key_value_states=None,
+        position_bias=None,
+        output_attentions=False,
+        deterministic=True,
+    ):
+        """
+        Self-attention (if key_value_states is None) or attention over source sentence (provided by key_value_states).
+        """
+        batch_size, seq_length = hidden_states.shape[:2]
+
+        # Prepare components for transient-global attention
+        # Obtain block_ids and global_segment_ids
+        # global_seq_len := seq_len // self.global_block_size
+        # shapes: (batch_size, seq_len) & (batch_size, global_seq_len)
+        block_ids, global_segment_ids = _make_global_fixed_block_ids(
+            attention_mask if attention_mask is not None else jnp.ones((batch_size, seq_length)),
+            self.global_block_size,
+        )
+        # Create global inputs
+        _global_seq_len = global_segment_ids.shape[-1]
+        global_inputs = _create_global_aggregates(hidden_states, block_ids, _global_seq_len)
+        global_inputs = self.global_input_layer_norm(global_inputs)
+
+        # q, k, v projections
+        query_states = self.q(hidden_states)  # (batch_size, n_heads, seq_length, dim_per_head)
+        key_states = self.k(hidden_states) if key_value_states is None else self.k(key_value_states)
+        value_states = self.v(hidden_states) if key_value_states is None else self.v(key_value_states)
+
+        # reshape to (batch_size, seq_length, n_heads, head_dim)
+        query_states = self._split_heads(query_states)
+        key_states = self._split_heads(key_states)
+        value_states = self._split_heads(value_states)
+
+        # Get global/side key/value_states
+        side_key_states = self.k(global_inputs)
+        side_value_states = self.v(global_inputs)
+
+        # reshape to (batch_size, global_seq_len, n_heads, head_dim)
+        side_key_states = self._split_heads(side_key_states)
+        side_value_states = self._split_heads(side_value_states)
+
+        # Split into blocks -> (batch_size, num_blocks, block_len, n_heads, head_dim)
+        query_states = _split_into_blocks(query_states, self.block_len, axis=1)
+        key_states = _split_into_blocks(key_states, self.block_len, axis=1)
+        value_states = _split_into_blocks(value_states, self.block_len, axis=1)
+
+        # Concatenate 3 blocks for keys and values -> (batch_size, num_blocks, 3 * block_len, n_heads, dim_per_head)
+        key_states = _concatenate_3_blocks(key_states, block_axis=1, sequence_axis=2)
+        value_states = _concatenate_3_blocks(value_states, block_axis=1, sequence_axis=2)
+
+        # Tile side inputs across local key/value blocks
+        # New shape: (batch_size, num_blocks, global_seq_len, n_heads, dim_per_head)
+        reps = [1] * (side_key_states.ndim + 1)
+        reps[1] = key_states.shape[1]
+        side_key_states = jnp.tile(side_key_states[:, None, ...], reps)
+        side_value_states = jnp.tile(side_value_states[:, None, ...], reps)
+
+        # Concatenate "local" and "side"/"global" key/value states to allow each token to attend global aggregated ones
+        # New shape: (batch_size, num_blocks, 3 * block_len + global_seq_len, n_heads, dim_per_head)
+        key_states = jnp.concatenate((key_states, side_key_states), axis=2)
+        value_states = jnp.concatenate((value_states, side_value_states), axis=2)
+
+        # counter-act scaling in dot_product_attention_weights function
+        query_states *= jnp.sqrt(query_states.shape[-1])
+
+        if attention_mask is not None:
+            local_attention_mask = _get_local_attention_mask(attention_mask, self.block_len)
+            local_attention_mask = jax.lax.select(
+                local_attention_mask > 0,
+                jnp.full(local_attention_mask.shape, 0.0).astype(self.dtype),
+                jnp.full(local_attention_mask.shape, -1e10).astype(self.dtype),
+            )
+        else:
+            local_attention_mask = None
+
+        if position_bias is None:
+            # compute position bias (only for first layer)
+            position_bias = self._create_position_bias(self.block_len, attention_mask)
+            if local_attention_mask is not None:
+                position_bias = position_bias + local_attention_mask.swapaxes(1, 2)
+
+            # Calculate global/side bias - shape: # (batch_size, num_heads, seq_len, global_seq_len)
+            if attention_mask is None:
+                attention_mask = jnp.ones((batch_size, seq_length))
+            side_position_bias = self.compute_side_bias(attention_mask, global_segment_ids)
+            side_position_bias = _split_into_blocks(side_position_bias, self.block_len, axis=-2)
+            side_position_bias = jnp.swapaxes(side_position_bias, 1, 2)
+            position_bias = jnp.concatenate((position_bias, side_position_bias), axis=-1)
+
+        # create dropout rng
+        dropout_rng = None
+        if not deterministic and self.dropout > 0.0:
+            dropout_rng = self.make_rng("dropout")
+
+        # Softmax(QK^T)
+        attn_weights = dot_product_attention_weights(
+            query_states,
+            key_states,
+            bias=position_bias,
+            dropout_rng=dropout_rng,
+            dropout_rate=self.dropout,
+            broadcast_dropout=True,
+            deterministic=deterministic,
+            dtype=self.dtype,
+        )
+
+        # multiply with value states
+        attn_output = jnp.einsum("...hqk,...khd->...qhd", attn_weights, value_states)
+
+        # bring back to (batch_size, seq_length, d_model)
+        attn_output = self._merge_heads(attn_output)
+        attn_output = attn_output[:, :seq_length, :]
+
+        # apply output matrix
+        attn_output = self.o(attn_output)
+
+        outputs = (attn_output, position_bias)
+
+        if output_attentions:
+            outputs = outputs + (attn_weights,)
+
+        return outputs
+
+
+class FlaxLongT5LayerLocalSelfAttention(nn.Module):
+    """Local self attention used in encoder"""
+
+    config: LongT5Config
+    has_relative_attention_bias: bool = False
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        self.LocalSelfAttention = FlaxLongT5LocalAttention(
+            self.config, has_relative_attention_bias=self.has_relative_attention_bias, dtype=self.dtype
+        )
+        self.layer_norm = FlaxLongT5LayerNorm(
+            self.config.d_model, eps=self.config.layer_norm_epsilon, dtype=self.dtype
+        )
+        self.dropout = nn.Dropout(self.config.dropout_rate)
+
+    def __call__(
+        self,
+        hidden_states,
+        attention_mask=None,
+        position_bias=None,
+        output_attentions=False,
+        deterministic=True,
+        **kwargs: Any,  # to accept init_cache kwargs
+    ):
+        normed_hidden_states = self.layer_norm(hidden_states)
+        attention_output = self.LocalSelfAttention(
+            normed_hidden_states,
+            attention_mask=attention_mask,
+            position_bias=position_bias,
+            output_attentions=output_attentions,
+            deterministic=deterministic,
+        )
+        hidden_states = hidden_states + self.dropout(attention_output[0], deterministic=deterministic)
+        outputs = (hidden_states,) + attention_output[1:]  # add attentions if we output them
+        return outputs
+
+
+class FlaxLongT5LayerTransientGlobalSelfAttention(nn.Module):
+    """Transient-Global self attention used in encoder"""
+
+    config: LongT5Config
+    has_relative_attention_bias: bool = False
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        self.TransientGlobalSelfAttention = FlaxLongT5TransientGlobalAttention(
+            self.config, has_relative_attention_bias=self.has_relative_attention_bias, dtype=self.dtype
+        )
+        self.layer_norm = FlaxLongT5LayerNorm(
+            self.config.d_model, eps=self.config.layer_norm_epsilon, dtype=self.dtype
+        )
+        self.dropout = nn.Dropout(self.config.dropout_rate)
+
+    def __call__(
+        self,
+        hidden_states,
+        attention_mask=None,
+        position_bias=None,
+        output_attentions=False,
+        deterministic=True,
+        **kwargs: Any,  # to accept init_cache kwargs
+    ):
+        normed_hidden_states = self.layer_norm(hidden_states)
+        attention_output = self.TransientGlobalSelfAttention(
+            normed_hidden_states,
+            attention_mask=attention_mask,
+            position_bias=position_bias,
+            output_attentions=output_attentions,
+            deterministic=deterministic,
+        )
+        hidden_states = hidden_states + self.dropout(attention_output[0], deterministic=deterministic)
+        outputs = (hidden_states,) + attention_output[1:]  # add attentions if we output them
+        return outputs
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5LayerSelfAttention with T5->LongT5
+class FlaxLongT5LayerSelfAttention(nn.Module):
+    config: LongT5Config
+    has_relative_attention_bias: bool = False
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        self.SelfAttention = FlaxLongT5Attention(
+            self.config,
+            has_relative_attention_bias=self.has_relative_attention_bias,
+            causal=self.config.causal,
+            dtype=self.dtype,
+        )
+        self.layer_norm = FlaxLongT5LayerNorm(
+            self.config.d_model, eps=self.config.layer_norm_epsilon, dtype=self.dtype
+        )
+        self.dropout = nn.Dropout(self.config.dropout_rate)
+
+    def __call__(
+        self,
+        hidden_states,
+        attention_mask=None,
+        position_bias=None,
+        output_attentions=False,
+        deterministic=True,
+        init_cache=False,
+    ):
+        normed_hidden_states = self.layer_norm(hidden_states)
+        attention_output = self.SelfAttention(
+            normed_hidden_states,
+            attention_mask=attention_mask,
+            position_bias=position_bias,
+            output_attentions=output_attentions,
+            deterministic=deterministic,
+            init_cache=init_cache,
+        )
+        hidden_states = hidden_states + self.dropout(attention_output[0], deterministic=deterministic)
+        outputs = (hidden_states,) + attention_output[1:]  # add attentions if we output them
+        return outputs
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5LayerCrossAttention with T5->LongT5
+class FlaxLongT5LayerCrossAttention(nn.Module):
+    config: LongT5Config
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        self.EncDecAttention = FlaxLongT5Attention(
+            self.config, has_relative_attention_bias=False, causal=False, dtype=self.dtype
+        )
+        self.layer_norm = FlaxLongT5LayerNorm(
+            self.config.d_model, eps=self.config.layer_norm_epsilon, dtype=self.dtype
+        )
+        self.dropout = nn.Dropout(self.config.dropout_rate)
+
+    def __call__(
+        self,
+        hidden_states,
+        key_value_states,
+        attention_mask=None,
+        position_bias=None,
+        output_attentions=False,
+        deterministic=True,
+    ):
+        normed_hidden_states = self.layer_norm(hidden_states)
+        attention_output = self.EncDecAttention(
+            normed_hidden_states,
+            attention_mask=attention_mask,
+            key_value_states=key_value_states,
+            position_bias=position_bias,
+            output_attentions=output_attentions,
+        )
+        hidden_states = hidden_states + self.dropout(attention_output[0], deterministic=deterministic)
+        outputs = (hidden_states,) + attention_output[1:]  # add attentions if we output them
+        return outputs
+
+
+class FlaxLongT5Block(nn.Module):
+    config: LongT5Config
+    has_relative_attention_bias: bool = False
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        self.causal = self.config.causal
+        if self.causal:
+            attention_layer = FlaxLongT5LayerSelfAttention
+        elif self.config.encoder_attention_type == "local":
+            attention_layer = FlaxLongT5LayerLocalSelfAttention
+        elif self.config.encoder_attention_type == "transient-global":
+            attention_layer = FlaxLongT5LayerTransientGlobalSelfAttention
+        else:
+            raise ValueError(
+                "For encoder attention mechanism, either `local` or `transient-global` attention type is expected, "
+                f"but got {self.config.encoder_attention_type}."
+            )
+        self.layer = (
+            attention_layer(
+                self.config,
+                has_relative_attention_bias=self.has_relative_attention_bias,
+                name=str(0),
+                dtype=self.dtype,
+            ),
+        )
+        feed_forward_index = 1
+        if self.causal:
+            self.layer += (FlaxLongT5LayerCrossAttention(self.config, name=str(1), dtype=self.dtype),)
+            feed_forward_index += 1
+
+        self.layer += (FlaxLongT5LayerFF(self.config, name=str(feed_forward_index), dtype=self.dtype),)
+
+    # Copied from transformers.models.t5.modeling_flax_t5.FlaxT5Block.__call__ with T5->LongT5
+    def __call__(
+        self,
+        hidden_states,
+        attention_mask=None,
+        position_bias=None,
+        encoder_hidden_states=None,
+        encoder_attention_mask=None,
+        encoder_decoder_position_bias=None,
+        output_attentions=False,
+        return_dict=True,
+        deterministic=True,
+        init_cache=False,
+    ):
+        self_attention_outputs = self.layer[0](
+            hidden_states,
+            attention_mask=attention_mask,
+            position_bias=position_bias,
+            output_attentions=output_attentions,
+            deterministic=deterministic,
+            init_cache=init_cache,
+        )
+        hidden_states = self_attention_outputs[0]
+        attention_outputs = self_attention_outputs[1:]  # Keep self-attention outputs and relative position weights
+
+        do_cross_attention = self.causal and encoder_hidden_states is not None
+        if do_cross_attention:
+            cross_attention_outputs = self.layer[1](
+                hidden_states,
+                key_value_states=encoder_hidden_states,
+                attention_mask=encoder_attention_mask,
+                position_bias=encoder_decoder_position_bias,
+                output_attentions=output_attentions,
+                deterministic=deterministic,
+            )
+            hidden_states = cross_attention_outputs[0]
+
+            # Keep cross-attention outputs and relative position weights
+            attention_outputs = attention_outputs + cross_attention_outputs[1:]
+
+        # Apply Feed Forward layer
+        hidden_states = self.layer[-1](hidden_states, deterministic=deterministic)
+
+        outputs = (hidden_states,)
+
+        outputs = outputs + attention_outputs
+
+        # returns hidden-states, present_key_value_states, (self-attention position bias), (self-attention weights),
+        # (cross-attention position bias), (cross-attention weights)
+        return outputs
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5LayerCollection with T5->LongT5
+class FlaxLongT5LayerCollection(nn.Module):
+    config: LongT5Config
+    has_relative_attention_bias: bool
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+
+    def setup(self):
+        self.layer = FlaxLongT5Block(
+            self.config, has_relative_attention_bias=self.has_relative_attention_bias, dtype=self.dtype
+        )
+
+    def __call__(
+        self,
+        hidden_states,
+        attention_mask=None,
+        position_bias=None,
+        encoder_hidden_states=None,
+        encoder_attention_mask=None,
+        encoder_decoder_position_bias=None,
+        output_attentions=False,
+        deterministic=True,
+        init_cache=False,
+    ):
+        return self.layer(
+            hidden_states,
+            attention_mask=attention_mask,
+            position_bias=position_bias,
+            encoder_hidden_states=encoder_hidden_states,
+            encoder_attention_mask=encoder_attention_mask,
+            encoder_decoder_position_bias=encoder_decoder_position_bias,
+            output_attentions=output_attentions,
+            deterministic=deterministic,
+            init_cache=init_cache,
+        )
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5BlockCollection with T5->LongT5
+class FlaxLongT5BlockCollection(nn.Module):
+    config: LongT5Config
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+    gradient_checkpointing: bool = False
+
+    def setup(self):
+        self.causal = self.config.causal
+        if self.gradient_checkpointing:
+            FlaxLongT5CheckpointLayer = remat(FlaxLongT5LayerCollection, static_argnums=(6, 7, 8))
+            self.blocks = [
+                FlaxLongT5CheckpointLayer(
+                    self.config,
+                    has_relative_attention_bias=(i == 0),
+                    dtype=self.dtype,
+                    name=str(i),
+                )
+                for i in range(self.config.num_layers)
+            ]
+        else:
+            self.blocks = [
+                FlaxLongT5LayerCollection(
+                    self.config,
+                    has_relative_attention_bias=(i == 0),
+                    dtype=self.dtype,
+                    name=str(i),
+                )
+                for i in range(self.config.num_layers)
+            ]
+
+    def __call__(
+        self,
+        hidden_states=None,
+        attention_mask=None,
+        encoder_hidden_states=None,
+        encoder_attention_mask=None,
+        output_attentions: bool = False,
+        output_hidden_states: bool = False,
+        deterministic: bool = True,
+        init_cache: bool = False,
+    ):
+        # Prepare head mask if needed
+        all_hidden_states = () if output_hidden_states else None
+        all_attentions = () if output_attentions else None
+        all_cross_attentions = () if (output_attentions and self.causal) else None
+        position_bias = None
+        encoder_decoder_position_bias = None
+
+        for i, layer_module in enumerate(self.blocks):
+            if output_hidden_states:
+                all_hidden_states = all_hidden_states + (hidden_states,)
+
+            layer_outputs = layer_module(
+                hidden_states,
+                attention_mask,
+                position_bias,
+                encoder_hidden_states,
+                encoder_attention_mask,
+                encoder_decoder_position_bias,
+                output_attentions,
+                deterministic,
+                init_cache,
+            )
+
+            hidden_states = layer_outputs[0]
+
+            # We share the position biases between the layers - the first layer store them
+            # layer_outputs = hidden-states, key-value-states (self-attention position bias), (self-attention weights),
+            # (cross-attention position bias), (cross-attention weights)
+            position_bias = layer_outputs[1]
+
+            if self.causal and encoder_hidden_states is not None:
+                encoder_decoder_position_bias = layer_outputs[3 if output_attentions else 2]
+
+            if output_attentions:
+                all_attentions = all_attentions + (layer_outputs[2],)
+                if self.causal:
+                    all_cross_attentions = all_cross_attentions + (layer_outputs[4],)
+
+        return FlaxBaseModelOutputWithPastAndCrossAttentions(
+            last_hidden_state=hidden_states,
+            hidden_states=all_hidden_states,
+            attentions=all_attentions,
+            cross_attentions=all_cross_attentions,
+        )
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5Stack with T5->LongT5
+class FlaxLongT5Stack(nn.Module):
+    config: LongT5Config
+    embed_tokens: nn.Embed
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+    gradient_checkpointing: bool = False
+
+    def setup(self):
+        self.causal = self.config.causal
+
+        self.block = FlaxLongT5BlockCollection(
+            self.config, dtype=self.dtype, gradient_checkpointing=self.gradient_checkpointing
+        )
+        self.final_layer_norm = FlaxLongT5LayerNorm(
+            self.config.d_model, eps=self.config.layer_norm_epsilon, dtype=self.dtype
+        )
+        self.dropout = nn.Dropout(self.config.dropout_rate)
+
+    def __call__(
+        self,
+        input_ids=None,
+        attention_mask=None,
+        encoder_hidden_states=None,
+        encoder_attention_mask=None,
+        output_attentions: bool = False,
+        output_hidden_states: bool = False,
+        return_dict: bool = True,
+        deterministic: bool = True,
+        init_cache: bool = False,
+    ):
+        hidden_states = self.embed_tokens(input_ids)
+        hidden_states = self.dropout(hidden_states, deterministic=deterministic)
+
+        outputs = self.block(
+            hidden_states,
+            attention_mask=attention_mask,
+            encoder_hidden_states=encoder_hidden_states,
+            encoder_attention_mask=encoder_attention_mask,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            deterministic=deterministic,
+            init_cache=init_cache,
+        )
+
+        hidden_states = outputs[0]
+
+        hidden_states = self.final_layer_norm(hidden_states)
+        hidden_states = self.dropout(hidden_states, deterministic=deterministic)
+
+        # Add last layer
+        all_hidden_states = None
+
+        if output_hidden_states:
+            all_hidden_states = outputs.hidden_states
+            all_hidden_states = all_hidden_states + (hidden_states,)
+
+        if not return_dict:
+            if output_hidden_states:
+                return (
+                    hidden_states,
+                    all_hidden_states,
+                ) + outputs[2:]
+            return (hidden_states,) + outputs[1:]
+
+        return FlaxBaseModelOutputWithPastAndCrossAttentions(
+            last_hidden_state=hidden_states,
+            hidden_states=all_hidden_states,
+            attentions=outputs.attentions,
+            cross_attentions=outputs.cross_attentions,
+        )
+
+
+LONGT5_ENCODE_INPUTS_DOCSTRING = r"""
+    Args:
+        input_ids (`jnp.ndarray` of shape `(batch_size, sequence_length)`):
+            Indices of input sequence tokens in the vocabulary. LongT5 is a model with relative position embeddings so
+            you should be able to pad the inputs on both the right and the left.
+
+            Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
+            [`PreTrainedTokenizer.__call__`] for detail.
+
+            To know more on how to prepare `input_ids` for pretraining take a look a [LONGT5
+            Training](./longt5#training).
+        attention_mask (`jnp.ndarray` of shape `(batch_size, sequence_length)`, *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)
+        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.
+"""
+
+LONGT5_DECODE_INPUTS_DOCSTRING = r"""
+    Args:
+        decoder_input_ids (`jnp.ndarray` of shape `(batch_size, target_sequence_length)`):
+            Indices of decoder input sequence tokens in the vocabulary.
+
+            Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
+            [`PreTrainedTokenizer.__call__`] for details.
+
+            [What are decoder input IDs?](../glossary#decoder-input-ids)
+
+            For training, `decoder_input_ids` should be provided.
+        encoder_outputs (`tuple(tuple(jnp.ndarray)`):
+            Tuple consists of (`last_hidden_state`, *optional*: `hidden_states`, *optional*: `attentions`)
+            `last_hidden_state` of shape `(batch_size, sequence_length, hidden_size)`, *optional*) is a sequence of
+            hidden-states at the output of the last layer of the encoder. Used in the cross-attention of the decoder.
+        encoder_attention_mask (`jnp.ndarray` of shape `(batch_size, sequence_length)`, *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)
+        decoder_attention_mask (`jnp.ndarray` of shape `(batch_size, target_sequence_length)`, *optional*):
+            Default behavior: generate a tensor that ignores pad tokens in `decoder_input_ids`. Causal mask will also
+            be used by default.
+
+            If you want to change padding behavior, you should modify to your needs. See diagram 1 in [the
+            paper](https://arxiv.org/abs/1910.13461) for more information on the default strategy.
+        past_key_values (`Dict[str, np.ndarray]`, *optional*, returned by `init_cache` or when passing previous `past_key_values`):
+            Dictionary of pre-computed hidden-states (key and values in the attention blocks) that can be used for fast
+            auto-regressive decoding. Pre-computed key and value hidden-states are of shape *[batch_size, max_length]*.
+        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.
+"""
+
+
+LONGT5_INPUTS_DOCSTRING = r"""
+    Args:
+        input_ids (`jnp.ndarray` of shape `(batch_size, sequence_length)`):
+            Indices of input sequence tokens in the vocabulary. LongT5 is a model with relative position embeddings so
+            you should be able to pad the inputs on both the right and the left.
+
+            Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
+            [`PreTrainedTokenizer.__call__`] for detail.
+
+            [What are input IDs?](../glossary#input-ids)
+
+            To know more on how to prepare `input_ids` for pretraining take a look a [LONGT5
+            Training](./longt5#training).
+        attention_mask (`jnp.ndarray` of shape `(batch_size, sequence_length)`, *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)
+        decoder_input_ids (`jnp.ndarray` of shape `(batch_size, target_sequence_length)`, *optional*):
+            Indices of decoder input sequence tokens in the vocabulary.
+
+            Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
+            [`PreTrainedTokenizer.__call__`] for details.
+
+            [What are decoder input IDs?](../glossary#decoder-input-ids)
+
+            LONGT5 uses the `pad_token_id` as the starting token for `decoder_input_ids` generation. If
+            `past_key_values` is used, optionally only the last `decoder_input_ids` have to be input (see
+            `past_key_values`).
+
+            To know more on how to prepare `decoder_input_ids` for pretraining take a look at [LONGT5
+            Training](./longt5#training).
+        decoder_attention_mask (`jnp.ndarray` of shape `(batch_size, target_sequence_length)`, *optional*):
+            Default behavior: generate a tensor that ignores pad tokens in `decoder_input_ids`. Causal mask will also
+            be used by default.
+        encoder_outputs (`tuple(tuple(jnp.ndarray)`, *optional*):
+            Tuple consists of (`last_hidden_state`, `optional`: *hidden_states*, `optional`: *attentions*)
+            `last_hidden_state` of shape `(batch_size, sequence_length, hidden_size)` is a sequence of hidden states at
+            the output of the last layer of the encoder. Used in the cross-attention of the decoder.
+        past_key_values (`tuple(tuple(jnp.ndarray))` of length `config.n_layers` with each tuple having 4 tensors of shape `(batch_size, num_heads, sequence_length - 1, embed_size_per_head)`):
+            Contains precomputed key and value hidden states of the attention blocks. Can be used to speed up decoding.
+
+            If `past_key_values` are used, the user can optionally input only the last `decoder_input_ids` (those that
+            don't have their past key value states given to this model) of shape `(batch_size, 1)` instead of all
+            `decoder_input_ids` of shape `(batch_size, sequence_length)`.
+
+
+        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.
+"""
+
+
+class FlaxLongT5PreTrainedModel(FlaxPreTrainedModel):
+    """
+    An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained
+    models.
+    """
+
+    config_class = LongT5Config
+    base_model_prefix = "transformer"
+    module_class: nn.Module = None
+
+    def __init__(
+        self,
+        config: LongT5Config,
+        input_shape: Tuple[int] = (1, 1),
+        seed: int = 0,
+        dtype: jnp.dtype = jnp.float32,
+        _do_init: bool = True,
+        **kwargs,
+    ):
+        module = self.module_class(config=config, dtype=dtype, **kwargs)
+        super().__init__(config, module, input_shape=input_shape, seed=seed, dtype=dtype, _do_init=_do_init)
+
+    def enable_gradient_checkpointing(self):
+        self._module = self.module_class(
+            config=self.config,
+            dtype=self.dtype,
+            gradient_checkpointing=True,
+        )
+
+    def init_weights(self, rng: jax.random.PRNGKey, input_shape: Tuple, params: FrozenDict = None) -> FrozenDict:
+        # init input tensors
+        input_ids = jnp.zeros(input_shape, dtype="i4")
+
+        attention_mask = jnp.ones_like(input_ids)
+        decoder_input_ids = jnp.ones_like(input_ids)
+        decoder_attention_mask = jnp.ones_like(input_ids)
+
+        params_rng, dropout_rng = jax.random.split(rng)
+        rngs = {"params": params_rng, "dropout": dropout_rng}
+
+        random_params = self.module.init(
+            rngs,
+            input_ids,
+            attention_mask,
+            decoder_input_ids,
+            decoder_attention_mask,
+        )["params"]
+
+        if params is not None:
+            random_params = flatten_dict(unfreeze(random_params))
+            params = flatten_dict(unfreeze(params))
+            for missing_key in self._missing_keys:
+                params[missing_key] = random_params[missing_key]
+            self._missing_keys = set()
+            return freeze(unflatten_dict(params))
+        else:
+            return random_params
+
+    @add_start_docstrings_to_model_forward(LONGT5_INPUTS_DOCSTRING)
+    def __call__(
+        self,
+        input_ids: jnp.ndarray,
+        attention_mask: Optional[jnp.ndarray] = None,
+        decoder_input_ids: jnp.ndarray = None,
+        decoder_attention_mask: Optional[jnp.ndarray] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        return_dict: Optional[bool] = None,
+        train: bool = False,
+        params: dict = None,
+        dropout_rng: PRNGKey = None,
+    ):
+        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.return_dict
+
+        if decoder_input_ids is None:
+            raise ValueError(
+                "Make sure to provide both `input_ids` and `decoder_input_ids`. `decoder_input_ids` is not passed"
+                " here."
+            )
+
+        # prepare encoder inputs
+        if attention_mask is None:
+            attention_mask = jnp.ones_like(input_ids)
+
+        # prepare decoder inputs
+        if decoder_attention_mask is None:
+            decoder_attention_mask = jnp.ones_like(decoder_input_ids)
+
+        # Handle any PRNG if needed
+        rngs = {"dropout": dropout_rng} if dropout_rng is not None else {}
+
+        return self.module.apply(
+            {"params": params or self.params},
+            input_ids=jnp.array(input_ids, dtype="i4"),
+            attention_mask=jnp.array(attention_mask, dtype="i4"),
+            decoder_input_ids=jnp.array(decoder_input_ids, dtype="i4"),
+            decoder_attention_mask=jnp.array(decoder_attention_mask, dtype="i4"),
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=return_dict,
+            deterministic=not train,
+            rngs=rngs,
+        )
+
+    def init_cache(self, batch_size, max_length, encoder_outputs):
+        r"""
+        Args:
+            batch_size (`int`):
+                batch_size used for fast auto-regressive decoding. Defines the batch size of the initialized cache.
+            max_length (`int`):
+                maximum possible length for auto-regressive decoding. Defines the sequence length of the initialized
+                cache.
+            encoder_outputs (`Union[FlaxBaseModelOutput, tuple(tuple(jnp.ndarray)]`):
+                `encoder_outputs` consists of (`last_hidden_state`, *optional*: `hidden_states`, *optional*:
+                `attentions`). `last_hidden_state` of shape `(batch_size, sequence_length, hidden_size)`, *optional*)
+                is a sequence of hidden-states at the output of the last layer of the encoder. Used in the
+                cross-attention of the decoder.
+        """
+        # init input variables to retrieve cache
+        decoder_input_ids = jnp.ones((batch_size, max_length), dtype="i4")
+        decoder_attention_mask = jnp.ones_like(decoder_input_ids)
+
+        def _decoder_forward(module, decoder_input_ids, decoder_attention_mask, **kwargs):
+            decoder_module = module._get_decoder_module()
+            return decoder_module(
+                decoder_input_ids,
+                decoder_attention_mask,
+                **kwargs,
+            )
+
+        init_variables = self.module.init(
+            jax.random.PRNGKey(0),
+            decoder_input_ids=decoder_input_ids,
+            decoder_attention_mask=decoder_attention_mask,
+            encoder_hidden_states=encoder_outputs[0],
+            init_cache=True,
+            method=_decoder_forward,  # we only need to call the decoder to init the cache
+        )
+        return unfreeze(init_variables["cache"])
+
+    @add_start_docstrings(LONGT5_ENCODE_INPUTS_DOCSTRING)
+    @replace_return_docstrings(output_type=FlaxBaseModelOutput, config_class=LongT5Config)
+    def encode(
+        self,
+        input_ids: jnp.ndarray,
+        attention_mask: Optional[jnp.ndarray] = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        return_dict: Optional[bool] = None,
+        train: bool = False,
+        params: dict = None,
+        dropout_rng: PRNGKey = None,
+    ):
+        r"""
+        Returns:
+
+        Example:
+
+        ```python
+        >>> from transformers import AutoTokenizer, FlaxLongT5ForConditionalGeneration
+
+        >>> tokenizer = AutoTokenizer.from_pretrained("google-t5/t5-base")
+        >>> model = FlaxLongT5ForConditionalGeneration.from_pretrained("google/long-t5-local-base")
+
+        >>> text = "My friends are cool but they eat too many carbs."
+        >>> inputs = tokenizer(text, return_tensors="np")
+        >>> encoder_outputs = model.encode(**inputs)
+        ```"""
+        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.return_dict
+
+        if attention_mask is None:
+            attention_mask = jnp.ones_like(input_ids)
+
+        # Handle any PRNG if needed
+        rngs = {}
+        if dropout_rng is not None:
+            rngs["dropout"] = dropout_rng
+
+        def _encoder_forward(module, input_ids, attention_mask, **kwargs):
+            encode_module = module._get_encoder_module()
+            return encode_module(input_ids, attention_mask, **kwargs)
+
+        return self.module.apply(
+            {"params": params or self.params},
+            input_ids=jnp.array(input_ids, dtype="i4"),
+            attention_mask=jnp.array(attention_mask, dtype="i4"),
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=return_dict,
+            deterministic=not train,
+            rngs=rngs,
+            method=_encoder_forward,
+        )
+
+    @add_start_docstrings(LONGT5_DECODE_INPUTS_DOCSTRING)
+    @replace_return_docstrings(output_type=FlaxBaseModelOutputWithPastAndCrossAttentions, config_class=LongT5Config)
+    def decode(
+        self,
+        decoder_input_ids,
+        encoder_outputs,
+        encoder_attention_mask: Optional[jnp.ndarray] = None,
+        decoder_attention_mask: Optional[jnp.ndarray] = None,
+        past_key_values: dict = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        return_dict: Optional[bool] = None,
+        train: bool = False,
+        params: dict = None,
+        dropout_rng: PRNGKey = None,
+    ):
+        r"""
+        Returns:
+
+        Example:
+
+        ```python
+        >>> from transformers import AutoTokenizer, FlaxLongT5ForConditionalGeneration
+        >>> import jax.numpy as jnp
+
+        >>> tokenizer = AutoTokenizer.from_pretrained("google-t5/t5-base")
+        >>> model = FlaxLongT5ForConditionalGeneration.from_pretrained("google/long-t5-local-base")
+
+        >>> text = "My friends are cool but they eat too many carbs."
+        >>> inputs = tokenizer(text, return_tensors="np")
+        >>> encoder_outputs = model.encode(**inputs)
+
+        >>> decoder_start_token_id = model.config.decoder_start_token_id
+        >>> decoder_input_ids = jnp.ones((inputs.input_ids.shape[0], 1), dtype="i4") * decoder_start_token_id
+
+        >>> outputs = model.decode(decoder_input_ids, encoder_outputs)
+        >>> logits = outputs.logits
+        ```"""
+        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.return_dict
+
+        encoder_hidden_states = encoder_outputs[0]
+        if encoder_attention_mask is None:
+            batch_size, sequence_length = encoder_hidden_states.shape[:2]
+            encoder_attention_mask = jnp.ones((batch_size, sequence_length))
+
+        batch_size, sequence_length = decoder_input_ids.shape
+        if decoder_attention_mask is None:
+            decoder_attention_mask = jnp.ones((batch_size, sequence_length))
+
+        # Handle any PRNG if needed
+        rngs = {}
+        if dropout_rng is not None:
+            rngs["dropout"] = dropout_rng
+
+        inputs = {"params": params or self.params}
+
+        # if past_key_values are passed then cache is already initialized a private flag init_cache has to be
+        # passed down to ensure cache is used. It has to be made sure that cache is marked as mutable so that
+        # it can be changed by FlaxLongT5Attention module
+        if past_key_values:
+            inputs["cache"] = past_key_values
+            mutable = ["cache"]
+        else:
+            mutable = False
+
+        def _decoder_forward(module, decoder_input_ids, decoder_attention_mask, **kwargs):
+            decoder_module = module._get_decoder_module()
+            return decoder_module(
+                decoder_input_ids,
+                decoder_attention_mask,
+                **kwargs,
+            )
+
+        outputs = self.module.apply(
+            inputs,
+            decoder_input_ids=jnp.array(decoder_input_ids, dtype="i4"),
+            decoder_attention_mask=jnp.array(decoder_attention_mask, dtype="i4"),
+            encoder_hidden_states=encoder_hidden_states,
+            encoder_attention_mask=jnp.array(encoder_attention_mask, dtype="i4"),
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=return_dict,
+            deterministic=not train,
+            rngs=rngs,
+            mutable=mutable,
+            method=_decoder_forward,
+        )
+
+        # add updated cache to model output
+        if past_key_values is not None and return_dict:
+            outputs, past = outputs
+            outputs["past_key_values"] = unfreeze(past["cache"])
+            return outputs
+        elif past_key_values is not None and not return_dict:
+            outputs, past = outputs
+            outputs = outputs[:1] + (unfreeze(past["cache"]),) + outputs[1:]
+
+        return outputs
+
+
+LONGT5_START_DOCSTRING = r"""
+    The LongT5 model was proposed in [LongT5: Efficient Text-To-Text Transformer for Long
+    Sequences](https://arxiv.org/abs/2112.07916) by Mandy Guo, Joshua Ainslie, David Uthus, Santiago Ontanon, Jianmo
+    Ni, Yun-Hsuan Sung and Yinfei Yang. It's an encoder-decoder transformer pre-trained in a text-to-text denoising
+    generative setting. LongT5 model is an extension of T5 model, and it enables using one of the two different
+    efficient attention mechanisms - (1) Local attention, or (2) Transient-Global attention.
+
+    This model inherits from [`FlaxPreTrainedModel`]. Check the superclass documentation for the generic methods the
+    library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads
+    etc.)
+
+    This model is also a Flax Linen
+    [flax.nn.Module](https://flax.readthedocs.io/en/latest/_autosummary/flax.nn.module.html) subclass. Use it as a
+    regular Flax Module and refer to the Flax documentation for all matter related to general usage and behavior.
+
+    Finally, this model supports inherent JAX features such as:
+
+    - [Just-In-Time (JIT) compilation](https://jax.readthedocs.io/en/latest/jax.html#just-in-time-compilation-jit)
+    - [Automatic Differentiation](https://jax.readthedocs.io/en/latest/jax.html#automatic-differentiation)
+    - [Vectorization](https://jax.readthedocs.io/en/latest/jax.html#vectorization-vmap)
+    - [Parallelization](https://jax.readthedocs.io/en/latest/jax.html#parallelization-pmap)
+
+    Parameters:
+        config ([`LongT5Config`]): 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 [`~FlaxPreTrainedModel.from_pretrained`] method to load the model weights.
+        dtype (`jax.numpy.dtype`, *optional*, defaults to `jax.numpy.float32`):
+            The data type of the computation. Can be one of `jax.numpy.float32`, `jax.numpy.float16` (on GPUs) and
+            `jax.numpy.bfloat16` (on TPUs).
+
+            This can be used to enable mixed-precision training or half-precision inference on GPUs or TPUs. If
+            specified all the computation will be performed with the given `dtype`.
+
+            **Note that this only specifies the dtype of the computation and does not influence the dtype of model
+            parameters.**
+
+            If you wish to change the dtype of the model parameters, see [`~FlaxPreTrainedModel.to_fp16`] and
+            [`~FlaxPreTrainedModel.to_bf16`].
+"""
+
+
+@add_start_docstrings(
+    "The bare LONGT5 Model transformer outputting raw hidden-stateswithout any specific head on top.",
+    LONGT5_START_DOCSTRING,
+)
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5Module with T5->LongT5
+class FlaxLongT5Module(nn.Module):
+    config: LongT5Config
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+    gradient_checkpointing: bool = False
+
+    def _get_encoder_module(self):
+        return self.encoder
+
+    def _get_decoder_module(self):
+        return self.decoder
+
+    def setup(self):
+        self.shared = nn.Embed(
+            self.config.vocab_size,
+            self.config.d_model,
+            embedding_init=jax.nn.initializers.normal(self.config.initializer_factor * 1.0),
+            dtype=self.dtype,
+        )
+
+        encoder_config = copy.deepcopy(self.config)
+        encoder_config.causal = False
+        self.encoder = FlaxLongT5Stack(
+            encoder_config,
+            embed_tokens=self.shared,
+            dtype=self.dtype,
+            gradient_checkpointing=self.gradient_checkpointing,
+        )
+
+        decoder_config = copy.deepcopy(self.config)
+        decoder_config.causal = True
+        decoder_config.num_layers = self.config.num_decoder_layers
+        self.decoder = FlaxLongT5Stack(
+            decoder_config,
+            embed_tokens=self.shared,
+            dtype=self.dtype,
+            gradient_checkpointing=self.gradient_checkpointing,
+        )
+
+    def __call__(
+        self,
+        input_ids=None,
+        attention_mask=None,
+        decoder_input_ids=None,
+        decoder_attention_mask=None,
+        encoder_outputs=None,
+        output_attentions=None,
+        output_hidden_states=None,
+        return_dict=None,
+        deterministic: bool = True,
+    ):
+        return_dict = return_dict if return_dict is not None else self.config.use_return_dict
+
+        # Encode if needed (training, first prediction pass)
+        encoder_outputs = self.encoder(
+            input_ids=input_ids,
+            attention_mask=attention_mask,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=return_dict,
+            deterministic=deterministic,
+        )
+
+        # Decode
+        decoder_outputs = self.decoder(
+            input_ids=decoder_input_ids,
+            attention_mask=decoder_attention_mask,
+            encoder_hidden_states=encoder_outputs[0],
+            encoder_attention_mask=attention_mask,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=return_dict,
+            deterministic=deterministic,
+        )
+
+        if not return_dict:
+            return decoder_outputs + encoder_outputs
+
+        return FlaxSeq2SeqModelOutput(
+            last_hidden_state=decoder_outputs.last_hidden_state,
+            past_key_values=decoder_outputs.past_key_values,
+            decoder_hidden_states=decoder_outputs.hidden_states,
+            decoder_attentions=decoder_outputs.attentions,
+            cross_attentions=decoder_outputs.cross_attentions,
+            encoder_last_hidden_state=encoder_outputs.last_hidden_state,
+            encoder_hidden_states=encoder_outputs.hidden_states,
+            encoder_attentions=encoder_outputs.attentions,
+        )
+
+
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5Model with T5->LongT5
+class FlaxLongT5Model(FlaxLongT5PreTrainedModel):
+    module_class = FlaxLongT5Module
+
+
+append_call_sample_docstring(FlaxLongT5Model, _CHECKPOINT_FOR_DOC, FlaxSeq2SeqModelOutput, _CONFIG_FOR_DOC)
+
+FLAX_LONGT5_MODEL_DOCSTRING = """
+    Returns:
+
+    Example:
+
+    ```python
+    >>> from transformers import AutoTokenizer, FlaxLongT5Model
+
+    >>> tokenizer = AutoTokenizer.from_pretrained("google-t5/t5-base")
+    >>> model = FlaxLongT5Model.from_pretrained("google/long-t5-local-base")
+
+    >>> input_ids = tokenizer(
+    ...     "Studies have been shown that owning a dog is good for you", return_tensors="np"
+    ... ).input_ids
+    >>> decoder_input_ids = tokenizer("Studies show that", return_tensors="np").input_ids
+
+    >>> # forward pass
+    >>> outputs = model(input_ids=input_ids, decoder_input_ids=decoder_input_ids)
+    >>> last_hidden_states = outputs.last_hidden_state
+    ```
+"""
+
+
+overwrite_call_docstring(FlaxLongT5Model, LONGT5_INPUTS_DOCSTRING + FLAX_LONGT5_MODEL_DOCSTRING)
+append_replace_return_docstrings(FlaxLongT5Model, output_type=FlaxSeq2SeqLMOutput, config_class=_CONFIG_FOR_DOC)
+
+
+@add_start_docstrings("""LONGT5 Model with a `language modeling` head on top.""", LONGT5_START_DOCSTRING)
+# Copied from transformers.models.t5.modeling_flax_t5.FlaxT5ForConditionalGenerationModule with T5->LongT5
+class FlaxLongT5ForConditionalGenerationModule(nn.Module):
+    config: LongT5Config
+    dtype: jnp.dtype = jnp.float32  # the dtype of the computation
+    gradient_checkpointing: bool = False
+
+    def _get_encoder_module(self):
+        return self.encoder
+
+    def _get_decoder_module(self):
+        return self.decoder
+
+    def setup(self):
+        self.model_dim = self.config.d_model
+
+        self.shared = nn.Embed(
+            self.config.vocab_size,
+            self.config.d_model,
+            embedding_init=jax.nn.initializers.normal(self.config.initializer_factor),
+            dtype=self.dtype,
+        )
+
+        encoder_config = copy.deepcopy(self.config)
+        encoder_config.causal = False
+        encoder_config.use_cache = False
+        encoder_config.is_encoder_decoder = False
+        self.encoder = FlaxLongT5Stack(
+            encoder_config, self.shared, dtype=self.dtype, gradient_checkpointing=self.gradient_checkpointing
+        )
+
+        decoder_config = copy.deepcopy(self.config)
+        decoder_config.causal = True
+        decoder_config.is_encoder_decoder = False
+        decoder_config.num_layers = self.config.num_decoder_layers
+        self.decoder = FlaxLongT5Stack(
+            decoder_config, self.shared, dtype=self.dtype, gradient_checkpointing=self.gradient_checkpointing
+        )
+
+        self.lm_head = nn.Dense(
+            self.config.vocab_size,
+            use_bias=False,
+            kernel_init=jax.nn.initializers.normal(self.config.initializer_factor),
+            dtype=self.dtype,
+        )
+
+    def __call__(
+        self,
+        input_ids=None,
+        attention_mask=None,
+        decoder_input_ids=None,
+        decoder_attention_mask=None,
+        encoder_outputs=None,
+        output_attentions=None,
+        output_hidden_states=None,
+        return_dict=None,
+        deterministic: bool = True,
+    ):
+        return_dict = return_dict if return_dict is not None else self.config.use_return_dict
+
+        # Encode
+        encoder_outputs = self.encoder(
+            input_ids=input_ids,
+            attention_mask=attention_mask,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=return_dict,
+            deterministic=deterministic,
+        )
+
+        hidden_states = encoder_outputs[0]
+
+        # Decode
+        decoder_outputs = self.decoder(
+            input_ids=decoder_input_ids,
+            attention_mask=decoder_attention_mask,
+            encoder_hidden_states=hidden_states,
+            encoder_attention_mask=attention_mask,
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=return_dict,
+            deterministic=deterministic,
+        )
+
+        sequence_output = decoder_outputs[0]
+
+        if self.config.tie_word_embeddings:
+            # Rescale output before projecting on vocab
+            # See https://github.com/tensorflow/mesh/blob/fa19d69eafc9a482aff0b59ddd96b025c0cb207d/mesh_tensorflow/transformer/transformer.py#L586
+            sequence_output = sequence_output * (self.model_dim**-0.5)
+
+        if self.config.tie_word_embeddings:
+            shared_embedding = self.shared.variables["params"]["embedding"]
+            lm_logits = self.lm_head.apply({"params": {"kernel": shared_embedding.T}}, sequence_output)
+        else:
+            lm_logits = self.lm_head(sequence_output)
+
+        if not return_dict:
+            return (lm_logits,) + decoder_outputs[1:] + encoder_outputs
+
+        return FlaxSeq2SeqLMOutput(
+            logits=lm_logits,
+            past_key_values=decoder_outputs.past_key_values,
+            decoder_hidden_states=decoder_outputs.hidden_states,
+            decoder_attentions=decoder_outputs.attentions,
+            cross_attentions=decoder_outputs.cross_attentions,
+            encoder_last_hidden_state=encoder_outputs.last_hidden_state,
+            encoder_hidden_states=encoder_outputs.hidden_states,
+            encoder_attentions=encoder_outputs.attentions,
+        )
+
+
+class FlaxLongT5ForConditionalGeneration(FlaxLongT5PreTrainedModel):
+    module_class = FlaxLongT5ForConditionalGenerationModule
+
+    @add_start_docstrings(LONGT5_DECODE_INPUTS_DOCSTRING)
+    @replace_return_docstrings(output_type=FlaxCausalLMOutputWithCrossAttentions, config_class=LongT5Config)
+    def decode(
+        self,
+        decoder_input_ids,
+        encoder_outputs,
+        encoder_attention_mask: Optional[jnp.ndarray] = None,
+        decoder_attention_mask: Optional[jnp.ndarray] = None,
+        past_key_values: dict = None,
+        output_attentions: Optional[bool] = None,
+        output_hidden_states: Optional[bool] = None,
+        return_dict: Optional[bool] = None,
+        train: bool = False,
+        params: dict = None,
+        dropout_rng: PRNGKey = None,
+    ):
+        r"""
+        Returns:
+
+        Example:
+
+        ```python
+        >>> from transformers import AutoTokenizer, FlaxLongT5ForConditionalGeneration
+        >>> import jax.numpy as jnp
+
+        >>> tokenizer = AutoTokenizer.from_pretrained("google-t5/t5-base")
+        >>> model = FlaxLongT5ForConditionalGeneration.from_pretrained("google/long-t5-local-base")
+
+        >>> text = "summarize: My friends are cool but they eat too many carbs."
+        >>> inputs = tokenizer(text, return_tensors="np")
+        >>> encoder_outputs = model.encode(**inputs)
+
+        >>> decoder_start_token_id = model.config.decoder_start_token_id
+        >>> decoder_input_ids = jnp.ones((inputs.input_ids.shape[0], 1), dtype="i4") * decoder_start_token_id
+
+        >>> outputs = model.decode(decoder_input_ids, encoder_outputs)
+        >>> logits = outputs.logits
+        ```"""
+        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.return_dict
+
+        encoder_hidden_states = encoder_outputs[0]
+        if encoder_attention_mask is None:
+            batch_size, sequence_length = encoder_hidden_states.shape[:2]
+            encoder_attention_mask = jnp.ones((batch_size, sequence_length))
+
+        batch_size, sequence_length = decoder_input_ids.shape
+        if decoder_attention_mask is None:
+            decoder_attention_mask = jnp.ones((batch_size, sequence_length))
+
+        # Handle any PRNG if needed
+        rngs = {}
+        if dropout_rng is not None:
+            rngs["dropout"] = dropout_rng
+
+        inputs = {"params": params or self.params}
+
+        # if past_key_values are passed then cache is already initialized a private flag init_cache has to be
+        # passed down to ensure cache is used. It has to be made sure that cache is marked as mutable so that
+        # it can be changed by FlaxLongT5Attention module
+        if past_key_values:
+            inputs["cache"] = past_key_values
+            mutable = ["cache"]
+        else:
+            mutable = False
+
+        def _decoder_forward(module, decoder_input_ids, decoder_attention_mask, **kwargs):
+            decoder_module = module._get_decoder_module()
+            decoder_outputs = decoder_module(
+                decoder_input_ids,
+                decoder_attention_mask,
+                **kwargs,
+            )
+
+            sequence_output = decoder_outputs[0]
+
+            if self.config.tie_word_embeddings:
+                # Rescale output before projecting on vocab
+                # See https://github.com/tensorflow/mesh/blob/fa19d69eafc9a482aff0b59ddd96b025c0cb207d/mesh_tensorflow/transformer/transformer.py#L586
+                sequence_output = sequence_output * (self.config.d_model**-0.5)
+
+            if self.config.tie_word_embeddings:
+                shared_embedding = module.shared.variables["params"]["embedding"]
+                lm_logits = module.lm_head.apply({"params": {"kernel": shared_embedding.T}}, sequence_output)
+            else:
+                lm_logits = module.lm_head(sequence_output)
+
+            return lm_logits, decoder_outputs
+
+        outputs = self.module.apply(
+            inputs,
+            decoder_input_ids=jnp.array(decoder_input_ids, dtype="i4"),
+            decoder_attention_mask=jnp.array(decoder_attention_mask, dtype="i4"),
+            encoder_hidden_states=encoder_hidden_states,
+            encoder_attention_mask=jnp.array(encoder_attention_mask, dtype="i4"),
+            output_attentions=output_attentions,
+            output_hidden_states=output_hidden_states,
+            return_dict=return_dict,
+            deterministic=not train,
+            rngs=rngs,
+            mutable=mutable,
+            method=_decoder_forward,
+        )
+
+        if past_key_values is None:
+            lm_logits, decoder_outputs = outputs
+        else:
+            (lm_logits, decoder_outputs), past = outputs
+
+        if return_dict:
+            outputs = FlaxCausalLMOutputWithCrossAttentions(
+                logits=lm_logits,
+                hidden_states=decoder_outputs.hidden_states,
+                attentions=decoder_outputs.attentions,
+                cross_attentions=decoder_outputs.cross_attentions,
+            )
+        else:
+            outputs = (lm_logits,) + decoder_outputs[1:]
+
+        # add updated cache to model output
+        if past_key_values is not None and return_dict:
+            outputs["past_key_values"] = unfreeze(past["cache"])
+            return outputs
+        elif past_key_values is not None and not return_dict:
+            outputs = outputs[:1] + (unfreeze(past["cache"]),) + outputs[1:]
+
+        return outputs
+
+    def prepare_inputs_for_generation(
+        self,
+        decoder_input_ids,
+        max_length,
+        attention_mask: Optional[jax.Array] = None,
+        decoder_attention_mask: Optional[jax.Array] = None,
+        encoder_outputs=None,
+        **kwargs,
+    ):
+        # initializing the cache
+        batch_size, seq_length = decoder_input_ids.shape
+
+        past_key_values = self.init_cache(batch_size, max_length, encoder_outputs)
+        # Note that usually one would have to put 0's in the attention_mask for x > input_ids.shape[-1] and x < cache_length.
+        # But since the decoder uses a causal mask, those positions are masked anyways.
+        # Thus we can create a single static attention_mask here, which is more efficient for compilation
+        extended_attention_mask = jnp.ones((batch_size, max_length), dtype="i4")
+        if decoder_attention_mask is not None:
+            extended_attention_mask = jax.lax.dynamic_update_slice(
+                extended_attention_mask, decoder_attention_mask, (0, 0)
+            )
+
+        return {
+            "past_key_values": past_key_values,
+            "encoder_outputs": encoder_outputs,
+            "encoder_attention_mask": attention_mask,
+            "decoder_attention_mask": extended_attention_mask,
+        }
+
+    def update_inputs_for_generation(self, model_outputs, model_kwargs):
+        model_kwargs["past_key_values"] = model_outputs.past_key_values
+        return model_kwargs
+
+
+FLAX_LONGT5_CONDITIONAL_GENERATION_DOCSTRING = """
+    Returns:
+
+    Example:
+
+    ```python
+    >>> from transformers import AutoTokenizer, FlaxLongT5ForConditionalGeneration
+
+    >>> tokenizer = AutoTokenizer.from_pretrained("google-t5/t5-base")
+    >>> model = FlaxLongT5ForConditionalGeneration.from_pretrained("google/long-t5-local-base")
+
+    >>> ARTICLE_TO_SUMMARIZE = "summarize: My friends are cool but they eat too many carbs."
+    >>> inputs = tokenizer([ARTICLE_TO_SUMMARIZE], return_tensors="np")
+
+    >>> # Generate Summary
+    >>> summary_ids = model.generate(inputs["input_ids"]).sequences
+    >>> print(tokenizer.decode(summary_ids[0], skip_special_tokens=True, clean_up_tokenization_spaces=False))
+    ```
+"""
+
+
+overwrite_call_docstring(
+    FlaxLongT5ForConditionalGeneration, LONGT5_INPUTS_DOCSTRING + FLAX_LONGT5_CONDITIONAL_GENERATION_DOCSTRING
+)
+append_replace_return_docstrings(
+    FlaxLongT5ForConditionalGeneration, output_type=FlaxSeq2SeqLMOutput, config_class=_CONFIG_FOR_DOC
+)