| from typing import * | |
| import torch | |
| class ClassifierFreeGuidanceSamplerMixin: | |
| """ | |
| A mixin class for samplers that apply classifier-free guidance. | |
| """ | |
| def _inference_model(self, model, x_t, t, cond, neg_cond, cfg_strength, **kwargs): | |
| pred = super()._inference_model(model, x_t, t, cond, **kwargs) | |
| if 'masks' in kwargs: | |
| kwargs['masks'] = torch.zeros_like(kwargs['masks']) | |
| neg_pred = super()._inference_model(model, x_t, t, neg_cond, **kwargs) | |
| return (1 + cfg_strength) * pred - cfg_strength * neg_pred | |