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import math | |
import torch | |
import torch.nn.functional as F | |
from torch import nn | |
from einops import reduce | |
from tqdm.auto import tqdm | |
from functools import partial | |
from .transformer import Transformer | |
from ..model_utils import default, identity, extract | |
from .control import * | |
import mlflow.pyfunc | |
import mlflow | |
from mlflow.models import infer_signature | |
# import matplotlib.pyplot as plt | |
# images_cache = [] | |
def linear_beta_schedule(timesteps): | |
scale = 1000 / timesteps | |
beta_start = scale * 0.0001 | |
beta_end = scale * 0.02 | |
return torch.linspace(beta_start, beta_end, timesteps, dtype=torch.float64) | |
def cosine_beta_schedule(timesteps, s=0.008): | |
""" | |
cosine schedule | |
as proposed in https://openreview.net/forum?id=-NEXDKk8gZ | |
""" | |
steps = timesteps + 1 | |
x = torch.linspace(0, timesteps, steps, dtype=torch.float64) | |
alphas_cumprod = torch.cos(((x / timesteps) + s) / (1 + s) * math.pi * 0.5) ** 2 | |
alphas_cumprod = alphas_cumprod / alphas_cumprod[0] | |
betas = 1 - (alphas_cumprod[1:] / alphas_cumprod[:-1]) | |
return torch.clip(betas, 0, 0.999) | |
class Tiffusion(nn.Module): | |
def __init__( | |
self, | |
seq_length, | |
feature_size, | |
n_layer_enc=3, | |
n_layer_dec=6, | |
d_model=None, | |
timesteps=1000, | |
sampling_timesteps=None, | |
loss_type="l1", | |
beta_schedule="cosine", | |
n_heads=4, | |
mlp_hidden_times=4, | |
eta=0.0, | |
attn_pd=0.0, | |
resid_pd=0.0, | |
kernel_size=None, | |
padding_size=None, | |
use_ff=True, | |
reg_weight=None, | |
control_signal={}, | |
moving_average=False, | |
**kwargs, | |
): | |
super(Tiffusion, self).__init__() | |
self.eta, self.use_ff = eta, use_ff | |
self.seq_length = seq_length | |
self.feature_size = feature_size | |
self.ff_weight = default(reg_weight, math.sqrt(self.seq_length) / 5) | |
self.sum_weight = default(reg_weight, math.sqrt(self.seq_length // 10) / 50) | |
self.training_control_signal = control_signal # training control signal | |
self.moving_average = moving_average | |
self.model: Transformer = Transformer( | |
n_feat=feature_size, | |
n_channel=seq_length, | |
n_layer_enc=n_layer_enc, | |
n_layer_dec=n_layer_dec, | |
n_heads=n_heads, | |
attn_pdrop=attn_pd, | |
resid_pdrop=resid_pd, | |
mlp_hidden_times=mlp_hidden_times, | |
max_len=seq_length, | |
n_embd=d_model, | |
conv_params=[kernel_size, padding_size], | |
**kwargs, | |
) | |
if beta_schedule == "linear": | |
betas = linear_beta_schedule(timesteps) | |
elif beta_schedule == "cosine": | |
betas = cosine_beta_schedule(timesteps) | |
else: | |
raise ValueError(f"unknown beta schedule {beta_schedule}") | |
alphas = 1.0 - betas | |
alphas_cumprod = torch.cumprod(alphas, dim=0) | |
alphas_cumprod_prev = F.pad(alphas_cumprod[:-1], (1, 0), value=1.0) | |
(timesteps,) = betas.shape | |
self.num_timesteps = int(timesteps) | |
self.loss_type = loss_type | |
# sampling related parameters | |
self.sampling_timesteps = default( | |
sampling_timesteps, timesteps | |
) # default num sampling timesteps to number of timesteps at training | |
assert self.sampling_timesteps <= timesteps | |
self.fast_sampling = self.sampling_timesteps < timesteps | |
# helper function to register buffer from float64 to float32 | |
register_buffer = lambda name, val: self.register_buffer( | |
name, val.to(torch.float32) | |
) | |
register_buffer("betas", betas) | |
register_buffer("alphas_cumprod", alphas_cumprod) | |
register_buffer("alphas_cumprod_prev", alphas_cumprod_prev) | |
# calculations for diffusion q(x_t | x_{t-1}) and others | |
register_buffer("sqrt_alphas_cumprod", torch.sqrt(alphas_cumprod)) | |
register_buffer( | |
"sqrt_one_minus_alphas_cumprod", torch.sqrt(1.0 - alphas_cumprod) | |
) | |
register_buffer("log_one_minus_alphas_cumprod", torch.log(1.0 - alphas_cumprod)) | |
register_buffer("sqrt_recip_alphas_cumprod", torch.sqrt(1.0 / alphas_cumprod)) | |
register_buffer( | |
"sqrt_recipm1_alphas_cumprod", torch.sqrt(1.0 / alphas_cumprod - 1) | |
) | |
# calculations for posterior q(x_{t-1} | x_t, x_0) | |
posterior_variance = ( | |
betas * (1.0 - alphas_cumprod_prev) / (1.0 - alphas_cumprod) | |
) | |
# above: equal to 1. / (1. / (1. - alpha_cumprod_tm1) + alpha_t / beta_t) | |
register_buffer("posterior_variance", posterior_variance) | |
# below: log calculation clipped because the posterior variance is 0 at the beginning of the diffusion chain | |
register_buffer( | |
"posterior_log_variance_clipped", | |
torch.log(posterior_variance.clamp(min=1e-20)), | |
) | |
register_buffer( | |
"posterior_mean_coef1", | |
betas * torch.sqrt(alphas_cumprod_prev) / (1.0 - alphas_cumprod), | |
) | |
register_buffer( | |
"posterior_mean_coef2", | |
(1.0 - alphas_cumprod_prev) * torch.sqrt(alphas) / (1.0 - alphas_cumprod), | |
) | |
# calculate reweighting | |
register_buffer( | |
"loss_weight", | |
torch.sqrt(alphas) * torch.sqrt(1.0 - alphas_cumprod) / betas / 100, | |
) | |
def predict_noise_from_start(self, x_t, t, x0): | |
return ( | |
extract(self.sqrt_recip_alphas_cumprod, t, x_t.shape) * x_t - x0 | |
) / extract(self.sqrt_recipm1_alphas_cumprod, t, x_t.shape) | |
def predict_start_from_noise(self, x_t, t, noise): | |
return ( | |
extract(self.sqrt_recip_alphas_cumprod, t, x_t.shape) * x_t | |
- extract(self.sqrt_recipm1_alphas_cumprod, t, x_t.shape) * noise | |
) | |
def q_posterior(self, x_start, x_t, t): | |
posterior_mean = ( | |
extract(self.posterior_mean_coef1, t, x_t.shape) * x_start | |
+ extract(self.posterior_mean_coef2, t, x_t.shape) * x_t | |
) | |
posterior_variance = extract(self.posterior_variance, t, x_t.shape) | |
posterior_log_variance_clipped = extract( | |
self.posterior_log_variance_clipped, t, x_t.shape | |
) | |
return posterior_mean, posterior_variance, posterior_log_variance_clipped | |
def output(self, x, t, padding_masks=None, control_signal=None): | |
# if ss:=control_signal.get("sum") is not None and len(ss.shape) == 1: | |
# bs = x.shape[0] | |
# control_signal["sum"] = ss.unsqueeze(0).repeat(bs, 1) | |
# print("control_signal", control_signal) | |
trend, season = self.model( | |
x, t, padding_masks=padding_masks, control_signal=control_signal | |
) | |
model_output = trend + season | |
return model_output | |
def model_predictions( | |
self, x, t, clip_x_start=False, padding_masks=None, control_signal=None | |
): | |
if padding_masks is None: | |
padding_masks = torch.ones( | |
x.shape[0], self.seq_length, dtype=bool, device=x.device | |
) | |
maybe_clip = ( | |
partial(torch.clamp, min=-1.0, max=1.0) if clip_x_start else identity | |
) | |
x_start = self.output(x, t, padding_masks, control_signal=control_signal) | |
x_start = maybe_clip(x_start) | |
pred_noise = self.predict_noise_from_start(x, t, x_start) | |
return pred_noise, x_start | |
def p_mean_variance(self, x, t, clip_denoised=True, control_signal=None): | |
_, x_start = self.model_predictions(x, t, control_signal=control_signal) | |
if clip_denoised: | |
x_start.clamp_(-1.0, 1.0) | |
model_mean, posterior_variance, posterior_log_variance = self.q_posterior( | |
x_start=x_start, x_t=x, t=t | |
) | |
return model_mean, posterior_variance, posterior_log_variance, x_start | |
def p_sample(self, x, t: int, clip_denoised=True, control_signal=None): | |
batched_times = torch.full((x.shape[0],), t, device=x.device, dtype=torch.long) | |
model_mean, _, model_log_variance, x_start = self.p_mean_variance( | |
x=x, t=batched_times, clip_denoised=clip_denoised, control_signal=control_signal | |
) | |
noise = torch.randn_like(x) if t > 0 else 0.0 # no noise if t == 0 | |
pred_img = model_mean + (0.5 * model_log_variance).exp() * noise | |
return pred_img, x_start | |
def sample(self, shape, control_signal=None): | |
device = self.betas.device | |
img = torch.randn(shape, device=device) | |
for t in tqdm( | |
reversed(range(0, self.num_timesteps)), | |
desc="sampling loop time step", | |
total=self.num_timesteps, | |
): | |
img, _ = self.p_sample(img, t, control_signal=control_signal) | |
return img | |
def fast_sample(self, shape, clip_denoised=True, model_kwargs=None, | |
): | |
batch, device, total_timesteps, sampling_timesteps, eta = ( | |
shape[0], | |
self.betas.device, | |
self.num_timesteps, | |
self.sampling_timesteps, | |
self.eta, | |
) | |
# [-1, 0, 1, 2, ..., T-1] when sampling_timesteps == total_timesteps | |
times = torch.linspace(-1, total_timesteps - 1, steps=sampling_timesteps + 1) | |
times = list(reversed(times.int().tolist())) | |
time_pairs = list( | |
zip(times[:-1], times[1:]) | |
) # [(T-1, T-2), (T-2, T-3), ..., (1, 0), (0, -1)] | |
img = torch.randn(shape, device=device) | |
for time, time_next in tqdm(time_pairs, desc="sampling loop time step"): | |
time_cond = torch.full((batch,), time, device=device, dtype=torch.long) | |
pred_noise, x_start, *_ = self.model_predictions( | |
img, time_cond, clip_x_start=clip_denoised, | |
control_signal=model_kwargs.get("model_control_signal", {}) if model_kwargs else {} | |
) | |
if time_next < 0: | |
img = x_start | |
continue | |
alpha = self.alphas_cumprod[time] | |
alpha_next = self.alphas_cumprod[time_next] | |
sigma = ( | |
eta * ((1 - alpha / alpha_next) * (1 - alpha_next) / (1 - alpha)).sqrt() | |
) | |
c = (1 - alpha_next - sigma**2).sqrt() | |
noise = torch.randn_like(img) | |
img = x_start * alpha_next.sqrt() + c * pred_noise + sigma * noise | |
return img | |
def generate_mts(self, batch_size=16): | |
feature_size, seq_length = self.feature_size, self.seq_length | |
sample_fn = self.fast_sample if self.fast_sampling else self.sample | |
return sample_fn((batch_size, seq_length, feature_size)) | |
def generate_mts_infill(self, target, partial_mask=None, clip_denoised=True, model_kwargs=None): | |
sample_fn = self.fast_sample_infill_float_mask # if self.fast_sampling else self.sample_infill | |
print("model_kwargs", model_kwargs) | |
print("partial_mask", partial_mask.shape) | |
print("target", target.shape) | |
return sample_fn( | |
shape=target.shape, | |
target=target, | |
sampling_timesteps=self.sampling_timesteps, | |
partial_mask=partial_mask, | |
clip_denoised=clip_denoised, | |
model_kwargs=model_kwargs | |
) | |
def loss_fn(self): | |
if self.loss_type == "l1": | |
return F.l1_loss | |
elif self.loss_type == "l2": | |
return F.mse_loss | |
else: | |
raise ValueError(f"invalid loss type {self.loss_type}") | |
def q_sample(self, x_start, t, noise=None): | |
noise = default(noise, lambda: torch.randn_like(x_start)) | |
return ( | |
extract(self.sqrt_alphas_cumprod, t, x_start.shape) * x_start | |
+ extract(self.sqrt_one_minus_alphas_cumprod, t, x_start.shape) * noise | |
) | |
def calculate_dynamic_window(self, t: torch.Tensor) -> torch.Tensor: | |
# Batch-wise time point normalization | |
t_min = 0 # t.min() | |
t_max = 500 # t.max() | |
# t_normalized = (t - t_min) / (t_max - t_min) | |
# Compute window sizes | |
# windows = ((t_normalized.exp2() - 1) * 15 // 1 + 1).long() | |
# plt.scatter(t, ( (5 ** ((t - 0) / 1000))) * 15 // 7 + 1) | |
windows = ((5 ** ( t / 500)) * 15 // 5 - 2).long() | |
return windows | |
def torch_moving_average(self, bs: torch.Tensor, t: torch.Tensor) -> torch.Tensor: | |
""" | |
Compute moving average for a time series tensor with dynamically calculated | |
window sizes for each sample. | |
Parameters: | |
----------- | |
bs : torch.Tensor | |
Input time series tensor of shape (batch_size, sequence_length, features) | |
t : torch.Tensor | |
Time points tensor of shape (batch_size, sequence_length) | |
Returns: | |
-------- | |
torch.Tensor | |
Moving average tensor with the same shape as input | |
""" | |
# Get tensor dimensions | |
batch_size, total_seq_length, num_features = bs.shape | |
# Calculate dynamic window sizes for each sample | |
windows = self.calculate_dynamic_window(t) | |
# Create output tensor initialized with the original values | |
moving_avg = bs.clone() | |
# Compute moving average for each sample and time point | |
for b in range(batch_size): | |
for i in range(total_seq_length): | |
# Get the window size for this sample and time point | |
current_window = windows[b].item() | |
# Determine the start and end of the window | |
start = max(0, i - current_window + 1) | |
window = bs[b:b+1, start:i+1, :] | |
# Compute average along the time dimension | |
window_avg = window.mean(dim=1) | |
# Replace values where we have enough previous steps | |
if i >= current_window - 1: | |
moving_avg[b, i, :] = window_avg | |
return moving_avg | |
def _train_loss( | |
self, | |
x_start, | |
t, | |
target=None, | |
noise=None, | |
padding_masks=None, | |
control_signal=None, | |
): | |
noise = default(noise, lambda: torch.randn_like(x_start)) | |
if target is None: | |
target = x_start | |
x = self.q_sample(x_start=x_start, t=t, noise=noise) # noise sample | |
# with torch.no_grad(): | |
# if control_signal is None: | |
# control_signal = { | |
# "sum": target.mean(1), | |
# "top-peak-position": target.topk(self.seq_length // 20, dim=1)[1], | |
# } # .unsqueeze(-1) | |
# # elif self.control_sum: | |
# # ss = control_signal.get("sum") | |
# # if len(ss.shape) == 1: | |
# # bs = x.shape[0] | |
# # control_signal["sum"] = ss.unsqueeze(0).repeat(bs, 1) | |
# # control_signal = control_signal | |
# else: | |
# control_signal = {} | |
model_out = self.output(x, t, padding_masks, control_signal=control_signal) | |
# moving average according to the timestamp t, t larger means more stable, less noise | |
if self.moving_average: | |
target = self.torch_moving_average(target.cpu(), t.cpu()).to(model_out.device) | |
train_loss = self.loss_fn(model_out, target, reduction="none") | |
fourier_loss = torch.tensor([0.0]) | |
if self.use_ff: | |
fft1 = torch.fft.fft(model_out.transpose(1, 2), norm="forward") | |
fft2 = torch.fft.fft(target.transpose(1, 2), norm="forward") | |
fft1, fft2 = fft1.transpose(1, 2), fft2.transpose(1, 2) | |
fourier_loss = self.loss_fn( | |
torch.real(fft1), torch.real(fft2), reduction="none" | |
) + self.loss_fn(torch.imag(fft1), torch.imag(fft2), reduction="none") | |
train_loss += self.ff_weight * fourier_loss | |
# if self.control_sum: | |
# train_loss += ( | |
# self.loss_fn(model_out[..., 0].sum(1), target[..., 0].sum(1)) | |
# / self.seq_length | |
# ) | |
# * self.sum_weight | |
train_loss = reduce(train_loss, "b ... -> b (...)", "mean") | |
train_loss = train_loss * extract(self.loss_weight, t, train_loss.shape) | |
return train_loss.mean() | |
# fmt: off | |
def forward(self, x, **kwargs): | |
b, c, n, device, feature_size, = *x.shape, x.device, self.feature_size | |
assert n == feature_size, f'number of variable must be {feature_size}' | |
t = torch.randint(0, self.num_timesteps, (b,), device=device).long() | |
return self._train_loss(x_start=x, t=t, **kwargs) | |
def return_components(self, x, t: int): | |
b, c, n, device, feature_size, = *x.shape, x.device, self.feature_size | |
assert n == feature_size, f'number of variable must be {feature_size}' | |
t = torch.tensor([t]) | |
t = t.repeat(b).to(device) | |
x = self.q_sample(x, t) | |
trend, season, residual = self.model(x, t, return_res=True) | |
return trend, season, residual, x | |
# fmt: on | |
def fast_sample_infill_float_mask( | |
self, | |
shape, | |
target: torch.Tensor, # target time series # [B, L, C] | |
sampling_timesteps, | |
partial_mask: torch.Tensor = None, # float mask between 0 and 1 # [B, L, C] | |
clip_denoised=True, | |
model_kwargs=None, | |
): | |
batch, device, total_timesteps, eta = ( | |
shape[0], | |
self.betas.device, | |
self.num_timesteps, | |
self.eta, | |
) | |
# [-1, 0, 1, 2, ..., T-1] when sampling_timesteps == total_timesteps | |
times = torch.linspace(-1, total_timesteps - 1, steps=sampling_timesteps + 1) | |
times = list(reversed(times.int().tolist())) | |
time_pairs = list( | |
zip(times[:-1], times[1:]) | |
) # [(T-1, T-2), (T-2, T-3), ..., (1, 0), (0, -1)] | |
# Initialize with noise | |
img = torch.randn(shape, device=device) # [B, L, C] | |
for time, time_next in tqdm( | |
time_pairs, desc="conditional sampling loop time step" | |
): | |
time_cond = torch.full((batch,), time, device=device, dtype=torch.long) | |
pred_noise, x_start, *_ = self.model_predictions( | |
img, | |
time_cond, | |
clip_x_start=clip_denoised, | |
control_signal=model_kwargs.get("model_control_signal", {}), | |
) | |
if time_next < 0: | |
img = x_start | |
continue | |
# Compute the predicted mean | |
alpha = self.alphas_cumprod[time] | |
alpha_next = self.alphas_cumprod[time_next] | |
sigma = ( | |
eta * ((1 - alpha / alpha_next) * (1 - alpha_next) / (1 - alpha)).sqrt() | |
) | |
c = (1 - alpha_next - sigma**2).sqrt() | |
noise = torch.randn_like(img) | |
pred_mean = x_start * alpha_next.sqrt() + c * pred_noise | |
img = pred_mean + sigma * noise | |
# # Apply partial mask to the current sample | |
# if partial_mask is not None: | |
# target_t = self.q_sample(target, t=time_cond) | |
# img = img * (1.0 - partial_mask) + target_t * partial_mask | |
# Langevin Dynamics part for additional gradient updates | |
img = self.langevin_fn( | |
sample=img, | |
mean=pred_mean, | |
sigma=sigma, | |
t=time_cond, | |
tgt_embs=target, | |
partial_mask=partial_mask, | |
enable_float_mask=True, | |
**model_kwargs, | |
) | |
img = img * (1 - partial_mask) + target * partial_mask | |
img = img * (1 - partial_mask) + target * partial_mask | |
return img | |
def fast_sample_infill( | |
self, | |
shape, | |
target, | |
sampling_timesteps, | |
partial_mask=None, | |
clip_denoised=True, | |
model_kwargs=None, | |
): | |
batch, device, total_timesteps, eta = ( | |
shape[0], | |
self.betas.device, | |
self.num_timesteps, | |
self.eta, | |
) | |
# [-1, 0, 1, 2, ..., T-1] when sampling_timesteps == total_timesteps | |
times = torch.linspace(-1, total_timesteps - 1, steps=sampling_timesteps + 1) | |
times = list(reversed(times.int().tolist())) | |
time_pairs = list( | |
zip(times[:-1], times[1:]) | |
) # [(T-1, T-2), (T-2, T-3), ..., (1, 0), (0, -1)] | |
img = torch.randn(shape, device=device) | |
for time, time_next in tqdm( | |
time_pairs, desc="conditional sampling loop time step" | |
): | |
time_cond = torch.full((batch,), time, device=device, dtype=torch.long) | |
pred_noise, x_start, *_ = self.model_predictions( | |
img, | |
time_cond, | |
clip_x_start=clip_denoised, | |
control_signal=model_kwargs.get("model_control_signal", {}), | |
) | |
if time_next < 0: | |
img = x_start | |
continue | |
alpha = self.alphas_cumprod[time] | |
alpha_next = self.alphas_cumprod[time_next] | |
sigma = ( | |
eta * ((1 - alpha / alpha_next) * (1 - alpha_next) / (1 - alpha)).sqrt() | |
) | |
c = (1 - alpha_next - sigma**2).sqrt() | |
pred_mean = x_start * alpha_next.sqrt() + c * pred_noise | |
noise = torch.randn_like(img) | |
img = pred_mean + sigma * noise | |
img = self.langevin_fn( | |
sample=img, | |
mean=pred_mean, | |
sigma=sigma, | |
t=time_cond, | |
tgt_embs=target, | |
partial_mask=partial_mask, | |
# gradient_control_signal=model_kwargs.get("gradient_control_signal", {}), | |
# model_control_signal=model_kwargs.get("model_control_signal", {}), | |
**model_kwargs, | |
) | |
target_t = self.q_sample(target, t=time_cond) | |
img[partial_mask] = target_t[partial_mask] | |
img[partial_mask] = target[partial_mask] | |
return img | |
def sample_infill( | |
self, | |
shape, | |
target, | |
partial_mask=None, | |
clip_denoised=True, | |
model_kwargs=None, | |
): | |
""" | |
Generate samples from the model and yield intermediate samples from | |
each timestep of diffusion. | |
""" | |
batch, device = shape[0], self.betas.device | |
img = torch.randn(shape, device=device) | |
for t in tqdm( | |
reversed(range(0, self.num_timesteps)), | |
desc="conditional sampling loop time step", | |
total=self.num_timesteps, | |
): | |
img = self.p_sample_infill( | |
x=img, | |
t=t, | |
clip_denoised=clip_denoised, | |
target=target, | |
partial_mask=partial_mask, | |
model_kwargs=model_kwargs, | |
) | |
img[partial_mask] = target[partial_mask] | |
return img | |
def p_sample_infill( | |
self, | |
x, | |
target, | |
t: int, | |
partial_mask=None, | |
clip_denoised=True, | |
model_kwargs=None, | |
): | |
b, *_, device = *x.shape, self.betas.device | |
batched_times = torch.full((x.shape[0],), t, device=x.device, dtype=torch.long) | |
model_mean, _, model_log_variance, _ = self.p_mean_variance( | |
x=x, t=batched_times, clip_denoised=clip_denoised, control_signal=model_kwargs.get("model_control_signal", {}) | |
# don't pass parameters to control signal, for model itself | |
# Otherwise pass: control_signal=model_kwargs.get("control_signal", {}) | |
) | |
noise = torch.randn_like(x) if t > 0 else 0.0 # no noise if t == 0 | |
sigma = (0.5 * model_log_variance).exp() | |
pred_img = model_mean + sigma * noise | |
pred_img = self.langevin_fn( | |
sample=pred_img, | |
mean=model_mean, | |
sigma=sigma, | |
t=batched_times, | |
tgt_embs=target, | |
partial_mask=partial_mask, | |
# control_signal=model_kwargs.get("gradient_control_signal", {}), | |
**model_kwargs, | |
) | |
# fix point (must passed points) | |
target_t = self.q_sample(target, t=batched_times) | |
pred_img[partial_mask] = target_t[partial_mask] | |
return pred_img | |
def classifier_guidance( | |
x: torch.Tensor, | |
t: torch.Tensor, | |
y: torch.Tensor, | |
classifier: torch.nn.Module | |
): | |
with torch.enable_grad(): | |
# 激活梯度计算 | |
x_with_grad = x.detach().requires_grad_(True) | |
# 获取 log 形式的概率分布 | |
logits = classifier(x_with_grad, t) | |
log_prob = F.log_softmax(logits, dim=-1) | |
# 选取出 y 对应的项 | |
selected = log_prob[range(len(logits)), y.view(-1)] | |
# 计算梯度 | |
return torch.autograd.grad(selected.sum(), x_with_grad)[0] | |
def regression_guidance( | |
x: torch.Tensor, | |
t: torch.Tensor, | |
target_sum: torch.Tensor, # Target sum value | |
sigma: float = 1.0 | |
): | |
""" | |
Compute gradient for guiding the sum of first channel to match target value | |
Args: | |
x: Input tensor [batch_size, channels, length] or [batch_size, length, channels] | |
t: Time steps | |
target_sum: Target sum value [batch_size] | |
sigma: Standard deviation for Gaussian likelihood | |
""" | |
# with torch.enable_grad(): | |
# x_with_grad = x.detach().requires_grad_(True) | |
# normalize to 0, 1 | |
# x_with_grad = (x + x.min()) / (x.max() - x.min()) | |
# x_with_grad = x / 2 + 0.5 # [-1,1 to 0,1] | |
x_with_grad = x | |
# Calculate sum of first channel/feature | |
# Assuming x shape is [batch_size, channels, length] or [batch_size, length, channels] | |
if x_with_grad.dim() == 3: | |
if x_with_grad.shape[1] < x_with_grad.shape[2]: # [B, C, L] | |
current_sum = x_with_grad[:1, 0] | |
current_sum = current_sum / 2 + 0.5 # [-1, 1 to 0, 1] | |
print("Current Sum: ", current_sum.max().item(), current_sum.min().item()) | |
current_sum = current_sum.sum(dim=1) # Sum over length | |
else: # [B, L, C] | |
current_sum = x_with_grad[:1, :, 0] | |
current_sum = current_sum / 2 + 0.5 # [-1, 1 to 0, 1] | |
print("Current Sum: ", current_sum.max().item(), current_sum.min().item()) | |
current_sum = current_sum.sum(dim=1) # Sum over length | |
# Compute log probability under Gaussian distribution | |
sigma = torch.log(t) / 5 | |
print("sigma", sigma) | |
if sigma.mean() == 0: | |
pred_std = torch.ones_like(current_sum) | |
else: | |
pred_std = torch.ones_like(current_sum) * sigma | |
log_prob = -0.5 * torch.log(2 * torch.pi * pred_std**2) - \ | |
(target_sum - current_sum)**2 / (2 * pred_std**2) | |
# print(target_sum, current_sum) | |
# print("Current Sum: ", current_sum.mean().item()) | |
# print("Current Diff: ", (target_sum - current_sum).mean().item()) | |
return log_prob.mean() | |
# return torch.autograd.grad(log_prob.sum(), x_with_grad)[0] | |
def langevin_fn( | |
self, | |
coef, | |
partial_mask, | |
tgt_embs, | |
learning_rate, | |
sample, | |
mean, | |
sigma, | |
t, | |
coef_=0.0, | |
gradient_control_signal={}, | |
model_control_signal={}, | |
**kwargs, | |
): | |
# we thus run more gradient updates at large diffusion step t to guide the generation then | |
# reduce the number of gradient steps in stages to accelerate sampling. | |
if t[0].item() < self.num_timesteps * 0.02 : | |
K = 0 | |
elif t[0].item() > self.num_timesteps * 0.9: | |
K = 3 | |
elif t[0].item() > self.num_timesteps * 0.75: | |
K = 2 | |
learning_rate = learning_rate * 0.5 | |
else: | |
K = 1 | |
learning_rate = learning_rate * 0.25 | |
input_embs_param = torch.nn.Parameter(sample) | |
# 获取时间相关的权重调整因子 | |
time_weight = get_time_dependent_weights(t[0], self.num_timesteps) | |
with torch.enable_grad(): | |
for iteration in range(K): | |
# x_i+1 = x_i + noise * grad(logp(x_i)) + sqrt(2*noise) * z_i | |
optimizer = torch.optim.Adagrad([input_embs_param], lr=learning_rate) | |
optimizer.zero_grad() | |
x_start = self.output( | |
x=input_embs_param, | |
t=t, | |
control_signal=model_control_signal, | |
) | |
if sigma.mean() == 0: | |
logp_term = ( | |
coef * ((mean - input_embs_param) ** 2 / 1.0).mean(dim=0).sum() | |
) | |
# determine the partical_mask is float | |
if kwargs.get("enable_float_mask", False): | |
infill_loss = (x_start * (partial_mask) - tgt_embs * (partial_mask)) ** 2 | |
else: | |
infill_loss = (x_start[partial_mask] - tgt_embs[partial_mask]) ** 2 | |
infill_loss = infill_loss.mean(dim=0).sum() | |
else: | |
logp_term = ( | |
coef | |
* ((mean - input_embs_param) ** 2 / sigma).mean(dim=0).sum() | |
) | |
if kwargs.get("enable_float_mask", False): | |
infill_loss = (x_start * (partial_mask) - tgt_embs * (partial_mask)) ** 2 | |
else: | |
infill_loss = (x_start[partial_mask] - tgt_embs[partial_mask]) ** 2 | |
infill_loss = (infill_loss / sigma.mean()).mean(dim=0).sum() | |
# 第二个等号后面最后一项消失了,因为当我们要求模型生成“狗”的图像时,扩散过程始终 | |
# 不变,对应的梯度也是0,可以抹掉。 | |
# https://lichtung612.github.io/posts/3-diffusion-models/ | |
# 第三个等号后面两项中,第一项是扩散模型本身的梯度引导,新增的只能是第二项,即classifier guidance只需要额外添加一个classifier的梯度来引导。 | |
# 控制信号损失 | |
gradient_scale = gradient_control_signal.get("gradient_scale", 1.0) # 全局梯度缩放因子 | |
# Add regression guidance for sum constraint | |
control_loss = 0 | |
# target_sum = | |
# normalize the sum to -1, 1 | |
# seq_length = input_embs_param.shape[1] | |
# target_sum = ((target_sum / seq_length ) * 2 - 1) * seq_length | |
# if target_sum:=gradient_control_signal.get("sum") is not None: | |
# # print("sigma", sigma.shape, sigma, end=" ") | |
# reg_nll = self.regression_guidance( | |
# x=input_embs_param, | |
# t=t, | |
# target_sum=target_sum, | |
# sigma=sigma | |
# ) | |
# control_loss += - gradient_control_signal.get("reg_weight", 1.0) * reg_nll * (5 - K) # (reg_gradient * ).sum() | |
# init control signal loss | |
auc_sum, peak_points, bar_regions, target_freq = \ | |
gradient_control_signal.get("auc"), gradient_control_signal.get("peak_points"), gradient_control_signal.get("bar_regions"), gradient_control_signal.get("target_freq") | |
# 1. 原有的sum控制 | |
if auc_sum is not None: | |
sum_weight = gradient_control_signal.get("auc_weight", 1.0) * time_weight | |
auc_loss = - sum_weight * sum_guidance( | |
x=input_embs_param, | |
t=t, | |
target_sum=auc_sum, | |
gradient_scale=gradient_scale, | |
segments=gradient_control_signal.get("segments", ()) | |
) | |
control_loss += auc_loss | |
# 峰值引导 | |
if peak_points is not None: | |
peak_weight = gradient_control_signal.get("peak_weight", 1.0) * time_weight | |
peak_loss = - peak_weight * peak_guidance( | |
x=input_embs_param, | |
t=t, | |
peak_points=peak_points, | |
window_size=gradient_control_signal.get("peak_window_size", 5), | |
alpha_1=gradient_control_signal.get("peak_alpha_1", 1.2), | |
gradient_scale=gradient_scale | |
) | |
control_loss += peak_loss | |
# 区间引导 | |
if bar_regions is not None: | |
bar_weight = gradient_control_signal.get("bar_weight", 1.0) * time_weight | |
bar_loss = -bar_weight * bar_guidance( | |
x=input_embs_param, | |
t=t, | |
bar_regions=bar_regions, | |
gradient_scale=gradient_scale | |
) | |
control_loss += bar_loss | |
# 频率引导 | |
if target_freq is not None: | |
freq_weight = gradient_control_signal.get("freq_weight", 1.0) * time_weight | |
freq_loss = -freq_weight * frequency_guidance( | |
x=input_embs_param, | |
t=t, | |
target_freq=target_freq, | |
freq_weight=freq_weight, | |
gradient_scale=gradient_scale | |
) | |
control_loss += freq_loss | |
loss = logp_term + infill_loss + control_loss | |
if iteration == 0: # Only print first iteration to avoid spam | |
# print(f"Losses - Diffusion: {logp_term:.4f}, Infill: {infill_loss:.4f}, Control: {control_loss:.4f}") | |
# if target_sum is not None: | |
# # Print current sum vs target for monitoring | |
# if x_start.shape[1] < x_start.shape[2]: # [B, C, L] | |
# current_sum = input_embs_param[:, 0].sum(dim=1) | |
# else: # [B, L, C] | |
# current_sum = input_embs_param[:, :, 0].sum(dim=1) | |
# print(f"Current sum: {current_sum.data}, Target sum: {target_sum}") | |
# print(f"Losses - Diffusion: {logp_term:.4f}\tInfill: {infill_loss:.4f}", end="\t") | |
# if auc_sum is not None: | |
# print(f"Sum Control: {auc_loss.item():.4f}", end="\t") | |
# if peak_points is not None: | |
# print(f"Peak Control: {peak_loss.item():.4f}", end="\t") | |
# if bar_regions is not None: | |
# print(f"Bar Control: {bar_loss.item():.4f}", end="\t") | |
# if target_freq is not None: | |
# print(f"Freq Control: {freq_loss.item():.4f}", end="\t") | |
# print() | |
pass | |
# loss = logp_term + infill_loss + auc_loss | |
# print(logp_term, infill_loss, auc_loss) | |
loss.backward() | |
optimizer.step() | |
torch.nn.utils.clip_grad_norm_([input_embs_param], gradient_control_signal.get("max_grad_norm", 1.0)) | |
# add more noise | |
epsilon = torch.randn_like(input_embs_param.data) | |
noise_scale = coef_ * sigma.mean().item() # * 2 | |
# noise_scale = noise_scale * time_weight # (1 - time_weight) # 随时间减少噪声 | |
input_embs_param = torch.nn.Parameter( | |
( | |
input_embs_param.data + noise_scale * epsilon | |
).detach() | |
) | |
if kwargs.get("enable_float_mask", False): | |
sample = sample * partial_mask + input_embs_param.data * (1 - partial_mask) | |
else: | |
sample[~partial_mask] = input_embs_param.data[~partial_mask] | |
# if t[0].item() % 10 == 9: | |
# print("Sampled Image") | |
# images_cache.append(plt.plot(sample[0,:,0].detach().cpu().numpy())[0]) | |
# if t[0].item() == 9: | |
# plt.show() | |
# images_cache.clear() | |
# plt.show() | |
# plt.savefig(f"sampled_{t[0].item()}.png") | |
# plt.plot(sample[0,:,0].detach().cpu().numpy()) | |
# plt.show() | |
return sample | |
# def load_weights(self, model_path): | |
# data = torch.load(model_path, map_location="cuda:0", weights_only=True) | |
# self.load_state_dict(data["model"]) | |
# print("Model weights loaded successfully") | |
def predict_weighted_points( | |
self, | |
observed_points: torch.Tensor, | |
observed_mask: torch.Tensor, | |
coef=1e-1, | |
stepsize=1e-1, | |
sampling_steps=50, | |
**kargs, | |
): | |
model_kwargs = {} | |
model_kwargs["coef"] = coef | |
model_kwargs["learning_rate"] = stepsize | |
model_kwargs = {**model_kwargs, **kargs} | |
assert len(observed_points.shape) == 2, "observed_points should be 2D, batch size = 1" | |
x = observed_points.unsqueeze(0) | |
float_mask = observed_mask.unsqueeze(0) # x != 0, 1 for observed, 0 for missing, bool tensor | |
binary_mask = float_mask.clone() | |
binary_mask[binary_mask > 0] = 1 | |
x = x * 2 - 1 # normalize | |
self.device = x.device | |
x, float_mask, binary_mask = x.to(self.device), float_mask.to(self.device), binary_mask.to(self.device) | |
if sampling_steps == self.num_timesteps: | |
print("normal sampling") | |
raise NotImplementedError | |
sample = self.ema.ema_model.sample_infill_float_mask( | |
shape=x.shape, | |
target=x * binary_mask, # x * t_m, 1 for observed, 0 for missing | |
partial_mask=float_mask, | |
model_kwargs=model_kwargs, | |
) | |
# x: partially noise : (batch_size, seq_length, feature_dim) | |
else: | |
print("fast sampling") | |
sample = self.fast_sample_infill_float_mask( | |
shape=x.shape, | |
target=x * binary_mask, # x * t_m, 1 for observed, 0 for missing | |
partial_mask=float_mask, | |
model_kwargs=model_kwargs, | |
sampling_timesteps=sampling_steps, | |
) | |
# unnormalize | |
sample = (sample + 1) / 2 | |
return sample.squeeze(0).detach().cpu().numpy() | |
def register_model(self, registered_model_name, model_path="tiffusion_model", conda_env=None): | |
"""Register the model with MLflow model registry. | |
Args: | |
registered_model_name: Name to register the model under | |
model_path: Local path to save model artifacts | |
conda_env: Custom conda environment for the model | |
""" | |
# Create basic conda env if not provided | |
if conda_env is None: | |
conda_env = { | |
'channels': ['defaults', 'conda-forge'], | |
'dependencies': [ | |
'python>=3.8', | |
'pytorch', | |
'einops', | |
'tqdm' | |
], | |
'name': 'tiffusion_env' | |
} | |
# Start an MLflow run | |
with mlflow.start_run() as run: | |
# Log model parameters | |
mlflow.log_params({ | |
"seq_length": self.seq_length, | |
"feature_size": self.feature_size, | |
"n_layer_enc": self.model.n_layer_enc, | |
"n_layer_dec": self.model.n_layer_dec, | |
"n_heads": self.model.n_heads, | |
"timesteps": self.num_timesteps, | |
"loss_type": self.loss_type | |
}) | |
# Create a custom Python model class for MLflow | |
class TiffusionWrapper(mlflow.pyfunc.PythonModel): | |
def __init__(self, model): | |
self.model = model | |
def predict(self, context, model_input): | |
# Generate predictions using the model | |
with torch.no_grad(): | |
result = self.model.generate_mts(batch_size=len(model_input)) | |
return result.numpy() | |
# Create wrapper instance | |
wrapped_model = TiffusionWrapper(self) | |
# Log and register the model | |
mlflow.pyfunc.log_model( | |
artifact_path=model_path, | |
python_model=wrapped_model, | |
conda_env=conda_env, | |
registered_model_name=registered_model_name | |
) | |
print(f"Model registered as: {registered_model_name}") | |
print(f"Run ID: {run.info.run_id}") | |
def load_registered_model(self, registered_model_name, version=None, stage=None): | |
"""Load a registered model from MLflow model registry. | |
Args: | |
registered_model_name: Name of registered model | |
version: Optional specific version to load | |
stage: Optional stage to load (e.g. 'Production', 'Staging') | |
""" | |
if version: | |
model_uri = f"models:/{registered_model_name}/{version}" | |
elif stage: | |
model_uri = f"models:/{registered_model_name}/{stage}" | |
else: | |
model_uri = f"models:/{registered_model_name}/latest" | |
return mlflow.pyfunc.load_model(model_uri) |