File size: 7,984 Bytes
0324143
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
# Copyright 2024 The HuggingFace Team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import Optional, Tuple, Union

import torch
import torch.nn as nn

from ...configuration_utils import ConfigMixin, register_to_config
from ...utils.accelerate_utils import apply_forward_hook
from ..modeling_outputs import AutoencoderKLOutput
from ..modeling_utils import ModelMixin
from .vae import DecoderOutput, DiagonalGaussianDistribution, Encoder, MaskConditionDecoder


class AsymmetricAutoencoderKL(ModelMixin, ConfigMixin):
    r"""

    Designing a Better Asymmetric VQGAN for StableDiffusion https://arxiv.org/abs/2306.04632 . A VAE model with KL loss

    for encoding images into latents and decoding latent representations into images.



    This model inherits from [`ModelMixin`]. Check the superclass documentation for it's generic methods implemented

    for all models (such as downloading or saving).



    Parameters:

        in_channels (int, *optional*, defaults to 3): Number of channels in the input image.

        out_channels (int,  *optional*, defaults to 3): Number of channels in the output.

        down_block_types (`Tuple[str]`, *optional*, defaults to `("DownEncoderBlock2D",)`):

            Tuple of downsample block types.

        down_block_out_channels (`Tuple[int]`, *optional*, defaults to `(64,)`):

            Tuple of down block output channels.

        layers_per_down_block (`int`, *optional*, defaults to `1`):

            Number layers for down block.

        up_block_types (`Tuple[str]`, *optional*, defaults to `("UpDecoderBlock2D",)`):

            Tuple of upsample block types.

        up_block_out_channels (`Tuple[int]`, *optional*, defaults to `(64,)`):

            Tuple of up block output channels.

        layers_per_up_block (`int`, *optional*, defaults to `1`):

            Number layers for up block.

        act_fn (`str`, *optional*, defaults to `"silu"`): The activation function to use.

        latent_channels (`int`, *optional*, defaults to 4): Number of channels in the latent space.

        sample_size (`int`, *optional*, defaults to `32`): Sample input size.

        norm_num_groups (`int`, *optional*, defaults to `32`):

            Number of groups to use for the first normalization layer in ResNet blocks.

        scaling_factor (`float`, *optional*, defaults to 0.18215):

            The component-wise standard deviation of the trained latent space computed using the first batch of the

            training set. This is used to scale the latent space to have unit variance when training the diffusion

            model. The latents are scaled with the formula `z = z * scaling_factor` before being passed to the

            diffusion model. When decoding, the latents are scaled back to the original scale with the formula: `z = 1

            / scaling_factor * z`. For more details, refer to sections 4.3.2 and D.1 of the [High-Resolution Image

            Synthesis with Latent Diffusion Models](https://arxiv.org/abs/2112.10752) paper.

    """

    @register_to_config
    def __init__(

        self,

        in_channels: int = 3,

        out_channels: int = 3,

        down_block_types: Tuple[str, ...] = ("DownEncoderBlock2D",),

        down_block_out_channels: Tuple[int, ...] = (64,),

        layers_per_down_block: int = 1,

        up_block_types: Tuple[str, ...] = ("UpDecoderBlock2D",),

        up_block_out_channels: Tuple[int, ...] = (64,),

        layers_per_up_block: int = 1,

        act_fn: str = "silu",

        latent_channels: int = 4,

        norm_num_groups: int = 32,

        sample_size: int = 32,

        scaling_factor: float = 0.18215,

    ) -> None:
        super().__init__()

        # pass init params to Encoder
        self.encoder = Encoder(
            in_channels=in_channels,
            out_channels=latent_channels,
            down_block_types=down_block_types,
            block_out_channels=down_block_out_channels,
            layers_per_block=layers_per_down_block,
            act_fn=act_fn,
            norm_num_groups=norm_num_groups,
            double_z=True,
        )

        # pass init params to Decoder
        self.decoder = MaskConditionDecoder(
            in_channels=latent_channels,
            out_channels=out_channels,
            up_block_types=up_block_types,
            block_out_channels=up_block_out_channels,
            layers_per_block=layers_per_up_block,
            act_fn=act_fn,
            norm_num_groups=norm_num_groups,
        )

        self.quant_conv = nn.Conv2d(2 * latent_channels, 2 * latent_channels, 1)
        self.post_quant_conv = nn.Conv2d(latent_channels, latent_channels, 1)

        self.use_slicing = False
        self.use_tiling = False

        self.register_to_config(block_out_channels=up_block_out_channels)
        self.register_to_config(force_upcast=False)

    @apply_forward_hook
    def encode(

        self, x: torch.FloatTensor, return_dict: bool = True

    ) -> Union[AutoencoderKLOutput, Tuple[torch.FloatTensor]]:
        h = self.encoder(x)
        moments = self.quant_conv(h)
        posterior = DiagonalGaussianDistribution(moments)

        if not return_dict:
            return (posterior,)

        return AutoencoderKLOutput(latent_dist=posterior)

    def _decode(

        self,

        z: torch.FloatTensor,

        image: Optional[torch.FloatTensor] = None,

        mask: Optional[torch.FloatTensor] = None,

        return_dict: bool = True,

    ) -> Union[DecoderOutput, Tuple[torch.FloatTensor]]:
        z = self.post_quant_conv(z)
        dec = self.decoder(z, image, mask)

        if not return_dict:
            return (dec,)

        return DecoderOutput(sample=dec)

    @apply_forward_hook
    def decode(

        self,

        z: torch.FloatTensor,

        generator: Optional[torch.Generator] = None,

        image: Optional[torch.FloatTensor] = None,

        mask: Optional[torch.FloatTensor] = None,

        return_dict: bool = True,

    ) -> Union[DecoderOutput, Tuple[torch.FloatTensor]]:
        decoded = self._decode(z, image, mask).sample

        if not return_dict:
            return (decoded,)

        return DecoderOutput(sample=decoded)

    def forward(

        self,

        sample: torch.FloatTensor,

        mask: Optional[torch.FloatTensor] = None,

        sample_posterior: bool = False,

        return_dict: bool = True,

        generator: Optional[torch.Generator] = None,

    ) -> Union[DecoderOutput, Tuple[torch.FloatTensor]]:
        r"""

        Args:

            sample (`torch.FloatTensor`): Input sample.

            mask (`torch.FloatTensor`, *optional*, defaults to `None`): Optional inpainting mask.

            sample_posterior (`bool`, *optional*, defaults to `False`):

                Whether to sample from the posterior.

            return_dict (`bool`, *optional*, defaults to `True`):

                Whether or not to return a [`DecoderOutput`] instead of a plain tuple.

        """
        x = sample
        posterior = self.encode(x).latent_dist
        if sample_posterior:
            z = posterior.sample(generator=generator)
        else:
            z = posterior.mode()
        dec = self.decode(z, sample, mask).sample

        if not return_dict:
            return (dec,)

        return DecoderOutput(sample=dec)