File size: 3,800 Bytes
01fdb75 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 | import torch
import copy
import timm
from torch.nn import Parameter
from src.utils.no_grad import no_grad
from typing import Callable, Iterator, Tuple
from timm.data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
from torchvision.transforms import Normalize
from src.diffusion.base.training import *
from src.diffusion.base.scheduling import BaseScheduler
def inverse_sigma(alpha, sigma):
return 1/sigma**2
def snr(alpha, sigma):
return alpha/sigma
def minsnr(alpha, sigma, threshold=5):
return torch.clip(alpha/sigma, min=threshold)
def maxsnr(alpha, sigma, threshold=5):
return torch.clip(alpha/sigma, max=threshold)
def constant(alpha, sigma):
return 1
def time_shift_fn(t, timeshift=1.0):
return t/(t+(1-t)*timeshift)
class REPATrainer(BaseTrainer):
def __init__(
self,
scheduler: BaseScheduler,
loss_weight_fn:Callable=constant,
feat_loss_weight: float=0.5,
lognorm_t=False,
timeshift=1.0,
encoder:nn.Module=None,
align_layer=8,
proj_denoiser_dim=256,
proj_hidden_dim=256,
proj_encoder_dim=256,
P_mean=-0.8,
P_std=0.8,
t_eps=0.05,
*args,
**kwargs
):
super().__init__(*args, **kwargs)
self.lognorm_t = lognorm_t
self.scheduler = scheduler
self.timeshift = timeshift
self.loss_weight_fn = loss_weight_fn
self.feat_loss_weight = feat_loss_weight
self.align_layer = align_layer
self.encoder = encoder
no_grad(self.encoder)
self.proj = nn.Sequential(
nn.Sequential(
nn.Linear(proj_denoiser_dim, proj_hidden_dim),
nn.SiLU(),
nn.Linear(proj_hidden_dim, proj_hidden_dim),
nn.SiLU(),
nn.Linear(proj_hidden_dim, proj_encoder_dim),
)
)
self.P_mean = P_mean
self.P_std = P_std
self.t_eps = t_eps
def _impl_trainstep(self, net, ema_net, solver, x, y, metadata=None):
raw_images = metadata["raw_image"]
batch_size, c, height, width = x.shape
if self.lognorm_t:
base_t = (torch.randn(batch_size, device=x.device, dtype=torch.float32)*self.P_std+self.P_mean).sigmoid()
else:
base_t = torch.rand((batch_size), device=x.device, dtype=torch.float32)
t = time_shift_fn(base_t, self.timeshift) #.to(x.dtype)
noise = torch.randn_like(x)
alpha = self.scheduler.alpha(t)
dalpha = self.scheduler.dalpha(t)
sigma = self.scheduler.sigma(t)
dsigma = self.scheduler.dsigma(t)
x_t = alpha * x + noise * sigma
v_t = (x - x_t) / (1 - t.view(-1, 1, 1, 1)).clamp_min(self.t_eps)
# v_t = dalpha * x + dsigma * noise
out, src_feature = net(x_t, t, y, return_layer=self.align_layer)
src_feature = self.proj(src_feature)
out = (out - x_t) / (1 - t.view(-1, 1, 1, 1)).clamp_min(self.t_eps) # compute v from pred x
with torch.no_grad():
dst_feature = self.encoder(raw_images)
cos_sim = torch.nn.functional.cosine_similarity(src_feature, dst_feature, dim=-1)
cos_loss = 1 - cos_sim
weight = self.loss_weight_fn(alpha, sigma)
fm_loss = weight*(out - v_t)**2
out = dict(
fm_loss=fm_loss.mean(),
cos_loss=cos_loss.mean(),
loss=fm_loss.mean() + self.feat_loss_weight*cos_loss.mean(),
)
return out
def state_dict(self, *args, destination=None, prefix="", keep_vars=False):
self.proj.state_dict(
destination=destination,
prefix=prefix + "proj.",
keep_vars=keep_vars) |