diff --git a/README.md b/README.md index 0faf6ac..943573a 100644 --- a/README.md +++ b/README.md @@ -529,13 +529,13 @@ Once built, images will be saved to the same directory the command is invoked - [x] be able to finely customize what to condition on (text, image embed) for specific unet in the cascade (super resolution ddpms near the end may not need too much conditioning) - [x] offload unets not being trained on to CPU for memory efficiency (for training each resolution unets separately) - [x] build out latent diffusion architecture, with the vq-reg variant (vqgan-vae), make it completely optional and compatible with cascading ddpms +- [x] for decoder, allow ability to customize objective (predict epsilon vs x0), in case latent diffusion does better with prediction of x0 - [ ] spend one day cleaning up tech debt in decoder - [ ] become an expert with unets, cleanup unet code, make it fully configurable, port all learnings over to https://github.com/lucidrains/x-unet - [ ] copy the cascading ddpm code to a separate repo (perhaps https://github.com/lucidrains/denoising-diffusion-pytorch) as the main contribution of dalle2 really is just the prior network - [ ] train on a toy task, offer in colab - [ ] extend diffusion head to use diffusion-gan (potentially using lightweight-gan) to speed up inference - [ ] bring in tools to train vqgan-vae -- [ ] for decoder, allow ability to customize objective (predict epsilon vs x0), in case latent diffusion does better with prediction of x0 - [ ] bring in vit-vqgan https://arxiv.org/abs/2110.04627 for the latent diffusion ## Citations diff --git a/dalle2_pytorch/dalle2_pytorch.py b/dalle2_pytorch/dalle2_pytorch.py index 39b778b..791b6c0 100644 --- a/dalle2_pytorch/dalle2_pytorch.py +++ b/dalle2_pytorch/dalle2_pytorch.py @@ -584,12 +584,14 @@ class DiffusionPrior(nn.Module): return posterior_mean, posterior_variance, posterior_log_variance_clipped def p_mean_variance(self, x, t, text_cond, clip_denoised: bool): + pred = self.net(x, t, **text_cond) + if self.predict_x0: - x_recon = self.net(x, t, **text_cond) + x_recon = pred # not 100% sure of this above line - for any spectators, let me know in the github issues (or through a pull request) if you know how to correctly do this # i'll be rereading https://arxiv.org/abs/2111.14822, where i think a similar approach is taken else: - x_recon = self.predict_start_from_noise(x, t = t, noise = self.net(x, t, **text_cond)) + x_recon = self.predict_start_from_noise(x, t = t, noise = pred) if clip_denoised and not self.predict_x0: x_recon.clamp_(-1., 1.) @@ -1119,6 +1121,7 @@ class Decoder(nn.Module): cond_drop_prob = 0.2, loss_type = 'l1', beta_schedule = 'cosine', + predict_x0 = False, image_sizes = None, # for cascading ddpm, image size at each stage lowres_cond_upsample_mode = 'bilinear', # cascading ddpm - low resolution upsample mode lowres_downsample_first = True, # cascading ddpm - resizes to lower resolution, then to next conditional resolution + blur @@ -1167,6 +1170,10 @@ class Decoder(nn.Module): self.image_sizes = image_sizes self.sample_channels = cast_tuple(self.channels, len(image_sizes)) + # predict x0 config + + self.predict_x0 = cast_tuple(predict_x0, len(unets)) + # cascading ddpm related stuff lowres_conditions = tuple(map(lambda t: t.lowres_cond, self.unets)) @@ -1285,34 +1292,47 @@ class Decoder(nn.Module): posterior_log_variance_clipped = extract(self.posterior_log_variance_clipped, t, x_t.shape) return posterior_mean, posterior_variance, posterior_log_variance_clipped - def p_mean_variance(self, unet, x, t, image_embed, text_encodings = None, lowres_cond_img = None, clip_denoised = True, cond_scale = 1.): - pred_noise = unet.forward_with_cond_scale(x, t, image_embed = image_embed, text_encodings = text_encodings, cond_scale = cond_scale, lowres_cond_img = lowres_cond_img) - x_recon = self.predict_start_from_noise(x, t = t, noise = pred_noise) + def p_mean_variance(self, unet, x, t, image_embed, text_encodings = None, lowres_cond_img = None, clip_denoised = True, predict_x0 = False, cond_scale = 1.): + pred = unet.forward_with_cond_scale(x, t, image_embed = image_embed, text_encodings = text_encodings, cond_scale = cond_scale, lowres_cond_img = lowres_cond_img) - if clip_denoised: + if predict_x0: + x_recon = pred + else: + x_recon = self.predict_start_from_noise(x, t = t, noise = pred) + + if clip_denoised and not predict_x0: x_recon.clamp_(-1., 1.) model_mean, posterior_variance, posterior_log_variance = self.q_posterior(x_start=x_recon, x_t=x, t=t) return model_mean, posterior_variance, posterior_log_variance @torch.no_grad() - def p_sample(self, unet, x, t, image_embed, text_encodings = None, cond_scale = 1., lowres_cond_img = None, clip_denoised = True, repeat_noise = False): + def p_sample(self, unet, x, t, image_embed, text_encodings = None, cond_scale = 1., lowres_cond_img = None, predict_x0 = False, clip_denoised = True, repeat_noise = False): b, *_, device = *x.shape, x.device - model_mean, _, model_log_variance = self.p_mean_variance(unet, x = x, t = t, image_embed = image_embed, text_encodings = text_encodings, cond_scale = cond_scale, lowres_cond_img = lowres_cond_img, clip_denoised = clip_denoised) + model_mean, _, model_log_variance = self.p_mean_variance(unet, x = x, t = t, image_embed = image_embed, text_encodings = text_encodings, cond_scale = cond_scale, lowres_cond_img = lowres_cond_img, clip_denoised = clip_denoised, predict_x0 = predict_x0) noise = noise_like(x.shape, device, repeat_noise) # no noise when t == 0 nonzero_mask = (1 - (t == 0).float()).reshape(b, *((1,) * (len(x.shape) - 1))) return model_mean + nonzero_mask * (0.5 * model_log_variance).exp() * noise @torch.no_grad() - def p_sample_loop(self, unet, shape, image_embed, lowres_cond_img = None, text_encodings = None, cond_scale = 1): + def p_sample_loop(self, unet, shape, image_embed, predict_x0 = False, lowres_cond_img = None, text_encodings = None, cond_scale = 1): device = self.betas.device b = shape[0] img = torch.randn(shape, device = device) for i in tqdm(reversed(range(0, self.num_timesteps)), desc = 'sampling loop time step', total = self.num_timesteps): - img = self.p_sample(unet, img, torch.full((b,), i, device = device, dtype = torch.long), image_embed = image_embed, text_encodings = text_encodings, cond_scale = cond_scale, lowres_cond_img = lowres_cond_img) + img = self.p_sample( + unet, + img, + torch.full((b,), i, device = device, dtype = torch.long), + image_embed = image_embed, + text_encodings = text_encodings, + cond_scale = cond_scale, + lowres_cond_img = lowres_cond_img, + predict_x0 = predict_x0 + ) return img @@ -1324,7 +1344,7 @@ class Decoder(nn.Module): extract(self.sqrt_one_minus_alphas_cumprod, t, x_start.shape) * noise ) - def p_losses(self, unet, x_start, t, *, image_embed, lowres_cond_img = None, text_encodings = None, noise = None): + def p_losses(self, unet, x_start, t, *, image_embed, lowres_cond_img = None, text_encodings = None, predict_x0 = False, noise = None): noise = default(noise, lambda: torch.randn_like(x_start)) x_noisy = self.q_sample(x_start = x_start, t = t, noise = noise) @@ -1338,12 +1358,14 @@ class Decoder(nn.Module): cond_drop_prob = self.cond_drop_prob ) + target = noise if not predict_x0 else x_start + if self.loss_type == 'l1': - loss = F.l1_loss(noise, x_recon) + loss = F.l1_loss(target, x_recon) elif self.loss_type == 'l2': - loss = F.mse_loss(noise, x_recon) + loss = F.mse_loss(target, x_recon) elif self.loss_type == "huber": - loss = F.smooth_l1_loss(noise, x_recon) + loss = F.smooth_l1_loss(target, x_recon) else: raise NotImplementedError() @@ -1358,7 +1380,7 @@ class Decoder(nn.Module): img = None - for unet, vae, channel, image_size in tqdm(zip(self.unets, self.vaes, self.sample_channels, self.image_sizes)): + for unet, vae, channel, image_size, predict_x0 in tqdm(zip(self.unets, self.vaes, self.sample_channels, self.image_sizes, self.predict_x0)): with self.one_unet_in_gpu(unet = unet): lowres_cond_img = None shape = (batch_size, channel, image_size, image_size) @@ -1378,6 +1400,7 @@ class Decoder(nn.Module): image_embed = image_embed, text_encodings = text_encodings, cond_scale = cond_scale, + predict_x0 = predict_x0, lowres_cond_img = lowres_cond_img ) @@ -1401,6 +1424,7 @@ class Decoder(nn.Module): target_image_size = self.image_sizes[unet_index] vae = self.vaes[unet_index] + predict_x0 = self.predict_x0[unet_index] b, c, h, w, device, = *image.shape, image.device @@ -1424,7 +1448,7 @@ class Decoder(nn.Module): if exists(lowres_cond_img): lowres_cond_img = vae.encode(lowres_cond_img) - return self.p_losses(unet, image, times, image_embed = image_embed, text_encodings = text_encodings, lowres_cond_img = lowres_cond_img) + return self.p_losses(unet, image, times, image_embed = image_embed, text_encodings = text_encodings, lowres_cond_img = lowres_cond_img, predict_x0 = predict_x0) # main class diff --git a/setup.py b/setup.py index d55db12..bc3cdc7 100644 --- a/setup.py +++ b/setup.py @@ -10,7 +10,7 @@ setup( 'dream = dalle2_pytorch.cli:dream' ], }, - version = '0.0.40', + version = '0.0.41', license='MIT', description = 'DALL-E 2', author = 'Phil Wang',