Delete bit_diffusion.py

bit_diffusion.py

@@ -1,264 +0,0 @@
-from typing import Optional, Tuple, Union
-
-import torch
-from einops import rearrange, reduce
-
-from diffusers import DDIMScheduler, DDPMScheduler, DiffusionPipeline, ImagePipelineOutput, UNet2DConditionModel
-from diffusers.schedulers.scheduling_ddim import DDIMSchedulerOutput
-from diffusers.schedulers.scheduling_ddpm import DDPMSchedulerOutput
-
-
-BITS = 8
-
-
-# convert to bit representations and back taken from https://github.com/lucidrains/bit-diffusion/blob/main/bit_diffusion/bit_diffusion.py
-def decimal_to_bits(x, bits=BITS):
-    """expects image tensor ranging from 0 to 1, outputs bit tensor ranging from -1 to 1"""
-    device = x.device
-
-    x = (x * 255).int().clamp(0, 255)
-
-    mask = 2 ** torch.arange(bits - 1, -1, -1, device=device)
-    mask = rearrange(mask, "d -> d 1 1")
-    x = rearrange(x, "b c h w -> b c 1 h w")
-
-    bits = ((x & mask) != 0).float()
-    bits = rearrange(bits, "b c d h w -> b (c d) h w")
-    bits = bits * 2 - 1
-    return bits
-
-
-def bits_to_decimal(x, bits=BITS):
-    """expects bits from -1 to 1, outputs image tensor from 0 to 1"""
-    device = x.device
-
-    x = (x > 0).int()
-    mask = 2 ** torch.arange(bits - 1, -1, -1, device=device, dtype=torch.int32)
-
-    mask = rearrange(mask, "d -> d 1 1")
-    x = rearrange(x, "b (c d) h w -> b c d h w", d=8)
-    dec = reduce(x * mask, "b c d h w -> b c h w", "sum")
-    return (dec / 255).clamp(0.0, 1.0)
-
-
-# modified scheduler step functions for clamping the predicted x_0 between -bit_scale and +bit_scale
-def ddim_bit_scheduler_step(
-    self,
-    model_output: torch.Tensor,
-    timestep: int,
-    sample: torch.Tensor,
-    eta: float = 0.0,
-    use_clipped_model_output: bool = True,
-    generator=None,
-    return_dict: bool = True,
-) -> Union[DDIMSchedulerOutput, Tuple]:
-    """
-    Predict the sample at the previous timestep by reversing the SDE. Core function to propagate the diffusion
-    process from the learned model outputs (most often the predicted noise).
-    Args:
-        model_output (`torch.Tensor`): direct output from learned diffusion model.
-        timestep (`int`): current discrete timestep in the diffusion chain.
-        sample (`torch.Tensor`):
-            current instance of sample being created by diffusion process.
-        eta (`float`): weight of noise for added noise in diffusion step.
-        use_clipped_model_output (`bool`): TODO
-        generator: random number generator.
-        return_dict (`bool`): option for returning tuple rather than DDIMSchedulerOutput class
-    Returns:
-        [`~schedulers.scheduling_utils.DDIMSchedulerOutput`] or `tuple`:
-        [`~schedulers.scheduling_utils.DDIMSchedulerOutput`] if `return_dict` is True, otherwise a `tuple`. When
-        returning a tuple, the first element is the sample tensor.
-    """
-    if self.num_inference_steps is None:
-        raise ValueError(
-            "Number of inference steps is 'None', you need to run 'set_timesteps' after creating the scheduler"
-        )
-
-    # See formulas (12) and (16) of DDIM paper https://arxiv.org/pdf/2010.02502.pdf
-    # Ideally, read DDIM paper in-detail understanding
-
-    # Notation (<variable name> -> <name in paper>
-    # - pred_noise_t -> e_theta(x_t, t)
-    # - pred_original_sample -> f_theta(x_t, t) or x_0
-    # - std_dev_t -> sigma_t
-    # - eta -> η
-    # - pred_sample_direction -> "direction pointing to x_t"
-    # - pred_prev_sample -> "x_t-1"
-
-    # 1. get previous step value (=t-1)
-    prev_timestep = timestep - self.config.num_train_timesteps // self.num_inference_steps
-
-    # 2. compute alphas, betas
-    alpha_prod_t = self.alphas_cumprod[timestep]
-    alpha_prod_t_prev = self.alphas_cumprod[prev_timestep] if prev_timestep >= 0 else self.final_alpha_cumprod
-
-    beta_prod_t = 1 - alpha_prod_t
-
-    # 3. compute predicted original sample from predicted noise also called
-    # "predicted x_0" of formula (12) from https://arxiv.org/pdf/2010.02502.pdf
-    pred_original_sample = (sample - beta_prod_t ** (0.5) * model_output) / alpha_prod_t ** (0.5)
-
-    # 4. Clip "predicted x_0"
-    scale = self.bit_scale
-    if self.config.clip_sample:
-        pred_original_sample = torch.clamp(pred_original_sample, -scale, scale)
-
-    # 5. compute variance: "sigma_t(η)" -> see formula (16)
-    # σ_t = sqrt((1 − α_t−1)/(1 − α_t)) * sqrt(1 − α_t/α_t−1)
-    variance = self._get_variance(timestep, prev_timestep)
-    std_dev_t = eta * variance ** (0.5)
-
-    if use_clipped_model_output:
-        # the model_output is always re-derived from the clipped x_0 in Glide
-        model_output = (sample - alpha_prod_t ** (0.5) * pred_original_sample) / beta_prod_t ** (0.5)
-
-    # 6. compute "direction pointing to x_t" of formula (12) from https://arxiv.org/pdf/2010.02502.pdf
-    pred_sample_direction = (1 - alpha_prod_t_prev - std_dev_t**2) ** (0.5) * model_output
-
-    # 7. compute x_t without "random noise" of formula (12) from https://arxiv.org/pdf/2010.02502.pdf
-    prev_sample = alpha_prod_t_prev ** (0.5) * pred_original_sample + pred_sample_direction
-
-    if eta > 0:
-        # randn_like does not support generator https://github.com/pytorch/pytorch/issues/27072
-        device = model_output.device if torch.is_tensor(model_output) else "cpu"
-        noise = torch.randn(model_output.shape, dtype=model_output.dtype, generator=generator).to(device)
-        variance = self._get_variance(timestep, prev_timestep) ** (0.5) * eta * noise
-
-        prev_sample = prev_sample + variance
-
-    if not return_dict:
-        return (prev_sample,)
-
-    return DDIMSchedulerOutput(prev_sample=prev_sample, pred_original_sample=pred_original_sample)
-
-
-def ddpm_bit_scheduler_step(
-    self,
-    model_output: torch.Tensor,
-    timestep: int,
-    sample: torch.Tensor,
-    prediction_type="epsilon",
-    generator=None,
-    return_dict: bool = True,
-) -> Union[DDPMSchedulerOutput, Tuple]:
-    """
-    Predict the sample at the previous timestep by reversing the SDE. Core function to propagate the diffusion
-    process from the learned model outputs (most often the predicted noise).
-    Args:
-        model_output (`torch.Tensor`): direct output from learned diffusion model.
-        timestep (`int`): current discrete timestep in the diffusion chain.
-        sample (`torch.Tensor`):
-            current instance of sample being created by diffusion process.
-        prediction_type (`str`, default `epsilon`):
-            indicates whether the model predicts the noise (epsilon), or the samples (`sample`).
-        generator: random number generator.
-        return_dict (`bool`): option for returning tuple rather than DDPMSchedulerOutput class
-    Returns:
-        [`~schedulers.scheduling_utils.DDPMSchedulerOutput`] or `tuple`:
-        [`~schedulers.scheduling_utils.DDPMSchedulerOutput`] if `return_dict` is True, otherwise a `tuple`. When
-        returning a tuple, the first element is the sample tensor.
-    """
-    t = timestep
-
-    if model_output.shape[1] == sample.shape[1] * 2 and self.variance_type in ["learned", "learned_range"]:
-        model_output, predicted_variance = torch.split(model_output, sample.shape[1], dim=1)
-    else:
-        predicted_variance = None
-
-    # 1. compute alphas, betas
-    alpha_prod_t = self.alphas_cumprod[t]
-    alpha_prod_t_prev = self.alphas_cumprod[t - 1] if t > 0 else self.one
-    beta_prod_t = 1 - alpha_prod_t
-    beta_prod_t_prev = 1 - alpha_prod_t_prev
-
-    # 2. compute predicted original sample from predicted noise also called
-    # "predicted x_0" of formula (15) from https://arxiv.org/pdf/2006.11239.pdf
-    if prediction_type == "epsilon":
-        pred_original_sample = (sample - beta_prod_t ** (0.5) * model_output) / alpha_prod_t ** (0.5)
-    elif prediction_type == "sample":
-        pred_original_sample = model_output
-    else:
-        raise ValueError(f"Unsupported prediction_type {prediction_type}.")
-
-    # 3. Clip "predicted x_0"
-    scale = self.bit_scale
-    if self.config.clip_sample:
-        pred_original_sample = torch.clamp(pred_original_sample, -scale, scale)
-
-    # 4. Compute coefficients for pred_original_sample x_0 and current sample x_t
-    # See formula (7) from https://arxiv.org/pdf/2006.11239.pdf
-    pred_original_sample_coeff = (alpha_prod_t_prev ** (0.5) * self.betas[t]) / beta_prod_t
-    current_sample_coeff = self.alphas[t] ** (0.5) * beta_prod_t_prev / beta_prod_t
-
-    # 5. Compute predicted previous sample µ_t
-    # See formula (7) from https://arxiv.org/pdf/2006.11239.pdf
-    pred_prev_sample = pred_original_sample_coeff * pred_original_sample + current_sample_coeff * sample
-
-    # 6. Add noise
-    variance = 0
-    if t > 0:
-        noise = torch.randn(
-            model_output.size(), dtype=model_output.dtype, layout=model_output.layout, generator=generator
-        ).to(model_output.device)
-        variance = (self._get_variance(t, predicted_variance=predicted_variance) ** 0.5) * noise
-
-    pred_prev_sample = pred_prev_sample + variance
-
-    if not return_dict:
-        return (pred_prev_sample,)
-
-    return DDPMSchedulerOutput(prev_sample=pred_prev_sample, pred_original_sample=pred_original_sample)
-
-
-class BitDiffusion(DiffusionPipeline):
-    def __init__(
-        self,
-        unet: UNet2DConditionModel,
-        scheduler: Union[DDIMScheduler, DDPMScheduler],
-        bit_scale: Optional[float] = 1.0,
-    ):
-        super().__init__()
-        self.bit_scale = bit_scale
-        self.scheduler.step = (
-            ddim_bit_scheduler_step if isinstance(scheduler, DDIMScheduler) else ddpm_bit_scheduler_step
-        )
-
-        self.register_modules(unet=unet, scheduler=scheduler)
-
-    @torch.no_grad()
-    def __call__(
-        self,
-        height: Optional[int] = 256,
-        width: Optional[int] = 256,
-        num_inference_steps: Optional[int] = 50,
-        generator: Optional[torch.Generator] = None,
-        batch_size: Optional[int] = 1,
-        output_type: Optional[str] = "pil",
-        return_dict: bool = True,
-        **kwargs,
-    ) -> Union[Tuple, ImagePipelineOutput]:
-        latents = torch.randn(
-            (batch_size, self.unet.config.in_channels, height, width),
-            generator=generator,
-        )
-        latents = decimal_to_bits(latents) * self.bit_scale
-        latents = latents.to(self.device)
-
-        self.scheduler.set_timesteps(num_inference_steps)
-
-        for t in self.progress_bar(self.scheduler.timesteps):
-            # predict the noise residual
-            noise_pred = self.unet(latents, t).sample
-
-            # compute the previous noisy sample x_t -> x_t-1
-            latents = self.scheduler.step(noise_pred, t, latents).prev_sample
-
-        image = bits_to_decimal(latents)
-
-        if output_type == "pil":
-            image = self.numpy_to_pil(image)
-
-        if not return_dict:
-            return (image,)
-
-        return ImagePipelineOutput(images=image)