549 lines
18 KiB
Python
549 lines
18 KiB
Python
"""The BFL-style Flux2 KL autoencoder (32ch latents, 2x2 pixel-shuffle
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packing to 128ch), shared by the flux2 family and ideogram4.
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flux2 loads the raw BFL ae.safetensors layout and uses encode/decode (with the
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BatchNorm running-stats latent normalization); ideogram4 loads diffusers-format
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checkpoints via convert_diffusers_state_dict and drives encoder/decoder
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directly with its own patchify + latent-norm tables. The two models pack the
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128 latent channels in different orders — the packing/normalization stays
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per-model.
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"""
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from __future__ import annotations
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import math
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import re
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from dataclasses import dataclass, field
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import torch
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import torch.utils.checkpoint as ckpt
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from einops import rearrange
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from torch import Tensor, nn
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from .._mixin import OstrisModelMixin
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@dataclass
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class AutoEncoderParams:
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resolution: int = 256
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in_channels: int = 3
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ch: int = 128
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out_ch: int = 3
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ch_mult: list[int] = field(default_factory=lambda: [1, 2, 4, 4])
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num_res_blocks: int = 2
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z_channels: int = 32
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@dataclass
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class AutoEncoderSmallDecoderParams:
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resolution: int = 256
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in_channels: int = 3
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ch: int = 128
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ch_encoder: int = 96
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out_ch: int = 3
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ch_mult: list[int] = field(default_factory=lambda: [1, 2, 4, 4])
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num_res_blocks: int = 2
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z_channels: int = 32
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def swish(x: Tensor) -> Tensor:
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return x * torch.sigmoid(x)
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class AttnBlock(nn.Module):
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def __init__(self, in_channels: int):
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super().__init__()
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self.in_channels = in_channels
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self.norm = nn.GroupNorm(
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num_groups=32, num_channels=in_channels, eps=1e-6, affine=True
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)
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self.q = nn.Conv2d(in_channels, in_channels, kernel_size=1)
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self.k = nn.Conv2d(in_channels, in_channels, kernel_size=1)
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self.v = nn.Conv2d(in_channels, in_channels, kernel_size=1)
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self.proj_out = nn.Conv2d(in_channels, in_channels, kernel_size=1)
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def attention(self, h_: Tensor) -> Tensor:
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h_ = self.norm(h_)
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q = self.q(h_)
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k = self.k(h_)
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v = self.v(h_)
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b, c, h, w = q.shape
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q = rearrange(q, "b c h w -> b 1 (h w) c").contiguous()
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k = rearrange(k, "b c h w -> b 1 (h w) c").contiguous()
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v = rearrange(v, "b c h w -> b 1 (h w) c").contiguous()
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h_ = nn.functional.scaled_dot_product_attention(q, k, v)
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return rearrange(h_, "b 1 (h w) c -> b c h w", h=h, w=w, c=c, b=b)
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def forward(self, x: Tensor) -> Tensor:
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return x + self.proj_out(self.attention(x))
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class ResnetBlock(nn.Module):
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def __init__(self, in_channels: int, out_channels: int):
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super().__init__()
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self.in_channels = in_channels
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out_channels = in_channels if out_channels is None else out_channels
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self.out_channels = out_channels
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self.norm1 = nn.GroupNorm(
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num_groups=32, num_channels=in_channels, eps=1e-6, affine=True
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)
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self.conv1 = nn.Conv2d(
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in_channels, out_channels, kernel_size=3, stride=1, padding=1
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)
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self.norm2 = nn.GroupNorm(
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num_groups=32, num_channels=out_channels, eps=1e-6, affine=True
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)
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self.conv2 = nn.Conv2d(
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out_channels, out_channels, kernel_size=3, stride=1, padding=1
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)
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if self.in_channels != self.out_channels:
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self.nin_shortcut = nn.Conv2d(
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in_channels, out_channels, kernel_size=1, stride=1, padding=0
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)
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def forward(self, x):
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h = x
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h = self.norm1(h)
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h = swish(h)
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h = self.conv1(h)
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h = self.norm2(h)
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h = swish(h)
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h = self.conv2(h)
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if self.in_channels != self.out_channels:
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x = self.nin_shortcut(x)
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return x + h
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class Downsample(nn.Module):
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def __init__(self, in_channels: int):
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super().__init__()
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# no asymmetric padding in torch conv, must do it ourselves
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self.conv = nn.Conv2d(
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in_channels, in_channels, kernel_size=3, stride=2, padding=0
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)
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def forward(self, x: Tensor):
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pad = (0, 1, 0, 1)
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x = nn.functional.pad(x, pad, mode="constant", value=0)
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x = self.conv(x)
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return x
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class Upsample(nn.Module):
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def __init__(self, in_channels: int):
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super().__init__()
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self.conv = nn.Conv2d(
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in_channels, in_channels, kernel_size=3, stride=1, padding=1
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)
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def forward(self, x: Tensor):
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x = nn.functional.interpolate(x, scale_factor=2.0, mode="nearest")
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x = self.conv(x)
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return x
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class Encoder(nn.Module):
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def __init__(
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self,
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resolution: int,
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in_channels: int,
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ch: int,
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ch_mult: list[int],
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num_res_blocks: int,
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z_channels: int,
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):
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super().__init__()
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self.quant_conv = torch.nn.Conv2d(2 * z_channels, 2 * z_channels, 1)
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self.ch = ch
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self.num_resolutions = len(ch_mult)
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self.num_res_blocks = num_res_blocks
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self.resolution = resolution
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self.in_channels = in_channels
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# downsampling
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self.conv_in = nn.Conv2d(
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in_channels, self.ch, kernel_size=3, stride=1, padding=1
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)
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curr_res = resolution
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in_ch_mult = (1,) + tuple(ch_mult)
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self.in_ch_mult = in_ch_mult
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self.down = nn.ModuleList()
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block_in = self.ch
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for i_level in range(self.num_resolutions):
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block = nn.ModuleList()
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attn = nn.ModuleList()
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block_in = ch * in_ch_mult[i_level]
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block_out = ch * ch_mult[i_level]
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for _ in range(self.num_res_blocks):
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block.append(ResnetBlock(in_channels=block_in, out_channels=block_out))
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block_in = block_out
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down = nn.Module()
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down.block = block
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down.attn = attn
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if i_level != self.num_resolutions - 1:
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down.downsample = Downsample(block_in)
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curr_res = curr_res // 2
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self.down.append(down)
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# middle
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self.mid = nn.Module()
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self.mid.block_1 = ResnetBlock(in_channels=block_in, out_channels=block_in)
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self.mid.attn_1 = AttnBlock(block_in)
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self.mid.block_2 = ResnetBlock(in_channels=block_in, out_channels=block_in)
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# end
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self.norm_out = nn.GroupNorm(
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num_groups=32, num_channels=block_in, eps=1e-6, affine=True
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)
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self.conv_out = nn.Conv2d(
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block_in, 2 * z_channels, kernel_size=3, stride=1, padding=1
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)
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self.gradient_checkpointing = False
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def enable_gradient_checkpointing(self):
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self.gradient_checkpointing = True
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def forward(self, x: Tensor) -> Tensor:
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# downsampling
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hs = [self.conv_in(x)]
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for i_level in range(self.num_resolutions):
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for i_block in range(self.num_res_blocks):
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if torch.is_grad_enabled() and self.gradient_checkpointing:
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h = ckpt.checkpoint(self.down[i_level].block[i_block], hs[-1])
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if len(self.down[i_level].attn) > 0:
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h = ckpt.checkpoint(self.down[i_level].attn[i_block], h)
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else:
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h = self.down[i_level].block[i_block](hs[-1])
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if len(self.down[i_level].attn) > 0:
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h = self.down[i_level].attn[i_block](h)
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hs.append(h)
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if i_level != self.num_resolutions - 1:
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if torch.is_grad_enabled() and self.gradient_checkpointing:
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hs.append(ckpt.checkpoint(self.down[i_level].downsample, hs[-1]))
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else:
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hs.append(self.down[i_level].downsample(hs[-1]))
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# middle
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h = hs[-1]
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if torch.is_grad_enabled() and self.gradient_checkpointing:
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h = ckpt.checkpoint(self.mid.block_1, h)
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h = ckpt.checkpoint(self.mid.attn_1, h)
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h = ckpt.checkpoint(self.mid.block_2, h)
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else:
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h = self.mid.block_1(h)
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h = self.mid.attn_1(h)
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h = self.mid.block_2(h)
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# end
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h = self.norm_out(h)
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h = swish(h)
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h = self.conv_out(h)
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h = self.quant_conv(h)
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return h
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class Decoder(nn.Module):
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def __init__(
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self,
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ch: int,
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out_ch: int,
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ch_mult: list[int],
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num_res_blocks: int,
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in_channels: int,
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resolution: int,
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z_channels: int,
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):
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super().__init__()
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self.post_quant_conv = torch.nn.Conv2d(z_channels, z_channels, 1)
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self.ch = ch
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self.num_resolutions = len(ch_mult)
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self.num_res_blocks = num_res_blocks
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self.resolution = resolution
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self.in_channels = in_channels
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self.ffactor = 2 ** (self.num_resolutions - 1)
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# compute in_ch_mult, block_in and curr_res at lowest res
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block_in = ch * ch_mult[self.num_resolutions - 1]
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curr_res = resolution // 2 ** (self.num_resolutions - 1)
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self.z_shape = (1, z_channels, curr_res, curr_res)
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# z to block_in
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self.conv_in = nn.Conv2d(
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z_channels, block_in, kernel_size=3, stride=1, padding=1
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)
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# middle
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self.mid = nn.Module()
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self.mid.block_1 = ResnetBlock(in_channels=block_in, out_channels=block_in)
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self.mid.attn_1 = AttnBlock(block_in)
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self.mid.block_2 = ResnetBlock(in_channels=block_in, out_channels=block_in)
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# upsampling
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self.up = nn.ModuleList()
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for i_level in reversed(range(self.num_resolutions)):
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block = nn.ModuleList()
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attn = nn.ModuleList()
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block_out = ch * ch_mult[i_level]
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for _ in range(self.num_res_blocks + 1):
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block.append(ResnetBlock(in_channels=block_in, out_channels=block_out))
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block_in = block_out
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up = nn.Module()
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up.block = block
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up.attn = attn
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if i_level != 0:
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up.upsample = Upsample(block_in)
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curr_res = curr_res * 2
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self.up.insert(0, up) # prepend to get consistent order
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# end
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self.norm_out = nn.GroupNorm(
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num_groups=32, num_channels=block_in, eps=1e-6, affine=True
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)
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self.conv_out = nn.Conv2d(block_in, out_ch, kernel_size=3, stride=1, padding=1)
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self.gradient_checkpointing = False
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def enable_gradient_checkpointing(self):
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self.gradient_checkpointing = True
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def forward(self, z: Tensor) -> Tensor:
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z = self.post_quant_conv(z)
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# get dtype for proper tracing
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upscale_dtype = next(self.up.parameters()).dtype
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# z to block_in
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h = self.conv_in(z)
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# middle
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if torch.is_grad_enabled() and self.gradient_checkpointing:
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h = ckpt.checkpoint(self.mid.block_1, h)
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h = ckpt.checkpoint(self.mid.attn_1, h)
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h = ckpt.checkpoint(self.mid.block_2, h)
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else:
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h = self.mid.block_1(h)
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h = self.mid.attn_1(h)
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h = self.mid.block_2(h)
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# cast to proper dtype
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h = h.to(upscale_dtype)
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# upsampling
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for i_level in reversed(range(self.num_resolutions)):
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for i_block in range(self.num_res_blocks + 1):
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if torch.is_grad_enabled() and self.gradient_checkpointing:
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h = ckpt.checkpoint(self.up[i_level].block[i_block], h)
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if len(self.up[i_level].attn) > 0:
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h = ckpt.checkpoint(self.up[i_level].attn[i_block], h)
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else:
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h = self.up[i_level].block[i_block](h)
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if len(self.up[i_level].attn) > 0:
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h = self.up[i_level].attn[i_block](h)
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if i_level != 0:
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if torch.is_grad_enabled() and self.gradient_checkpointing:
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h = ckpt.checkpoint(self.up[i_level].upsample, h)
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else:
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h = self.up[i_level].upsample(h)
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# end
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h = self.norm_out(h)
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h = swish(h)
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h = self.conv_out(h)
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return h
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class AutoEncoder(nn.Module, OstrisModelMixin):
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@classmethod
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def aitk_config_from_state_dict(cls, state_dict):
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# small decoder builds report 96ch at the first decoder block
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if state_dict["decoder.up.0.block.0.conv1.bias"].shape[0] == 96:
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return AutoEncoderSmallDecoderParams()
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return AutoEncoderParams()
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def __init__(self, params: AutoEncoderParams):
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super().__init__()
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self.params = params
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self.encoder = Encoder(
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resolution=params.resolution,
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in_channels=params.in_channels,
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ch=params.ch,
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ch_mult=params.ch_mult,
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num_res_blocks=params.num_res_blocks,
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z_channels=params.z_channels,
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)
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decoder_ch = params.ch
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if hasattr(params, "ch_encoder"):
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decoder_ch = params.ch_encoder
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self.decoder = Decoder(
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resolution=params.resolution,
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in_channels=params.in_channels,
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ch=decoder_ch,
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out_ch=params.out_ch,
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ch_mult=params.ch_mult,
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num_res_blocks=params.num_res_blocks,
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z_channels=params.z_channels,
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)
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self.bn_eps = 1e-4
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self.bn_momentum = 0.1
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self.ps = [2, 2]
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self.bn = torch.nn.BatchNorm2d(
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math.prod(self.ps) * params.z_channels,
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eps=self.bn_eps,
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momentum=self.bn_momentum,
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affine=False,
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track_running_stats=True,
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)
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self._gradient_checkpointing = False
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@property
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def gradient_checkpointing(self):
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return self._gradient_checkpointing
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@gradient_checkpointing.setter
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def gradient_checkpointing(self, value: bool):
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self._gradient_checkpointing = value
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self.encoder.gradient_checkpointing = value
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self.decoder.gradient_checkpointing = value
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@property
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def device(self):
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return next(self.parameters()).device
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@property
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def dtype(self):
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return next(self.parameters()).dtype
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def enable_gradient_checkpointing(self):
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self.gradient_checkpointing = True
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self.encoder.enable_gradient_checkpointing()
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self.decoder.enable_gradient_checkpointing()
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def normalize(self, z):
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self.bn.eval()
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return self.bn(z)
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def inv_normalize(self, z):
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self.bn.eval()
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s = torch.sqrt(self.bn.running_var.view(1, -1, 1, 1) + self.bn_eps)
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m = self.bn.running_mean.view(1, -1, 1, 1)
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return z * s + m
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def encode(self, x: Tensor) -> Tensor:
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moments = self.encoder(x)
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mean = torch.chunk(moments, 2, dim=1)[0]
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z = rearrange(
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mean,
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"... c (i pi) (j pj) -> ... (c pi pj) i j",
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pi=self.ps[0],
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pj=self.ps[1],
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)
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z = self.normalize(z)
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return z
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def decode(self, z: Tensor) -> Tensor:
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z = self.inv_normalize(z)
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z = rearrange(
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z,
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"... (c pi pj) i j -> ... c (i pi) (j pj)",
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pi=self.ps[0],
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pj=self.ps[1],
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)
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dec = self.decoder(z)
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return dec
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_NUM_RESOLUTIONS = 4
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def convert_diffusers_state_dict(src: dict[str, Tensor]) -> dict[str, Tensor]:
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out: dict[str, Tensor] = {}
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attn_substrings = (".mid.attn_1.",)
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for src_key, tensor in src.items():
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dst_key = _rewrite_diffusers_key(src_key)
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if dst_key is None:
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raise KeyError(f"Unrecognized diffusers VAE state-dict key: {src_key}")
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if (
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any(s in dst_key for s in attn_substrings)
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and dst_key.endswith(".weight")
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and tensor.ndim == 2
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):
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tensor = tensor.unsqueeze(-1).unsqueeze(-1)
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out[dst_key] = tensor
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return out
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def _rewrite_diffusers_key(key: str) -> str | None:
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if key.startswith("bn."):
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return key
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|
if key.startswith("quant_conv."):
|
|
return key.replace("quant_conv.", "encoder.quant_conv.", 1)
|
|
if key.startswith("post_quant_conv."):
|
|
return key.replace("post_quant_conv.", "decoder.post_quant_conv.", 1)
|
|
|
|
if key == "encoder.conv_norm_out.weight":
|
|
return "encoder.norm_out.weight"
|
|
if key == "encoder.conv_norm_out.bias":
|
|
return "encoder.norm_out.bias"
|
|
if key == "decoder.conv_norm_out.weight":
|
|
return "decoder.norm_out.weight"
|
|
if key == "decoder.conv_norm_out.bias":
|
|
return "decoder.norm_out.bias"
|
|
|
|
m = re.match(r"^(encoder|decoder)\.mid_block\.resnets\.(\d+)\.(.+)$", key)
|
|
if m:
|
|
side, idx, rest = m.group(1), int(m.group(2)), m.group(3)
|
|
rest = rest.replace("conv_shortcut", "nin_shortcut")
|
|
return f"{side}.mid.block_{idx + 1}.{rest}"
|
|
m = re.match(r"^(encoder|decoder)\.mid_block\.attentions\.0\.(.+)$", key)
|
|
if m:
|
|
side, rest = m.group(1), m.group(2)
|
|
rest = (
|
|
rest.replace("group_norm.", "norm.")
|
|
.replace("to_q.", "q.")
|
|
.replace("to_k.", "k.")
|
|
.replace("to_v.", "v.")
|
|
.replace("to_out.0.", "proj_out.")
|
|
)
|
|
return f"{side}.mid.attn_1.{rest}"
|
|
|
|
m = re.match(r"^encoder\.down_blocks\.(\d+)\.resnets\.(\d+)\.(.+)$", key)
|
|
if m:
|
|
level, res_idx, rest = m.group(1), m.group(2), m.group(3)
|
|
rest = rest.replace("conv_shortcut", "nin_shortcut")
|
|
return f"encoder.down.{level}.block.{res_idx}.{rest}"
|
|
m = re.match(r"^encoder\.down_blocks\.(\d+)\.downsamplers\.0\.conv\.(.+)$", key)
|
|
if m:
|
|
return f"encoder.down.{m.group(1)}.downsample.conv.{m.group(2)}"
|
|
|
|
m = re.match(r"^decoder\.up_blocks\.(\d+)\.resnets\.(\d+)\.(.+)$", key)
|
|
if m:
|
|
diffusers_idx = int(m.group(1))
|
|
res_idx = m.group(2)
|
|
rest = m.group(3).replace("conv_shortcut", "nin_shortcut")
|
|
return (
|
|
f"decoder.up.{_NUM_RESOLUTIONS - 1 - diffusers_idx}.block.{res_idx}.{rest}"
|
|
)
|
|
m = re.match(r"^decoder\.up_blocks\.(\d+)\.upsamplers\.0\.conv\.(.+)$", key)
|
|
if m:
|
|
diffusers_idx = int(m.group(1))
|
|
return f"decoder.up.{_NUM_RESOLUTIONS - 1 - diffusers_idx}.upsample.conv.{m.group(2)}"
|
|
|
|
if key.startswith(
|
|
(
|
|
"encoder.conv_in.",
|
|
"encoder.conv_out.",
|
|
"decoder.conv_in.",
|
|
"decoder.conv_out.",
|
|
)
|
|
):
|
|
return key
|
|
|
|
return None
|