vumichien's picture
First commit
4275cae
raw
history blame
14.1 kB
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
class QuantizeEMAReset(nn.Module):
def __init__(self, nb_code, code_dim, args):
super().__init__()
self.nb_code = nb_code
self.code_dim = code_dim
self.mu = args.mu
self.reset_codebook()
def reset_codebook(self):
self.init = False
self.code_sum = None
self.code_count = None
if torch.cuda.is_available():
self.register_buffer('codebook', torch.zeros(self.nb_code, self.code_dim).cuda())
else:
self.register_buffer('codebook', torch.zeros(self.nb_code, self.code_dim))
def _tile(self, x):
nb_code_x, code_dim = x.shape
if nb_code_x < self.nb_code:
n_repeats = (self.nb_code + nb_code_x - 1) // nb_code_x
std = 0.01 / np.sqrt(code_dim)
out = x.repeat(n_repeats, 1)
out = out + torch.randn_like(out) * std
else :
out = x
return out
def init_codebook(self, x):
out = self._tile(x)
self.codebook = out[:self.nb_code]
self.code_sum = self.codebook.clone()
self.code_count = torch.ones(self.nb_code, device=self.codebook.device)
self.init = True
@torch.no_grad()
def compute_perplexity(self, code_idx) :
# Calculate new centres
code_onehot = torch.zeros(self.nb_code, code_idx.shape[0], device=code_idx.device) # nb_code, N * L
code_onehot.scatter_(0, code_idx.view(1, code_idx.shape[0]), 1)
code_count = code_onehot.sum(dim=-1) # nb_code
prob = code_count / torch.sum(code_count)
perplexity = torch.exp(-torch.sum(prob * torch.log(prob + 1e-7)))
return perplexity
@torch.no_grad()
def update_codebook(self, x, code_idx):
code_onehot = torch.zeros(self.nb_code, x.shape[0], device=x.device) # nb_code, N * L
code_onehot.scatter_(0, code_idx.view(1, x.shape[0]), 1)
code_sum = torch.matmul(code_onehot, x) # nb_code, w
code_count = code_onehot.sum(dim=-1) # nb_code
out = self._tile(x)
code_rand = out[:self.nb_code]
# Update centres
self.code_sum = self.mu * self.code_sum + (1. - self.mu) * code_sum # w, nb_code
self.code_count = self.mu * self.code_count + (1. - self.mu) * code_count # nb_code
usage = (self.code_count.view(self.nb_code, 1) >= 1.0).float()
code_update = self.code_sum.view(self.nb_code, self.code_dim) / self.code_count.view(self.nb_code, 1)
self.codebook = usage * code_update + (1 - usage) * code_rand
prob = code_count / torch.sum(code_count)
perplexity = torch.exp(-torch.sum(prob * torch.log(prob + 1e-7)))
return perplexity
def preprocess(self, x):
# NCT -> NTC -> [NT, C]
x = x.permute(0, 2, 1).contiguous()
x = x.view(-1, x.shape[-1])
return x
def quantize(self, x):
# Calculate latent code x_l
k_w = self.codebook.t()
distance = torch.sum(x ** 2, dim=-1, keepdim=True) - 2 * torch.matmul(x, k_w) + torch.sum(k_w ** 2, dim=0,
keepdim=True) # (N * L, b)
_, code_idx = torch.min(distance, dim=-1)
return code_idx
def dequantize(self, code_idx):
x = F.embedding(code_idx, self.codebook)
return x
def forward(self, x):
N, width, T = x.shape
# Preprocess
x = self.preprocess(x)
# Init codebook if not inited
if self.training and not self.init:
self.init_codebook(x)
# quantize and dequantize through bottleneck
code_idx = self.quantize(x)
x_d = self.dequantize(code_idx)
# Update embeddings
if self.training:
perplexity = self.update_codebook(x, code_idx)
else :
perplexity = self.compute_perplexity(code_idx)
# Loss
commit_loss = F.mse_loss(x, x_d.detach())
# Passthrough
x_d = x + (x_d - x).detach()
# Postprocess
x_d = x_d.view(N, T, -1).permute(0, 2, 1).contiguous() #(N, DIM, T)
return x_d, commit_loss, perplexity
class Quantizer(nn.Module):
def __init__(self, n_e, e_dim, beta):
super(Quantizer, self).__init__()
self.e_dim = e_dim
self.n_e = n_e
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):
N, width, T = z.shape
z = self.preprocess(z)
assert z.shape[-1] == self.e_dim
z_flattened = z.contiguous().view(-1, self.e_dim)
# B x V
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())
# B x 1
min_encoding_indices = torch.argmin(d, dim=1)
z_q = self.embedding(min_encoding_indices).view(z.shape)
# compute loss for embedding
loss = torch.mean((z_q - z.detach())**2) + self.beta * \
torch.mean((z_q.detach() - z)**2)
# preserve gradients
z_q = z + (z_q - z).detach()
z_q = z_q.view(N, T, -1).permute(0, 2, 1).contiguous() #(N, DIM, T)
min_encodings = F.one_hot(min_encoding_indices, self.n_e).type(z.dtype)
e_mean = torch.mean(min_encodings, dim=0)
perplexity = torch.exp(-torch.sum(e_mean*torch.log(e_mean + 1e-10)))
return z_q, loss, perplexity
def quantize(self, z):
assert z.shape[-1] == self.e_dim
# B x V
d = torch.sum(z ** 2, dim=1, keepdim=True) + \
torch.sum(self.embedding.weight ** 2, dim=1) - 2 * \
torch.matmul(z, self.embedding.weight.t())
# B x 1
min_encoding_indices = torch.argmin(d, dim=1)
return min_encoding_indices
def dequantize(self, indices):
index_flattened = indices.view(-1)
z_q = self.embedding(index_flattened)
z_q = z_q.view(indices.shape + (self.e_dim, )).contiguous()
return z_q
def preprocess(self, x):
# NCT -> NTC -> [NT, C]
x = x.permute(0, 2, 1).contiguous()
x = x.view(-1, x.shape[-1])
return x
class QuantizeReset(nn.Module):
def __init__(self, nb_code, code_dim, args):
super().__init__()
self.nb_code = nb_code
self.code_dim = code_dim
self.reset_codebook()
self.codebook = nn.Parameter(torch.randn(nb_code, code_dim))
def reset_codebook(self):
self.init = False
self.code_count = None
def _tile(self, x):
nb_code_x, code_dim = x.shape
if nb_code_x < self.nb_code:
n_repeats = (self.nb_code + nb_code_x - 1) // nb_code_x
std = 0.01 / np.sqrt(code_dim)
out = x.repeat(n_repeats, 1)
out = out + torch.randn_like(out) * std
else :
out = x
return out
def init_codebook(self, x):
out = self._tile(x)
self.codebook = nn.Parameter(out[:self.nb_code])
self.code_count = torch.ones(self.nb_code, device=self.codebook.device)
self.init = True
@torch.no_grad()
def compute_perplexity(self, code_idx) :
# Calculate new centres
code_onehot = torch.zeros(self.nb_code, code_idx.shape[0], device=code_idx.device) # nb_code, N * L
code_onehot.scatter_(0, code_idx.view(1, code_idx.shape[0]), 1)
code_count = code_onehot.sum(dim=-1) # nb_code
prob = code_count / torch.sum(code_count)
perplexity = torch.exp(-torch.sum(prob * torch.log(prob + 1e-7)))
return perplexity
def update_codebook(self, x, code_idx):
code_onehot = torch.zeros(self.nb_code, x.shape[0], device=x.device) # nb_code, N * L
code_onehot.scatter_(0, code_idx.view(1, x.shape[0]), 1)
code_count = code_onehot.sum(dim=-1) # nb_code
out = self._tile(x)
code_rand = out[:self.nb_code]
# Update centres
self.code_count = code_count # nb_code
usage = (self.code_count.view(self.nb_code, 1) >= 1.0).float()
self.codebook.data = usage * self.codebook.data + (1 - usage) * code_rand
prob = code_count / torch.sum(code_count)
perplexity = torch.exp(-torch.sum(prob * torch.log(prob + 1e-7)))
return perplexity
def preprocess(self, x):
# NCT -> NTC -> [NT, C]
x = x.permute(0, 2, 1).contiguous()
x = x.view(-1, x.shape[-1])
return x
def quantize(self, x):
# Calculate latent code x_l
k_w = self.codebook.t()
distance = torch.sum(x ** 2, dim=-1, keepdim=True) - 2 * torch.matmul(x, k_w) + torch.sum(k_w ** 2, dim=0,
keepdim=True) # (N * L, b)
_, code_idx = torch.min(distance, dim=-1)
return code_idx
def dequantize(self, code_idx):
x = F.embedding(code_idx, self.codebook)
return x
def forward(self, x):
N, width, T = x.shape
# Preprocess
x = self.preprocess(x)
# Init codebook if not inited
if self.training and not self.init:
self.init_codebook(x)
# quantize and dequantize through bottleneck
code_idx = self.quantize(x)
x_d = self.dequantize(code_idx)
# Update embeddings
if self.training:
perplexity = self.update_codebook(x, code_idx)
else :
perplexity = self.compute_perplexity(code_idx)
# Loss
commit_loss = F.mse_loss(x, x_d.detach())
# Passthrough
x_d = x + (x_d - x).detach()
# Postprocess
x_d = x_d.view(N, T, -1).permute(0, 2, 1).contiguous() #(N, DIM, T)
return x_d, commit_loss, perplexity
class QuantizeEMA(nn.Module):
def __init__(self, nb_code, code_dim, args):
super().__init__()
self.nb_code = nb_code
self.code_dim = code_dim
self.mu = 0.99
self.reset_codebook()
def reset_codebook(self):
self.init = False
self.code_sum = None
self.code_count = None
self.register_buffer('codebook', torch.zeros(self.nb_code, self.code_dim).cuda())
def _tile(self, x):
nb_code_x, code_dim = x.shape
if nb_code_x < self.nb_code:
n_repeats = (self.nb_code + nb_code_x - 1) // nb_code_x
std = 0.01 / np.sqrt(code_dim)
out = x.repeat(n_repeats, 1)
out = out + torch.randn_like(out) * std
else :
out = x
return out
def init_codebook(self, x):
out = self._tile(x)
self.codebook = out[:self.nb_code]
self.code_sum = self.codebook.clone()
self.code_count = torch.ones(self.nb_code, device=self.codebook.device)
self.init = True
@torch.no_grad()
def compute_perplexity(self, code_idx) :
# Calculate new centres
code_onehot = torch.zeros(self.nb_code, code_idx.shape[0], device=code_idx.device) # nb_code, N * L
code_onehot.scatter_(0, code_idx.view(1, code_idx.shape[0]), 1)
code_count = code_onehot.sum(dim=-1) # nb_code
prob = code_count / torch.sum(code_count)
perplexity = torch.exp(-torch.sum(prob * torch.log(prob + 1e-7)))
return perplexity
@torch.no_grad()
def update_codebook(self, x, code_idx):
code_onehot = torch.zeros(self.nb_code, x.shape[0], device=x.device) # nb_code, N * L
code_onehot.scatter_(0, code_idx.view(1, x.shape[0]), 1)
code_sum = torch.matmul(code_onehot, x) # nb_code, w
code_count = code_onehot.sum(dim=-1) # nb_code
# Update centres
self.code_sum = self.mu * self.code_sum + (1. - self.mu) * code_sum # w, nb_code
self.code_count = self.mu * self.code_count + (1. - self.mu) * code_count # nb_code
code_update = self.code_sum.view(self.nb_code, self.code_dim) / self.code_count.view(self.nb_code, 1)
self.codebook = code_update
prob = code_count / torch.sum(code_count)
perplexity = torch.exp(-torch.sum(prob * torch.log(prob + 1e-7)))
return perplexity
def preprocess(self, x):
# NCT -> NTC -> [NT, C]
x = x.permute(0, 2, 1).contiguous()
x = x.view(-1, x.shape[-1])
return x
def quantize(self, x):
# Calculate latent code x_l
k_w = self.codebook.t()
distance = torch.sum(x ** 2, dim=-1, keepdim=True) - 2 * torch.matmul(x, k_w) + torch.sum(k_w ** 2, dim=0,
keepdim=True) # (N * L, b)
_, code_idx = torch.min(distance, dim=-1)
return code_idx
def dequantize(self, code_idx):
x = F.embedding(code_idx, self.codebook)
return x
def forward(self, x):
N, width, T = x.shape
# Preprocess
x = self.preprocess(x)
# Init codebook if not inited
if self.training and not self.init:
self.init_codebook(x)
# quantize and dequantize through bottleneck
code_idx = self.quantize(x)
x_d = self.dequantize(code_idx)
# Update embeddings
if self.training:
perplexity = self.update_codebook(x, code_idx)
else :
perplexity = self.compute_perplexity(code_idx)
# Loss
commit_loss = F.mse_loss(x, x_d.detach())
# Passthrough
x_d = x + (x_d - x).detach()
# Postprocess
x_d = x_d.view(N, T, -1).permute(0, 2, 1).contiguous() #(N, DIM, T)
return x_d, commit_loss, perplexity