add fine tuning FLUX.1 (WIP)

library/flux_train_utils.py

@@ -12,8 +12,9 @@ from accelerate import Accelerator, PartialState
 from transformers import CLIPTextModel
 from tqdm import tqdm
 from PIL import Image
+from safetensors.torch import save_file
 
-from library import flux_models, flux_utils, strategy_base
+from library import flux_models, flux_utils, strategy_base, train_util
 from library.sd3_train_utils import load_prompts
 from library.device_utils import init_ipex, clean_memory_on_device
 
@@ -27,6 +28,9 @@ import logging
 logger = logging.getLogger(__name__)
 
 
+# region sample images
+
+
 def sample_images(
     accelerator: Accelerator,
     args: argparse.Namespace,
@@ -295,3 +299,267 @@ def denoise(
         img = img + (t_prev - t_curr) * pred
 
     return img
+
+
+# endregion
+
+
+# region train
+def get_sigmas(noise_scheduler, timesteps, device, n_dim=4, dtype=torch.float32):
+    sigmas = noise_scheduler.sigmas.to(device=device, dtype=dtype)
+    schedule_timesteps = noise_scheduler.timesteps.to(device)
+    timesteps = timesteps.to(device)
+    step_indices = [(schedule_timesteps == t).nonzero().item() for t in timesteps]
+
+    sigma = sigmas[step_indices].flatten()
+    while len(sigma.shape) < n_dim:
+        sigma = sigma.unsqueeze(-1)
+    return sigma
+
+
+def compute_density_for_timestep_sampling(
+    weighting_scheme: str, batch_size: int, logit_mean: float = None, logit_std: float = None, mode_scale: float = None
+):
+    """Compute the density for sampling the timesteps when doing SD3 training.
+
+    Courtesy: This was contributed by Rafie Walker in https://github.com/huggingface/diffusers/pull/8528.
+
+    SD3 paper reference: https://arxiv.org/abs/2403.03206v1.
+    """
+    if weighting_scheme == "logit_normal":
+        # See 3.1 in the SD3 paper ($rf/lognorm(0.00,1.00)$).
+        u = torch.normal(mean=logit_mean, std=logit_std, size=(batch_size,), device="cpu")
+        u = torch.nn.functional.sigmoid(u)
+    elif weighting_scheme == "mode":
+        u = torch.rand(size=(batch_size,), device="cpu")
+        u = 1 - u - mode_scale * (torch.cos(math.pi * u / 2) ** 2 - 1 + u)
+    else:
+        u = torch.rand(size=(batch_size,), device="cpu")
+    return u
+
+
+def compute_loss_weighting_for_sd3(weighting_scheme: str, sigmas=None):
+    """Computes loss weighting scheme for SD3 training.
+
+    Courtesy: This was contributed by Rafie Walker in https://github.com/huggingface/diffusers/pull/8528.
+
+    SD3 paper reference: https://arxiv.org/abs/2403.03206v1.
+    """
+    if weighting_scheme == "sigma_sqrt":
+        weighting = (sigmas**-2.0).float()
+    elif weighting_scheme == "cosmap":
+        bot = 1 - 2 * sigmas + 2 * sigmas**2
+        weighting = 2 / (math.pi * bot)
+    else:
+        weighting = torch.ones_like(sigmas)
+    return weighting
+
+
+def get_noisy_model_input_and_timesteps(
+    args, noise_scheduler, latents, noise, device, dtype
+) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
+    bsz = latents.shape[0]
+    sigmas = None
+
+    if args.timestep_sampling == "uniform" or args.timestep_sampling == "sigmoid":
+        # Simple random t-based noise sampling
+        if args.timestep_sampling == "sigmoid":
+            # https://github.com/XLabs-AI/x-flux/tree/main
+            t = torch.sigmoid(args.sigmoid_scale * torch.randn((bsz,), device=device))
+        else:
+            t = torch.rand((bsz,), device=device)
+        timesteps = t * 1000.0
+        t = t.view(-1, 1, 1, 1)
+        noisy_model_input = (1 - t) * latents + t * noise
+    else:
+        # Sample a random timestep for each image
+        # for weighting schemes where we sample timesteps non-uniformly
+        u = compute_density_for_timestep_sampling(
+            weighting_scheme=args.weighting_scheme,
+            batch_size=bsz,
+            logit_mean=args.logit_mean,
+            logit_std=args.logit_std,
+            mode_scale=args.mode_scale,
+        )
+        indices = (u * noise_scheduler.config.num_train_timesteps).long()
+        timesteps = noise_scheduler.timesteps[indices].to(device=device)
+
+        # Add noise according to flow matching.
+        sigmas = get_sigmas(noise_scheduler, timesteps, device, n_dim=latents.ndim, dtype=dtype)
+        noisy_model_input = sigmas * noise + (1.0 - sigmas) * latents
+
+    return noisy_model_input, timesteps, sigmas
+
+
+def apply_model_prediction_type(args, model_pred, noisy_model_input, sigmas):
+    weighting = None
+    if args.model_prediction_type == "raw":
+        pass
+    elif args.model_prediction_type == "additive":
+        # add the model_pred to the noisy_model_input
+        model_pred = model_pred + noisy_model_input
+    elif args.model_prediction_type == "sigma_scaled":
+        # apply sigma scaling
+        model_pred = model_pred * (-sigmas) + noisy_model_input
+
+        # these weighting schemes use a uniform timestep sampling
+        # and instead post-weight the loss
+        weighting = compute_loss_weighting_for_sd3(weighting_scheme=args.weighting_scheme, sigmas=sigmas)
+
+    return model_pred, weighting
+
+
+def save_models(ckpt_path: str, flux: flux_models.Flux, sai_metadata: Optional[dict], save_dtype: Optional[torch.dtype] = None):
+    state_dict = {}
+
+    def update_sd(prefix, sd):
+        for k, v in sd.items():
+            key = prefix + k
+            if save_dtype is not None:
+                v = v.detach().clone().to("cpu").to(save_dtype)
+            state_dict[key] = v
+
+    update_sd("", flux.state_dict())
+
+    save_file(state_dict, ckpt_path, metadata=sai_metadata)
+
+
+def save_flux_model_on_train_end(
+    args: argparse.Namespace, save_dtype: torch.dtype, epoch: int, global_step: int, flux: flux_models.Flux
+):
+    def sd_saver(ckpt_file, epoch_no, global_step):
+        sai_metadata = train_util.get_sai_model_spec(None, args, False, False, False, is_stable_diffusion_ckpt=True, flux="dev")
+        save_models(ckpt_file, flux, sai_metadata, save_dtype)
+
+    train_util.save_sd_model_on_train_end_common(args, True, True, epoch, global_step, sd_saver, None)
+
+
+# epochとstepの保存、メタデータにepoch/stepが含まれ引数が同じになるため、統合している
+# on_epoch_end: Trueならepoch終了時、Falseならstep経過時
+def save_flux_model_on_epoch_end_or_stepwise(
+    args: argparse.Namespace,
+    on_epoch_end: bool,
+    accelerator,
+    save_dtype: torch.dtype,
+    epoch: int,
+    num_train_epochs: int,
+    global_step: int,
+    flux: flux_models.Flux,
+):
+    def sd_saver(ckpt_file, epoch_no, global_step):
+        sai_metadata = train_util.get_sai_model_spec(None, args, False, False, False, is_stable_diffusion_ckpt=True, flux="dev")
+        save_models(ckpt_file, flux, sai_metadata, save_dtype)
+
+    train_util.save_sd_model_on_epoch_end_or_stepwise_common(
+        args,
+        on_epoch_end,
+        accelerator,
+        True,
+        True,
+        epoch,
+        num_train_epochs,
+        global_step,
+        sd_saver,
+        None,
+    )
+
+
+# endregion
+
+
+def add_flux_train_arguments(parser: argparse.ArgumentParser):
+    parser.add_argument(
+        "--clip_l",
+        type=str,
+        help="path to clip_l (*.sft or *.safetensors), should be float16 / clip_lのパス（*.sftまたは*.safetensors）、float16が前提",
+    )
+    parser.add_argument(
+        "--t5xxl",
+        type=str,
+        help="path to t5xxl (*.sft or *.safetensors), should be float16 / t5xxlのパス（*.sftまたは*.safetensors）、float16が前提",
+    )
+    parser.add_argument("--ae", type=str, help="path to ae (*.sft or *.safetensors) / aeのパス（*.sftまたは*.safetensors）")
+    parser.add_argument(
+        "--t5xxl_max_token_length",
+        type=int,
+        default=None,
+        help="maximum token length for T5-XXL. if omitted, 256 for schnell and 512 for dev"
+        " / T5-XXLの最大トークン長。省略された場合、schnellの場合は256、devの場合は512",
+    )
+    parser.add_argument(
+        "--apply_t5_attn_mask",
+        action="store_true",
+        help="apply attention mask (zero embs) to T5-XXL / T5-XXLにアテンションマスク（ゼロ埋め）を適用する",
+    )
+    parser.add_argument(
+        "--cache_text_encoder_outputs", action="store_true", help="cache text encoder outputs / text encoderの出力をキャッシュする"
+    )
+    parser.add_argument(
+        "--cache_text_encoder_outputs_to_disk",
+        action="store_true",
+        help="cache text encoder outputs to disk / text encoderの出力をディスクにキャッシュする",
+    )
+    parser.add_argument(
+        "--text_encoder_batch_size",
+        type=int,
+        default=None,
+        help="text encoder batch size (default: None, use dataset's batch size)"
+        + " / text encoderのバッチサイズ（デフォルト: None, データセットのバッチサイズを使用）",
+    )
+    parser.add_argument(
+        "--disable_mmap_load_safetensors",
+        action="store_true",
+        help="disable mmap load for safetensors. Speed up model loading in WSL environment / safetensorsのmmapロードを無効にする。WSL環境等でモデル読み込みを高速化できる",
+    )
+
+    # copy from Diffusers
+    parser.add_argument(
+        "--weighting_scheme",
+        type=str,
+        default="none",
+        choices=["sigma_sqrt", "logit_normal", "mode", "cosmap", "none"],
+    )
+    parser.add_argument(
+        "--logit_mean", type=float, default=0.0, help="mean to use when using the `'logit_normal'` weighting scheme."
+    )
+    parser.add_argument("--logit_std", type=float, default=1.0, help="std to use when using the `'logit_normal'` weighting scheme.")
+    parser.add_argument(
+        "--mode_scale",
+        type=float,
+        default=1.29,
+        help="Scale of mode weighting scheme. Only effective when using the `'mode'` as the `weighting_scheme`.",
+    )
+    parser.add_argument(
+        "--guidance_scale",
+        type=float,
+        default=3.5,
+        help="the FLUX.1 dev variant is a guidance distilled model",
+    )
+
+    parser.add_argument(
+        "--timestep_sampling",
+        choices=["sigma", "uniform", "sigmoid"],
+        default="sigma",
+        help="Method to sample timesteps: sigma-based, uniform random, or sigmoid of random normal. / タイムステップをサンプリングする方法：sigma、random uniform、またはrandom normalのsigmoid。",
+    )
+    parser.add_argument(
+        "--sigmoid_scale",
+        type=float,
+        default=1.0,
+        help='Scale factor for sigmoid timestep sampling (only used when timestep-sampling is "sigmoid"). / sigmoidタイムステップサンプリングの倍率（timestep-samplingが"sigmoid"の場合のみ有効）。',
+    )
+    parser.add_argument(
+        "--model_prediction_type",
+        choices=["raw", "additive", "sigma_scaled"],
+        default="sigma_scaled",
+        help="How to interpret and process the model prediction: "
+        "raw (use as is), additive (add to noisy input), sigma_scaled (apply sigma scaling)."
+        " / モデル予測の解釈と処理方法："
+        "raw（そのまま使用）、additive（ノイズ入力に加算）、sigma_scaled（シグマスケーリングを適用）。",
+    )
+    parser.add_argument(
+        "--discrete_flow_shift",
+        type=float,
+        default=3.0,
+        help="Discrete flow shift for the Euler Discrete Scheduler, default is 3.0. / Euler Discrete Schedulerの離散フローシフト、デフォルトは3.0。",
+    )

library/train_util.py

@@ -2629,7 +2629,7 @@ class MinimalDataset(BaseDataset):
         raise NotImplementedError
 
 
-def load_arbitrary_dataset(args, tokenizer) -> MinimalDataset:
+def load_arbitrary_dataset(args, tokenizer=None) -> MinimalDataset:
     module = ".".join(args.dataset_class.split(".")[:-1])
     dataset_class = args.dataset_class.split(".")[-1]
     module = importlib.import_module(module)