import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
class VectorQuantizer(nn.Module):
"""
see https://github.com/MishaLaskin/vqvae/blob/d761a999e2267766400dc646d82d3ac3657771d4/models/quantizer.py
____________________________________________
Discretization bottleneck part of the VQ-VAE.
Inputs:
- n_e : number of embeddings
- e_dim : dimension of embedding
- beta : commitment cost used in loss term, beta * ||z_e(x)-sg[e]||^2
_____________________________________________
"""
def __init__(self, n_e, e_dim, beta):
super(VectorQuantizer, self).__init__()
self.n_e = n_e
self.e_dim = e_dim
self.beta = beta
self.embedding = nn.Embedding(self.n_e, self.e_dim)
self.embedding.weight.data.uniform_(-1.0 / self.n_e, 1.0 / self.n_e)
def forward(self, z):
"""
Inputs the output of the encoder network z and maps it to a discrete
one-hot vector that is the index of the closest embedding vector e_j
z (continuous) -> z_q (discrete)
z.shape = (batch, channel, height, width)
quantization pipeline:
1. get encoder input (B,C,H,W)
2. flatten input to (B*H*W,C)
"""
# reshape z -> (batch, height, width, channel) and flatten
z = z.permute(0, 2, 3, 1).contiguous()
z_flattened = z.view(-1, self.e_dim)
# distances from z to embeddings e_j (z - e)^2 = z^2 + e^2 - 2 e * z
d = torch.sum(z_flattened ** 2, dim=1, keepdim=True) + \
torch.sum(self.embedding.weight**2, dim=1) - 2 * \
torch.matmul(z_flattened, self.embedding.weight.t())
## could possible replace this here
# #\start...
# find closest encodings
min_value, min_encoding_indices = torch.min(d, dim=1)
min_encoding_indices = min_encoding_indices.unsqueeze(1)
min_encodings = torch.zeros(
min_encoding_indices.shape[0], self.n_e).to(z)
min_encodings.scatter_(1, min_encoding_indices, 1)
# dtype min encodings: torch.float32
# min_encodings shape: torch.Size([2048, 512])
# min_encoding_indices.shape: torch.Size([2048, 1])
# get quantized latent vectors
z_q = torch.matmul(min_encodings, self.embedding.weight).view(z.shape)
#.........\end
# with:
# .........\start
#min_encoding_indices = torch.argmin(d, dim=1)
#z_q = self.embedding(min_encoding_indices)
# ......\end......... (TODO)
# compute loss for embedding
loss = torch.mean((z_q.detach()-z)**2) + self.beta * \
torch.mean((z_q - z.detach()) ** 2)
# preserve gradients
z_q = z + (z_q - z).detach()
# perplexity
e_mean = torch.mean(min_encodings, dim=0)
perplexity = torch.exp(-torch.sum(e_mean * torch.log(e_mean + 1e-10)))
# reshape back to match original input shape
z_q = z_q.permute(0, 3, 1, 2).contiguous()
return z_q, loss, (perplexity, min_encodings, min_encoding_indices, d)
def get_codebook_entry(self, indices, shape):
# shape specifying (batch, height, width, channel)
# TODO: check for more easy handling with nn.Embedding
min_encodings = torch.zeros(indices.shape[0], self.n_e).to(indices)
min_encodings.scatter_(1, indices[:,None], 1)
# get quantized latent vectors
z_q = torch.matmul(min_encodings.float(), self.embedding.weight)
if shape is not None:
z_q = z_q.view(shape)
# reshape back to match original input shape
z_q = z_q.permute(0, 3, 1, 2).contiguous()
return z_q
# pytorch_diffusion + derived encoder decoder
def nonlinearity(x):
# swish
return x*torch.sigmoid(x)
def Normalize(in_channels):
return torch.nn.GroupNorm(num_groups=32, num_channels=in_channels, eps=1e-6, affine=True)
class Upsample(nn.Module):
def __init__(self, in_channels, with_conv):
super().__init__()
self.with_conv = with_conv
if self.with_conv:
self.conv = torch.nn.Conv2d(in_channels,
in_channels,
kernel_size=3,
stride=1,
padding=1)
def forward(self, x):
x = torch.nn.functional.interpolate(x, scale_factor=2.0, mode="nearest")
if self.with_conv:
x = self.conv(x)
return x
class Downsample(nn.Module):
def __init__(self, in_channels, with_conv):
super().__init__()
self.with_conv = with_conv
if self.with_conv:
# no asymmetric padding in torch conv, must do it ourselves
self.conv = torch.nn.Conv2d(in_channels,
in_channels,
kernel_size=3,
stride=2,
padding=0)
def forward(self, x):
if self.with_conv:
pad = (0,1,0,1)
x = torch.nn.functional.pad(x, pad, mode="constant", value=0)
x = self.conv(x)
else:
x = torch.nn.functional.avg_pool2d(x, kernel_size=2, stride=2)
return x
class ResnetBlock(nn.Module):
def __init__(self, *, in_channels, out_channels=None, conv_shortcut=False,
dropout, temb_channels=512):
super().__init__()
self.in_channels = in_channels
out_channels = in_channels if out_channels is None else out_channels
self.out_channels = out_channels
self.use_conv_shortcut = conv_shortcut
self.norm1 = Normalize(in_channels)
self.conv1 = torch.nn.Conv2d(in_channels,
out_channels,
kernel_size=3,
stride=1,
padding=1)
if temb_channels > 0:
self.temb_proj = torch.nn.Linear(temb_channels,
out_channels)
self.norm2 = Normalize(out_channels)
self.dropout = torch.nn.Dropout(dropout)
self.conv2 = torch.nn.Conv2d(out_channels,
out_channels,
kernel_size=3,
stride=1,
padding=1)
if self.in_channels != self.out_channels:
if self.use_conv_shortcut:
self.conv_shortcut = torch.nn.Conv2d(in_channels,
out_channels,
kernel_size=3,
stride=1,
padding=1)
else:
self.nin_shortcut = torch.nn.Conv2d(in_channels,
out_channels,
kernel_size=1,
stride=1,
padding=0)
def forward(self, x, temb):
h = x
h = self.norm1(h)
h = nonlinearity(h)
h = self.conv1(h)
if temb is not None:
h = h + self.temb_proj(nonlinearity(temb))[:,:,None,None]
h = self.norm2(h)
h = nonlinearity(h)
h = self.dropout(h)
h = self.conv2(h)
if self.in_channels != self.out_channels:
if self.use_conv_shortcut:
x = self.conv_shortcut(x)
else:
x = self.nin_shortcut(x)
return x+h
class MultiHeadAttnBlock(nn.Module):
def __init__(self, in_channels, head_size=1):
super().__init__()
self.in_channels = in_channels
self.head_size = head_size
self.att_size = in_channels // head_size
assert(in_channels % head_size == 0), 'The size of head should be divided by the number of channels.'
self.norm1 = Normalize(in_channels)
self.norm2 = Normalize(in_channels)
self.q = torch.nn.Conv2d(in_channels,
in_channels,
kernel_size=1,
stride=1,
padding=0)
self.k = torch.nn.Conv2d(in_channels,
in_channels,
kernel_size=1,
stride=1,
padding=0)
self.v = torch.nn.Conv2d(in_channels,
in_channels,
kernel_size=1,
stride=1,
padding=0)
self.proj_out = torch.nn.Conv2d(in_channels,
in_channels,
kernel_size=1,
stride=1,
padding=0)
self.num = 0
def forward(self, x, y=None):
h_ = x
h_ = self.norm1(h_)
if y is None:
y = h_
else:
y = self.norm2(y)
q = self.q(y)
k = self.k(h_)
v = self.v(h_)
# compute attention
b,c,h,w = q.shape
q = q.reshape(b, self.head_size, self.att_size ,h*w)
q = q.permute(0, 3, 1, 2) # b, hw, head, att
k = k.reshape(b, self.head_size, self.att_size ,h*w)
k = k.permute(0, 3, 1, 2)
v = v.reshape(b, self.head_size, self.att_size ,h*w)
v = v.permute(0, 3, 1, 2)
q = q.transpose(1, 2)
v = v.transpose(1, 2)
k = k.transpose(1, 2).transpose(2,3)
scale = int(self.att_size)**(-0.5)
q.mul_(scale)
w_ = torch.matmul(q, k)
w_ = F.softmax(w_, dim=3)
w_ = w_.matmul(v)
w_ = w_.transpose(1, 2).contiguous() # [b, h*w, head, att]
w_ = w_.view(b, h, w, -1)
w_ = w_.permute(0, 3, 1, 2)
w_ = self.proj_out(w_)
return x+w_
class MultiHeadEncoder(nn.Module):
def __init__(self, ch, out_ch, ch_mult=(1,2,4,8), num_res_blocks=2,
attn_resolutions=[16], dropout=0.0, resamp_with_conv=True, in_channels=3,
resolution=512, z_channels=256, double_z=True, enable_mid=True,
head_size=1, **ignore_kwargs):
super().__init__()
self.ch = ch
self.temb_ch = 0
self.num_resolutions = len(ch_mult)
self.num_res_blocks = num_res_blocks
self.resolution = resolution
self.in_channels = in_channels
self.enable_mid = enable_mid
# downsampling
self.conv_in = torch.nn.Conv2d(in_channels,
self.ch,
kernel_size=3,
stride=1,
padding=1)
curr_res = resolution
in_ch_mult = (1,)+tuple(ch_mult)
self.down = nn.ModuleList()
for i_level in range(self.num_resolutions):
block = nn.ModuleList()
attn = nn.ModuleList()
block_in = ch*in_ch_mult[i_level]
block_out = ch*ch_mult[i_level]
for i_block in range(self.num_res_blocks):
block.append(ResnetBlock(in_channels=block_in,
out_channels=block_out,
temb_channels=self.temb_ch,
dropout=dropout))
block_in = block_out
if curr_res in attn_resolutions:
attn.append(MultiHeadAttnBlock(block_in, head_size))
down = nn.Module()
down.block = block
down.attn = attn
if i_level != self.num_resolutions-1:
down.downsample = Downsample(block_in, resamp_with_conv)
curr_res = curr_res // 2
self.down.append(down)
# middle
if self.enable_mid:
self.mid = nn.Module()
self.mid.block_1 = ResnetBlock(in_channels=block_in,
out_channels=block_in,
temb_channels=self.temb_ch,
dropout=dropout)
self.mid.attn_1 = MultiHeadAttnBlock(block_in, head_size)
self.mid.block_2 = ResnetBlock(in_channels=block_in,
out_channels=block_in,
temb_channels=self.temb_ch,
dropout=dropout)
# end
self.norm_out = Normalize(block_in)
self.conv_out = torch.nn.Conv2d(block_in,
2*z_channels if double_z else z_channels,
kernel_size=3,
stride=1,
padding=1)
def forward(self, x):
#assert x.shape[2] == x.shape[3] == self.resolution, "{}, {}, {}".format(x.shape[2], x.shape[3], self.resolution)
hs = {}
# timestep embedding
temb = None
# downsampling
h = self.conv_in(x)
hs['in'] = h
for i_level in range(self.num_resolutions):
for i_block in range(self.num_res_blocks):
h = self.down[i_level].block[i_block](h, temb)
if len(self.down[i_level].attn) > 0:
h = self.down[i_level].attn[i_block](h)
if i_level != self.num_resolutions-1:
# hs.append(h)
hs['block_'+str(i_level)] = h
h = self.down[i_level].downsample(h)
# middle
# h = hs[-1]
if self.enable_mid:
h = self.mid.block_1(h, temb)
hs['block_'+str(i_level)+'_atten'] = h
h = self.mid.attn_1(h)
h = self.mid.block_2(h, temb)
hs['mid_atten'] = h
# end
h = self.norm_out(h)
h = nonlinearity(h)
h = self.conv_out(h)
# hs.append(h)
hs['out'] = h
return hs
class MultiHeadDecoder(nn.Module):
def __init__(self, ch, out_ch, ch_mult=(1,2,4,8), num_res_blocks=2,
attn_resolutions=16, dropout=0.0, resamp_with_conv=True, in_channels=3,
resolution=512, z_channels=256, give_pre_end=False, enable_mid=True,
head_size=1, **ignorekwargs):
super().__init__()
self.ch = ch
self.temb_ch = 0
self.num_resolutions = len(ch_mult)
self.num_res_blocks = num_res_blocks
self.resolution = resolution
self.in_channels = in_channels
self.give_pre_end = give_pre_end
self.enable_mid = enable_mid
# compute in_ch_mult, block_in and curr_res at lowest res
in_ch_mult = (1,)+tuple(ch_mult)
block_in = ch*ch_mult[self.num_resolutions-1]
curr_res = resolution // 2**(self.num_resolutions-1)
self.z_shape = (1,z_channels,curr_res,curr_res)
print("Working with z of shape {} = {} dimensions.".format(
self.z_shape, np.prod(self.z_shape)))
# z to block_in
self.conv_in = torch.nn.Conv2d(z_channels,
block_in,
kernel_size=3,
stride=1,
padding=1)
# middle
if self.enable_mid:
self.mid = nn.Module()
self.mid.block_1 = ResnetBlock(in_channels=block_in,
out_channels=block_in,
temb_channels=self.temb_ch,
dropout=dropout)
self.mid.attn_1 = MultiHeadAttnBlock(block_in, head_size)
self.mid.block_2 = ResnetBlock(in_channels=block_in,
out_channels=block_in,
temb_channels=self.temb_ch,
dropout=dropout)
# upsampling
self.up = nn.ModuleList()
for i_level in reversed(range(self.num_resolutions)):
block = nn.ModuleList()
attn = nn.ModuleList()
block_out = ch*ch_mult[i_level]
for i_block in range(self.num_res_blocks+1):
block.append(ResnetBlock(in_channels=block_in,
out_channels=block_out,
temb_channels=self.temb_ch,
dropout=dropout))
block_in = block_out
if curr_res in attn_resolutions:
attn.append(MultiHeadAttnBlock(block_in, head_size))
up = nn.Module()
up.block = block
up.attn = attn
if i_level != 0:
up.upsample = Upsample(block_in, resamp_with_conv)
curr_res = curr_res * 2
self.up.insert(0, up) # prepend to get consistent order
# end
self.norm_out = Normalize(block_in)
self.conv_out = torch.nn.Conv2d(block_in,
out_ch,
kernel_size=3,
stride=1,
padding=1)
def forward(self, z):
#assert z.shape[1:] == self.z_shape[1:]
self.last_z_shape = z.shape
# timestep embedding
temb = None
# z to block_in
h = self.conv_in(z)
# middle
if self.enable_mid:
h = self.mid.block_1(h, temb)
h = self.mid.attn_1(h)
h = self.mid.block_2(h, temb)
# upsampling
for i_level in reversed(range(self.num_resolutions)):
for i_block in range(self.num_res_blocks+1):
h = self.up[i_level].block[i_block](h, temb)
if len(self.up[i_level].attn) > 0:
h = self.up[i_level].attn[i_block](h)
if i_level != 0:
h = self.up[i_level].upsample(h)
# end
if self.give_pre_end:
return h
h = self.norm_out(h)
h = nonlinearity(h)
h = self.conv_out(h)
return h
class MultiHeadDecoderTransformer(nn.Module):
def __init__(self, ch, out_ch, ch_mult=(1,2,4,8), num_res_blocks=2,
attn_resolutions=16, dropout=0.0, resamp_with_conv=True, in_channels=3,
resolution=512, z_channels=256, give_pre_end=False, enable_mid=True,
head_size=1, **ignorekwargs):
super().__init__()
self.ch = ch
self.temb_ch = 0
self.num_resolutions = len(ch_mult)
self.num_res_blocks = num_res_blocks
self.resolution = resolution
self.in_channels = in_channels
self.give_pre_end = give_pre_end
self.enable_mid = enable_mid
# compute in_ch_mult, block_in and curr_res at lowest res
in_ch_mult = (1,)+tuple(ch_mult)
block_in = ch*ch_mult[self.num_resolutions-1]
curr_res = resolution // 2**(self.num_resolutions-1)
self.z_shape = (1,z_channels,curr_res,curr_res)
print("Working with z of shape {} = {} dimensions.".format(
self.z_shape, np.prod(self.z_shape)))
# z to block_in
self.conv_in = torch.nn.Conv2d(z_channels,
block_in,
kernel_size=3,
stride=1,
padding=1)
# middle
if self.enable_mid:
self.mid = nn.Module()
self.mid.block_1 = ResnetBlock(in_channels=block_in,
out_channels=block_in,
temb_channels=self.temb_ch,
dropout=dropout)
self.mid.attn_1 = MultiHeadAttnBlock(block_in, head_size)
self.mid.block_2 = ResnetBlock(in_channels=block_in,
out_channels=block_in,
temb_channels=self.temb_ch,
dropout=dropout)
# upsampling
self.up = nn.ModuleList()
for i_level in reversed(range(self.num_resolutions)):
block = nn.ModuleList()
attn = nn.ModuleList()
block_out = ch*ch_mult[i_level]
for i_block in range(self.num_res_blocks+1):
block.append(ResnetBlock(in_channels=block_in,
out_channels=block_out,
temb_channels=self.temb_ch,
dropout=dropout))
block_in = block_out
if curr_res in attn_resolutions:
attn.append(MultiHeadAttnBlock(block_in, head_size))
up = nn.Module()
up.block = block
up.attn = attn
if i_level != 0:
up.upsample = Upsample(block_in, resamp_with_conv)
curr_res = curr_res * 2
self.up.insert(0, up) # prepend to get consistent order
# end
self.norm_out = Normalize(block_in)
self.conv_out = torch.nn.Conv2d(block_in,
out_ch,
kernel_size=3,
stride=1,
padding=1)
def forward(self, z, hs):
#assert z.shape[1:] == self.z_shape[1:]
# self.last_z_shape = z.shape
# timestep embedding
temb = None
# z to block_in
h = self.conv_in(z)
# middle
if self.enable_mid:
h = self.mid.block_1(h, temb)
h = self.mid.attn_1(h, hs['mid_atten'])
h = self.mid.block_2(h, temb)
# upsampling
for i_level in reversed(range(self.num_resolutions)):
for i_block in range(self.num_res_blocks+1):
h = self.up[i_level].block[i_block](h, temb)
if len(self.up[i_level].attn) > 0:
if 'block_'+str(i_level)+'_atten' in hs:
h = self.up[i_level].attn[i_block](h, hs['block_'+str(i_level)+'_atten'])
else:
h = self.up[i_level].attn[i_block](h, hs['block_'+str(i_level)])
if i_level != 0:
h = self.up[i_level].upsample(h)
# end
if self.give_pre_end:
return h
h = self.norm_out(h)
h = nonlinearity(h)
h = self.conv_out(h)
return h
class VQVAEGAN(nn.Module):
def __init__(self, n_embed=1024, embed_dim=256, ch=128, out_ch=3, ch_mult=(1,2,4,8),
num_res_blocks=2, attn_resolutions=16, dropout=0.0, in_channels=3,
resolution=512, z_channels=256, double_z=False, enable_mid=True,
fix_decoder=False, fix_codebook=False, head_size=1, **ignore_kwargs):
super(VQVAEGAN, self).__init__()
self.encoder = MultiHeadEncoder(ch=ch, out_ch=out_ch, ch_mult=ch_mult, num_res_blocks=num_res_blocks,
attn_resolutions=attn_resolutions, dropout=dropout, in_channels=in_channels,
resolution=resolution, z_channels=z_channels, double_z=double_z,
enable_mid=enable_mid, head_size=head_size)
self.decoder = MultiHeadDecoder(ch=ch, out_ch=out_ch, ch_mult=ch_mult, num_res_blocks=num_res_blocks,
attn_resolutions=attn_resolutions, dropout=dropout, in_channels=in_channels,
resolution=resolution, z_channels=z_channels, enable_mid=enable_mid, head_size=head_size)
self.quantize = VectorQuantizer(n_embed, embed_dim, beta=0.25)
self.quant_conv = torch.nn.Conv2d(z_channels, embed_dim, 1)
self.post_quant_conv = torch.nn.Conv2d(embed_dim, z_channels, 1)
if fix_decoder:
for _, param in self.decoder.named_parameters():
param.requires_grad = False
for _, param in self.post_quant_conv.named_parameters():
param.requires_grad = False
for _, param in self.quantize.named_parameters():
param.requires_grad = False
elif fix_codebook:
for _, param in self.quantize.named_parameters():
param.requires_grad = False
def encode(self, x):
hs = self.encoder(x)
h = self.quant_conv(hs['out'])
quant, emb_loss, info = self.quantize(h)
return quant, emb_loss, info, hs
def decode(self, quant):
quant = self.post_quant_conv(quant)
dec = self.decoder(quant)
return dec
def forward(self, input):
quant, diff, info, hs = self.encode(input)
dec = self.decode(quant)
return dec, diff, info, hs
class VQVAEGANMultiHeadTransformer(nn.Module):
def __init__(self,
n_embed=1024,
embed_dim=256,
ch=64,
out_ch=3,
ch_mult=(1, 2, 2, 4, 4, 8),
num_res_blocks=2,
attn_resolutions=(16, ),
dropout=0.0,
in_channels=3,
resolution=512,
z_channels=256,
double_z=False,
enable_mid=True,
fix_decoder=False,
fix_codebook=True,
fix_encoder=False,
head_size=4,
ex_multi_scale_num=1):
super(VQVAEGANMultiHeadTransformer, self).__init__()
self.encoder = MultiHeadEncoder(ch=ch, out_ch=out_ch, ch_mult=ch_mult, num_res_blocks=num_res_blocks,
attn_resolutions=attn_resolutions, dropout=dropout, in_channels=in_channels,
resolution=resolution, z_channels=z_channels, double_z=double_z,
enable_mid=enable_mid, head_size=head_size)
for i in range(ex_multi_scale_num):
attn_resolutions = [attn_resolutions[0], attn_resolutions[-1]*2]
self.decoder = MultiHeadDecoderTransformer(ch=ch, out_ch=out_ch, ch_mult=ch_mult, num_res_blocks=num_res_blocks,
attn_resolutions=attn_resolutions, dropout=dropout, in_channels=in_channels,
resolution=resolution, z_channels=z_channels, enable_mid=enable_mid, head_size=head_size)
self.quantize = VectorQuantizer(n_embed, embed_dim, beta=0.25)
self.quant_conv = torch.nn.Conv2d(z_channels, embed_dim, 1)
self.post_quant_conv = torch.nn.Conv2d(embed_dim, z_channels, 1)
if fix_decoder:
for _, param in self.decoder.named_parameters():
param.requires_grad = False
for _, param in self.post_quant_conv.named_parameters():
param.requires_grad = False
for _, param in self.quantize.named_parameters():
param.requires_grad = False
elif fix_codebook:
for _, param in self.quantize.named_parameters():
param.requires_grad = False
if fix_encoder:
for _, param in self.encoder.named_parameters():
param.requires_grad = False
for _, param in self.quant_conv.named_parameters():
param.requires_grad = False
def encode(self, x):
hs = self.encoder(x)
h = self.quant_conv(hs['out'])
quant, emb_loss, info = self.quantize(h)
return quant, emb_loss, info, hs
def decode(self, quant, hs):
quant = self.post_quant_conv(quant)
dec = self.decoder(quant, hs)
return dec
def forward(self, input):
quant, diff, info, hs = self.encode(input)
dec = self.decode(quant, hs)
return dec, diff, info, hs