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import numpy as np
import torch
from dac.nn.quantize import ResidualVectorQuantize as DACResidualVQ
from einops import rearrange
from torch import nn
from torch.nn import functional as F
from vector_quantize_pytorch import FSQ, ResidualVQ
class Bottleneck(nn.Module):
def __init__(self, is_discrete: bool = False):
super().__init__()
self.is_discrete = is_discrete
def encode(self, x, return_info=False, **kwargs):
raise NotImplementedError
def decode(self, x):
raise NotImplementedError
class DiscreteBottleneck(Bottleneck):
def __init__(self, num_quantizers, codebook_size, tokens_id):
super().__init__(is_discrete=True)
self.num_quantizers = num_quantizers
self.codebook_size = codebook_size
self.tokens_id = tokens_id
def decode_tokens(self, codes, **kwargs):
raise NotImplementedError
class TanhBottleneck(Bottleneck):
def __init__(self):
super().__init__(is_discrete=False)
self.tanh = nn.Tanh()
def encode(self, x, return_info=False):
info = {}
x = torch.tanh(x)
if return_info:
return x, info
else:
return x
def decode(self, x):
return x
def vae_sample(mean, scale):
stdev = nn.functional.softplus(scale) + 1e-4
var = stdev * stdev
logvar = torch.log(var)
latents = torch.randn_like(mean) * stdev + mean
kl = (mean * mean + var - logvar - 1).sum(1).mean()
return latents, kl
class VAEBottleneck(Bottleneck):
def __init__(self):
super().__init__(is_discrete=False)
def encode(self, x, return_info=False, **kwargs):
info = {}
mean, scale = x.chunk(2, dim=1)
x, kl = vae_sample(mean, scale)
info["kl"] = kl
if return_info:
return x, info
else:
return x
def decode(self, x):
return x
def compute_mean_kernel(x, y):
kernel_input = (x[:, None] - y[None]).pow(2).mean(2) / x.shape[-1]
return torch.exp(-kernel_input).mean()
def compute_mmd(latents):
latents_reshaped = latents.permute(0, 2, 1).reshape(-1, latents.shape[1])
noise = torch.randn_like(latents_reshaped)
latents_kernel = compute_mean_kernel(latents_reshaped, latents_reshaped)
noise_kernel = compute_mean_kernel(noise, noise)
latents_noise_kernel = compute_mean_kernel(latents_reshaped, noise)
mmd = latents_kernel + noise_kernel - 2 * latents_noise_kernel
return mmd.mean()
class WassersteinBottleneck(Bottleneck):
def __init__(self, noise_augment_dim: int = 0, bypass_mmd: bool = False):
super().__init__(is_discrete=False)
self.noise_augment_dim = noise_augment_dim
self.bypass_mmd = bypass_mmd
def encode(self, x, return_info=False):
info = {}
if self.training and return_info:
if self.bypass_mmd:
mmd = torch.tensor(0.0)
else:
mmd = compute_mmd(x)
info["mmd"] = mmd
if return_info:
return x, info
return x
def decode(self, x):
if self.noise_augment_dim > 0:
noise = torch.randn(
x.shape[0], self.noise_augment_dim, x.shape[-1]
).type_as(x)
x = torch.cat([x, noise], dim=1)
return x
class L2Bottleneck(Bottleneck):
def __init__(self):
super().__init__(is_discrete=False)
def encode(self, x, return_info=False):
info = {}
x = F.normalize(x, dim=1)
if return_info:
return x, info
else:
return x
def decode(self, x):
return F.normalize(x, dim=1)
class RVQBottleneck(DiscreteBottleneck):
def __init__(self, **quantizer_kwargs):
super().__init__(
num_quantizers=quantizer_kwargs["num_quantizers"],
codebook_size=quantizer_kwargs["codebook_size"],
tokens_id="quantizer_indices",
)
self.quantizer = ResidualVQ(**quantizer_kwargs)
self.num_quantizers = quantizer_kwargs["num_quantizers"]
def encode(self, x, return_info=False, **kwargs):
info = {}
x = rearrange(x, "b c n -> b n c")
x, indices, loss = self.quantizer(x)
x = rearrange(x, "b n c -> b c n")
info["quantizer_indices"] = indices
info["quantizer_loss"] = loss.mean()
if return_info:
return x, info
else:
return x
def decode(self, x):
return x
def decode_tokens(self, codes, **kwargs):
latents = self.quantizer.get_outputs_from_indices(codes)
return self.decode(latents, **kwargs)
class RVQVAEBottleneck(DiscreteBottleneck):
def __init__(self, **quantizer_kwargs):
super().__init__(
num_quantizers=quantizer_kwargs["num_quantizers"],
codebook_size=quantizer_kwargs["codebook_size"],
tokens_id="quantizer_indices",
)
self.quantizer = ResidualVQ(**quantizer_kwargs)
self.num_quantizers = quantizer_kwargs["num_quantizers"]
def encode(self, x, return_info=False):
info = {}
x, kl = vae_sample(*x.chunk(2, dim=1))
info["kl"] = kl
x = rearrange(x, "b c n -> b n c")
x, indices, loss = self.quantizer(x)
x = rearrange(x, "b n c -> b c n")
info["quantizer_indices"] = indices
info["quantizer_loss"] = loss.mean()
if return_info:
return x, info
else:
return x
def decode(self, x):
return x
def decode_tokens(self, codes, **kwargs):
latents = self.quantizer.get_outputs_from_indices(codes)
return self.decode(latents, **kwargs)
class DACRVQBottleneck(DiscreteBottleneck):
def __init__(
self, quantize_on_decode=False, noise_augment_dim=0, **quantizer_kwargs
):
super().__init__(
num_quantizers=quantizer_kwargs["n_codebooks"],
codebook_size=quantizer_kwargs["codebook_size"],
tokens_id="codes",
)
self.quantizer = DACResidualVQ(**quantizer_kwargs)
self.num_quantizers = quantizer_kwargs["n_codebooks"]
self.quantize_on_decode = quantize_on_decode
self.noise_augment_dim = noise_augment_dim
def encode(self, x, return_info=False, **kwargs):
info = {}
info["pre_quantizer"] = x
if self.quantize_on_decode:
return x, info if return_info else x
z, codes, latents, commitment_loss, codebook_loss = self.quantizer(x, **kwargs)
output = {
"z": z,
"codes": codes,
"latents": latents,
"vq/commitment_loss": commitment_loss,
"vq/codebook_loss": codebook_loss,
}
output["vq/commitment_loss"] /= self.num_quantizers
output["vq/codebook_loss"] /= self.num_quantizers
info.update(output)
if return_info:
return output["z"], info
return output["z"]
def decode(self, x):
if self.quantize_on_decode:
x = self.quantizer(x)[0]
if self.noise_augment_dim > 0:
noise = torch.randn(
x.shape[0], self.noise_augment_dim, x.shape[-1]
).type_as(x)
x = torch.cat([x, noise], dim=1)
return x
def decode_tokens(self, codes, **kwargs):
latents, _, _ = self.quantizer.from_codes(codes)
return self.decode(latents, **kwargs)
class DACRVQVAEBottleneck(DiscreteBottleneck):
def __init__(self, quantize_on_decode=False, **quantizer_kwargs):
super().__init__(
num_quantizers=quantizer_kwargs["n_codebooks"],
codebook_size=quantizer_kwargs["codebook_size"],
tokens_id="codes",
)
self.quantizer = DACResidualVQ(**quantizer_kwargs)
self.num_quantizers = quantizer_kwargs["n_codebooks"]
self.quantize_on_decode = quantize_on_decode
def encode(self, x, return_info=False, n_quantizers: int = None):
info = {}
mean, scale = x.chunk(2, dim=1)
x, kl = vae_sample(mean, scale)
info["pre_quantizer"] = x
info["kl"] = kl
if self.quantize_on_decode:
return x, info if return_info else x
z, codes, latents, commitment_loss, codebook_loss = self.quantizer(
x, n_quantizers=n_quantizers
)
output = {
"z": z,
"codes": codes,
"latents": latents,
"vq/commitment_loss": commitment_loss,
"vq/codebook_loss": codebook_loss,
}
output["vq/commitment_loss"] /= self.num_quantizers
output["vq/codebook_loss"] /= self.num_quantizers
info.update(output)
if return_info:
return output["z"], info
return output["z"]
def decode(self, x):
if self.quantize_on_decode:
x = self.quantizer(x)[0]
return x
def decode_tokens(self, codes, **kwargs):
latents, _, _ = self.quantizer.from_codes(codes)
return self.decode(latents, **kwargs)
class FSQBottleneck(DiscreteBottleneck):
def __init__(self, noise_augment_dim=0, **kwargs):
super().__init__(
num_quantizers=kwargs.get("num_codebooks", 1),
codebook_size=np.prod(kwargs["levels"]),
tokens_id="quantizer_indices",
)
self.noise_augment_dim = noise_augment_dim
self.quantizer = FSQ(
**kwargs, allowed_dtypes=[torch.float16, torch.float32, torch.float64]
)
def encode(self, x, return_info=False):
info = {}
orig_dtype = x.dtype
x = x.float()
x = rearrange(x, "b c n -> b n c")
x, indices = self.quantizer(x)
x = rearrange(x, "b n c -> b c n")
x = x.to(orig_dtype)
# Reorder indices to match the expected format
indices = rearrange(indices, "b n q -> b q n")
info["quantizer_indices"] = indices
if return_info:
return x, info
else:
return x
def decode(self, x):
if self.noise_augment_dim > 0:
noise = torch.randn(
x.shape[0], self.noise_augment_dim, x.shape[-1]
).type_as(x)
x = torch.cat([x, noise], dim=1)
return x
def decode_tokens(self, tokens, **kwargs):
latents = self.quantizer.indices_to_codes(tokens)
return self.decode(latents, **kwargs)