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import logging
from dataclasses import dataclass
import torch.nn as nn
import torch.nn.functional as F
from torch import Tensor, nn
from torch.nn.utils.parametrizations import weight_norm
from ...common import Normalizer
logger = logging.getLogger(__name__)
@dataclass
class IRMAEOutput:
latent: Tensor # latent vector
decoded: Tensor | None # decoder output, include extra dim
class ResBlock(nn.Sequential):
def __init__(self, channels, dilations=[1, 2, 4, 8]):
wn = weight_norm
super().__init__(
nn.GroupNorm(32, channels),
nn.GELU(),
wn(nn.Conv1d(channels, channels, 3, padding="same", dilation=dilations[0])),
nn.GroupNorm(32, channels),
nn.GELU(),
wn(nn.Conv1d(channels, channels, 3, padding="same", dilation=dilations[1])),
nn.GroupNorm(32, channels),
nn.GELU(),
wn(nn.Conv1d(channels, channels, 3, padding="same", dilation=dilations[2])),
nn.GroupNorm(32, channels),
nn.GELU(),
wn(nn.Conv1d(channels, channels, 3, padding="same", dilation=dilations[3])),
)
def forward(self, x: Tensor):
return x + super().forward(x)
class IRMAE(nn.Module):
def __init__(
self,
input_dim,
output_dim,
latent_dim,
hidden_dim=1024,
num_irms=4,
):
"""
Args:
input_dim: input dimension
output_dim: output dimension
latent_dim: latent dimension
hidden_dim: hidden layer dimension
num_irm_matrics: number of implicit rank minimization matrices
norm: normalization layer
"""
self.input_dim = input_dim
super().__init__()
self.encoder = nn.Sequential(
nn.Conv1d(input_dim, hidden_dim, 3, padding="same"),
*[ResBlock(hidden_dim) for _ in range(4)],
# Try to obtain compact representation (https://proceedings.neurips.cc/paper/2020/file/a9078e8653368c9c291ae2f8b74012e7-Paper.pdf)
*[nn.Conv1d(hidden_dim if i == 0 else latent_dim, latent_dim, 1, bias=False) for i in range(num_irms)],
nn.Tanh(),
)
self.decoder = nn.Sequential(
nn.Conv1d(latent_dim, hidden_dim, 3, padding="same"),
*[ResBlock(hidden_dim) for _ in range(4)],
nn.Conv1d(hidden_dim, output_dim, 1),
)
self.head = nn.Sequential(
nn.Conv1d(output_dim, hidden_dim, 3, padding="same"),
nn.GELU(),
nn.Conv1d(hidden_dim, input_dim, 1),
)
self.estimator = Normalizer()
def encode(self, x):
"""
Args:
x: (b c t) tensor
"""
z = self.encoder(x) # (b c t)
_ = self.estimator(z) # Estimate the glboal mean and std of z
self.stats = {}
self.stats["z_mean"] = z.mean().item()
self.stats["z_std"] = z.std().item()
self.stats["z_abs_68"] = z.abs().quantile(0.6827).item()
self.stats["z_abs_95"] = z.abs().quantile(0.9545).item()
self.stats["z_abs_99"] = z.abs().quantile(0.9973).item()
return z
def decode(self, z):
"""
Args:
z: (b c t) tensor
"""
return self.decoder(z)
def forward(self, x, skip_decoding=False):
"""
Args:
x: (b c t) tensor
skip_decoding: if True, skip the decoding step
"""
z = self.encode(x) # q(z|x)
if skip_decoding:
# This speeds up the training in cfm only mode
decoded = None
else:
decoded = self.decode(z) # p(x|z)
predicted = self.head(decoded)
self.losses = dict(mse=F.mse_loss(predicted, x))
return IRMAEOutput(latent=z, decoded=decoded)