From 18f2372ffbd101f0d554fd2c0f73723a94bc9c2b Mon Sep 17 00:00:00 2001
From: huiwenshi <Huiwenshi@users.noreply.huggingface.co>
Date: Sat, 14 Jun 2025 06:29:24 +0000
Subject: [PATCH] Upload hunyuan3d-paintpbr-v2-1/model.py with huggingface_hub

---
 hunyuan3d-paintpbr-v2-1/model.py | 622 +++++++++++++++++++++++++++++++
 1 file changed, 622 insertions(+)
 create mode 100644 hunyuan3d-paintpbr-v2-1/model.py

diff --git a/hunyuan3d-paintpbr-v2-1/model.py b/hunyuan3d-paintpbr-v2-1/model.py
new file mode 100644
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+# Hunyuan 3D is licensed under the TENCENT HUNYUAN NON-COMMERCIAL LICENSE AGREEMENT
+# except for the third-party components listed below.
+# Hunyuan 3D does not impose any additional limitations beyond what is outlined
+# in the repsective licenses of these third-party components.
+# Users must comply with all terms and conditions of original licenses of these third-party
+# components and must ensure that the usage of the third party components adheres to
+# all relevant laws and regulations.
+
+# For avoidance of doubts, Hunyuan 3D means the large language models and
+# their software and algorithms, including trained model weights, parameters (including
+# optimizer states), machine-learning model code, inference-enabling code, training-enabling code,
+# fine-tuning enabling code and other elements of the foregoing made publicly available
+# by Tencent in accordance with TENCENT HUNYUAN COMMUNITY LICENSE AGREEMENT.
+
+import os
+
+# import ipdb
+import numpy as np
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+import pytorch_lightning as pl
+from tqdm import tqdm
+from torchvision.transforms import v2
+from torchvision.utils import make_grid, save_image
+from einops import rearrange
+
+from diffusers import (
+    DiffusionPipeline,
+    EulerAncestralDiscreteScheduler,
+    DDPMScheduler,
+    UNet2DConditionModel,
+    ControlNetModel,
+)
+
+from .modules import Dino_v2, UNet2p5DConditionModel
+import math
+
+
+def extract_into_tensor(a, t, x_shape):
+    b, *_ = t.shape
+    out = a.gather(-1, t)
+    return out.reshape(b, *((1,) * (len(x_shape) - 1)))
+
+
+class HunyuanPaint(pl.LightningModule):
+    def __init__(
+        self,
+        stable_diffusion_config,
+        control_net_config=None,
+        num_view=6,
+        view_size=320,
+        drop_cond_prob=0.1,
+        with_normal_map=None,
+        with_position_map=None,
+        pbr_settings=["albedo", "mr"],
+        **kwargs,
+    ):
+        """Initializes the HunyuanPaint Lightning Module.
+
+        Args:
+            stable_diffusion_config: Configuration for loading the Stable Diffusion pipeline
+            control_net_config: Configuration for ControlNet (optional)
+            num_view: Number of views to process
+            view_size: Size of input views (height/width)
+            drop_cond_prob: Probability of dropping conditioning input during training
+            with_normal_map: Flag indicating whether normal maps are used
+            with_position_map: Flag indicating whether position maps are used
+            pbr_settings: List of PBR materials to generate (e.g., albedo, metallic-roughness)
+            **kwargs: Additional keyword arguments
+        """
+        super(HunyuanPaint, self).__init__()
+
+        self.num_view = num_view
+        self.view_size = view_size
+        self.drop_cond_prob = drop_cond_prob
+        self.pbr_settings = pbr_settings
+
+        # init modules
+        pipeline = DiffusionPipeline.from_pretrained(**stable_diffusion_config)
+        pipeline.set_pbr_settings(self.pbr_settings)
+        pipeline.scheduler = EulerAncestralDiscreteScheduler.from_config(
+            pipeline.scheduler.config, timestep_spacing="trailing"
+        )
+
+        self.with_normal_map = with_normal_map
+        self.with_position_map = with_position_map
+
+        self.pipeline = pipeline
+
+        self.pipeline.vae.use_slicing = True
+
+        train_sched = DDPMScheduler.from_config(self.pipeline.scheduler.config)
+
+        if isinstance(self.pipeline.unet, UNet2DConditionModel):
+            self.pipeline.unet = UNet2p5DConditionModel(
+                self.pipeline.unet, train_sched, self.pipeline.scheduler, self.pbr_settings
+            )
+        self.train_scheduler = train_sched  # use ddpm scheduler during training
+
+        self.register_schedule()
+
+        pipeline.set_learned_parameters()
+
+        if control_net_config is not None:
+            pipeline.unet = pipeline.unet.bfloat16().requires_grad_(control_net_config.train_unet)
+            self.pipeline.add_controlnet(
+                ControlNetModel.from_pretrained(control_net_config.pretrained_model_name_or_path),
+                conditioning_scale=0.75,
+            )
+
+        self.unet = pipeline.unet
+
+        self.pipeline.set_progress_bar_config(disable=True)
+        self.pipeline.vae = self.pipeline.vae.bfloat16()
+        self.pipeline.text_encoder = self.pipeline.text_encoder.bfloat16()
+
+        if self.unet.use_dino:
+            self.dino_v2 = Dino_v2("facebook/dinov2-giant")
+            self.dino_v2 = self.dino_v2.bfloat16()
+
+        self.validation_step_outputs = []
+
+    def register_schedule(self):
+
+        self.num_timesteps = self.train_scheduler.config.num_train_timesteps
+
+        betas = self.train_scheduler.betas.detach().cpu()
+
+        alphas = 1.0 - betas
+        alphas_cumprod = torch.cumprod(alphas, dim=0)
+        alphas_cumprod_prev = torch.cat([torch.ones(1, dtype=torch.float64), alphas_cumprod[:-1]], 0)
+
+        self.register_buffer("betas", betas.float())
+        self.register_buffer("alphas_cumprod", alphas_cumprod.float())
+        self.register_buffer("alphas_cumprod_prev", alphas_cumprod_prev.float())
+
+        # calculations for diffusion q(x_t | x_{t-1}) and others
+        self.register_buffer("sqrt_alphas_cumprod", torch.sqrt(alphas_cumprod).float())
+        self.register_buffer("sqrt_one_minus_alphas_cumprod", torch.sqrt(1 - alphas_cumprod).float())
+
+        self.register_buffer("sqrt_recip_alphas_cumprod", torch.sqrt(1.0 / alphas_cumprod).float())
+        self.register_buffer("sqrt_recipm1_alphas_cumprod", torch.sqrt(1.0 / alphas_cumprod - 1).float())
+
+    def on_fit_start(self):
+        device = torch.device(f"cuda:{self.local_rank}")
+        self.pipeline.to(device)
+        if self.global_rank == 0:
+            os.makedirs(os.path.join(self.logdir, "images_val"), exist_ok=True)
+
+    def prepare_batch_data(self, batch):
+        """Preprocesses a batch of input data for training/inference.
+
+        Args:
+            batch: Raw input batch dictionary
+
+        Returns:
+            tuple: Contains:
+                - cond_imgs: Primary conditioning images (B, 1, C, H, W)
+                - cond_imgs_another: Secondary conditioning images (B, 1, C, H, W)
+                - target_imgs: Dictionary of target PBR images resized and clamped
+                - images_normal: Preprocessed normal maps (if available)
+                - images_position: Preprocessed position maps (if available)
+        """
+
+        images_cond = batch["images_cond"].to(self.device)  # (B, M, C, H, W), where M is the number of reference images
+        cond_imgs, cond_imgs_another = images_cond[:, 0:1, ...], images_cond[:, 1:2, ...]
+
+        cond_size = self.view_size
+        cond_imgs = v2.functional.resize(cond_imgs, cond_size, interpolation=3, antialias=True).clamp(0, 1)
+        cond_imgs_another = v2.functional.resize(cond_imgs_another, cond_size, interpolation=3, antialias=True).clamp(
+            0, 1
+        )
+
+        target_imgs = {}
+        for pbr_token in self.pbr_settings:
+            target_imgs[pbr_token] = batch[f"images_{pbr_token}"].to(self.device)
+            target_imgs[pbr_token] = v2.functional.resize(
+                target_imgs[pbr_token], self.view_size, interpolation=3, antialias=True
+            ).clamp(0, 1)
+
+        images_normal = None
+        if "images_normal" in batch:
+            images_normal = batch["images_normal"]  # (B, N, C, H, W)
+            images_normal = v2.functional.resize(images_normal, self.view_size, interpolation=3, antialias=True).clamp(
+                0, 1
+            )
+            images_normal = [images_normal]
+
+        images_position = None
+        if "images_position" in batch:
+            images_position = batch["images_position"]  # (B, N, C, H, W)
+            images_position = v2.functional.resize(
+                images_position, self.view_size, interpolation=3, antialias=True
+            ).clamp(0, 1)
+            images_position = [images_position]
+
+        return cond_imgs, cond_imgs_another, target_imgs, images_normal, images_position
+
+    @torch.no_grad()
+    def forward_text_encoder(self, prompts):
+        device = next(self.pipeline.vae.parameters()).device
+        text_embeds = self.pipeline.encode_prompt(prompts, device, 1, False)[0]
+        return text_embeds
+
+    @torch.no_grad()
+    def encode_images(self, images):
+        """Encodes input images into latent representations using the VAE.
+
+        Handles both standard input (B, N, C, H, W) and PBR input (B, N_pbrs, N, C, H, W)
+        Maintains original batch structure in output latents.
+
+        Args:
+            images: Input images tensor
+
+        Returns:
+            torch.Tensor: Latent representations with original batch dimensions preserved
+        """
+
+        B = images.shape[0]
+        image_ndims = images.ndim
+        if image_ndims != 5:
+            N_pbrs, N = images.shape[1:3]
+        images = (
+            rearrange(images, "b n c h w -> (b n) c h w")
+            if image_ndims == 5
+            else rearrange(images, "b n_pbrs n c h w -> (b n_pbrs n) c h w")
+        )
+        dtype = next(self.pipeline.vae.parameters()).dtype
+
+        images = (images - 0.5) * 2.0
+        posterior = self.pipeline.vae.encode(images.to(dtype)).latent_dist
+        latents = posterior.sample() * self.pipeline.vae.config.scaling_factor
+
+        latents = (
+            rearrange(latents, "(b n) c h w -> b n c h w", b=B)
+            if image_ndims == 5
+            else rearrange(latents, "(b n_pbrs n) c h w -> b n_pbrs n c h w", b=B, n_pbrs=N_pbrs)
+        )
+
+        return latents
+
+    def forward_unet(self, latents, t, **cached_condition):
+        """Runs the UNet model to predict noise/latent residuals.
+
+        Args:
+            latents: Noisy latent representations (B, C, H, W)
+            t: Timestep tensor (B,)
+            **cached_condition: Dictionary of conditioning inputs (text embeds, reference images, etc)
+
+        Returns:
+            torch.Tensor: UNet output (predicted noise or velocity)
+        """
+
+        dtype = next(self.unet.parameters()).dtype
+        latents = latents.to(dtype)
+        shading_embeds = cached_condition["shading_embeds"]
+        pred_noise = self.pipeline.unet(latents, t, encoder_hidden_states=shading_embeds, **cached_condition)
+        return pred_noise[0]
+
+    def predict_start_from_z_and_v(self, x_t, t, v):
+        """
+        Predicts clean image (x0) from noisy latents (x_t) and
+        velocity prediction (v) using the v-prediction formula.
+
+        Args:
+            x_t: Noisy latents at timestep t
+            t: Current timestep
+            v: Predicted velocity (v) from UNet
+
+        Returns:
+            torch.Tensor: Predicted clean image (x0)
+        """
+
+        return (
+            extract_into_tensor(self.sqrt_alphas_cumprod, t, x_t.shape) * x_t
+            - extract_into_tensor(self.sqrt_one_minus_alphas_cumprod, t, x_t.shape) * v
+        )
+
+    def get_v(self, x, noise, t):
+        """Computes the target velocity (v) for v-prediction training.
+
+        Args:
+            x: Clean latents (x0)
+            noise: Added noise
+            t: Current timestep
+
+        Returns:
+            torch.Tensor: Target velocity
+        """
+
+        return (
+            extract_into_tensor(self.sqrt_alphas_cumprod, t, x.shape) * noise
+            - extract_into_tensor(self.sqrt_one_minus_alphas_cumprod, t, x.shape) * x
+        )
+
+    def training_step(self, batch, batch_idx):
+        """Performs a single training step with both conditioning paths.
+
+        Implements:
+        1. Dual-conditioning path training (main ref + secondary ref)
+        2. Velocity-prediction with consistency loss
+        3. Conditional dropout for robust learning
+        4. PBR-specific losses (albedo/metallic-roughness)
+
+        Args:
+            batch: Input batch from dataloader
+            batch_idx: Index of current batch
+
+        Returns:
+            torch.Tensor: Combined loss value
+        """
+
+        cond_imgs, cond_imgs_another, target_imgs, normal_imgs, position_imgs = self.prepare_batch_data(batch)
+
+        B, N_ref = cond_imgs.shape[:2]
+        _, N_gen, _, H, W = target_imgs["albedo"].shape
+        N_pbrs = len(self.pbr_settings)
+        t = torch.randint(0, self.num_timesteps, size=(B,)).long().to(self.device)
+        t = t.unsqueeze(-1).repeat(1, N_pbrs, N_gen)
+        t = rearrange(t, "b n_pbrs n -> (b n_pbrs n)")
+
+        all_target_pbrs = []
+        for pbr_token in self.pbr_settings:
+            all_target_pbrs.append(target_imgs[pbr_token])
+        all_target_pbrs = torch.stack(all_target_pbrs, dim=0).transpose(1, 0)
+        gen_latents = self.encode_images(all_target_pbrs)  #! B, N_pbrs N C H W
+        ref_latents = self.encode_images(cond_imgs)  #! B, M, C, H, W
+        ref_latents_another = self.encode_images(cond_imgs_another)  #! B, M, C, H, W
+
+        all_shading_tokens = []
+        for token in self.pbr_settings:
+            if token in ["albedo", "mr"]:
+                all_shading_tokens.append(
+                    getattr(self.unet, f"learned_text_clip_{token}").unsqueeze(dim=0).repeat(B, 1, 1)
+                )
+        shading_embeds = torch.stack(all_shading_tokens, dim=1)
+
+        if self.unet.use_dino:
+            dino_hidden_states = self.dino_v2(cond_imgs[:, :1, ...])
+            dino_hidden_states_another = self.dino_v2(cond_imgs_another[:, :1, ...])
+
+        gen_latents = rearrange(gen_latents, "b n_pbrs n c h w -> (b n_pbrs n) c h w")
+        noise = torch.randn_like(gen_latents).to(self.device)
+        latents_noisy = self.train_scheduler.add_noise(gen_latents, noise, t).to(self.device)
+        latents_noisy = rearrange(latents_noisy, "(b n_pbrs n) c h w -> b n_pbrs n c h w", b=B, n_pbrs=N_pbrs)
+
+        cached_condition = {}
+
+        if normal_imgs is not None:
+            normal_embeds = self.encode_images(normal_imgs[0])
+            cached_condition["embeds_normal"] = normal_embeds  #! B, N, C, H, W
+
+        if position_imgs is not None:
+            position_embeds = self.encode_images(position_imgs[0])
+            cached_condition["embeds_position"] = position_embeds  #! B, N, C, H, W
+            cached_condition["position_maps"] = position_imgs[0]  #! B, N, C, H, W
+
+        for b in range(B):
+            prob = np.random.rand()
+            if prob < self.drop_cond_prob:
+                if "normal_imgs" in cached_condition:
+                    cached_condition["embeds_normal"][b, ...] = torch.zeros_like(
+                        cached_condition["embeds_normal"][b, ...]
+                    )
+                if "position_imgs" in cached_condition:
+                    cached_condition["embeds_position"][b, ...] = torch.zeros_like(
+                        cached_condition["embeds_position"][b, ...]
+                    )
+
+            prob = np.random.rand()
+            if prob < self.drop_cond_prob:
+                if "position_maps" in cached_condition:
+                    cached_condition["position_maps"][b, ...] = torch.zeros_like(
+                        cached_condition["position_maps"][b, ...]
+                    )
+
+            prob = np.random.rand()
+            if prob < self.drop_cond_prob:
+                dino_hidden_states[b, ...] = torch.zeros_like(dino_hidden_states[b, ...])
+            prob = np.random.rand()
+            if prob < self.drop_cond_prob:
+                dino_hidden_states_another[b, ...] = torch.zeros_like(dino_hidden_states_another[b, ...])
+
+        # MVA & Ref Attention
+        prob = np.random.rand()
+        cached_condition["mva_scale"] = 1.0
+        cached_condition["ref_scale"] = 1.0
+        if prob < self.drop_cond_prob:
+            cached_condition["mva_scale"] = 0.0
+            cached_condition["ref_scale"] = 0.0
+        elif prob > 1.0 - self.drop_cond_prob:
+            prob = np.random.rand()
+            if prob < 0.5:
+                cached_condition["mva_scale"] = 0.0
+            else:
+                cached_condition["ref_scale"] = 0.0
+        else:
+            pass
+
+        if self.train_scheduler.config.prediction_type == "v_prediction":
+
+            cached_condition["shading_embeds"] = shading_embeds
+            cached_condition["ref_latents"] = ref_latents
+            cached_condition["dino_hidden_states"] = dino_hidden_states
+            v_pred = self.forward_unet(latents_noisy, t, **cached_condition)
+            v_pred_albedo, v_pred_mr = torch.split(
+                rearrange(
+                    v_pred, "(b n_pbr n) c h w -> b n_pbr n c h w", n_pbr=len(self.pbr_settings), n=self.num_view
+                ),
+                1,
+                dim=1,
+            )
+            v_target = self.get_v(gen_latents, noise, t)
+            v_target_albedo, v_target_mr = torch.split(
+                rearrange(
+                    v_target, "(b n_pbr n) c h w -> b n_pbr n c h w", n_pbr=len(self.pbr_settings), n=self.num_view
+                ),
+                1,
+                dim=1,
+            )
+
+            albedo_loss_1, _ = self.compute_loss(v_pred_albedo, v_target_albedo)
+            mr_loss_1, _ = self.compute_loss(v_pred_mr, v_target_mr)
+
+            cached_condition["ref_latents"] = ref_latents_another
+            cached_condition["dino_hidden_states"] = dino_hidden_states_another
+            v_pred_another = self.forward_unet(latents_noisy, t, **cached_condition)
+            v_pred_another_albedo, v_pred_another_mr = torch.split(
+                rearrange(
+                    v_pred_another,
+                    "(b n_pbr n) c h w -> b n_pbr n c h w",
+                    n_pbr=len(self.pbr_settings),
+                    n=self.num_view,
+                ),
+                1,
+                dim=1,
+            )
+
+            albedo_loss_2, _ = self.compute_loss(v_pred_another_albedo, v_target_albedo)
+            mr_loss_2, _ = self.compute_loss(v_pred_another_mr, v_target_mr)
+
+            consistency_loss, _ = self.compute_loss(v_pred_another, v_pred)
+
+            albedo_loss = (albedo_loss_1 + albedo_loss_2) * 0.5
+            mr_loss = (mr_loss_1 + mr_loss_2) * 0.5
+
+            log_loss_dict = {}
+            log_loss_dict.update({f"train/albedo_loss": albedo_loss})
+            log_loss_dict.update({f"train/mr_loss": mr_loss})
+            log_loss_dict.update({f"train/cons_loss": consistency_loss})
+
+            loss_dict = log_loss_dict
+
+        elif self.train_scheduler.config.prediction_type == "epsilon":
+            e_pred = self.forward_unet(latents_noisy, t, **cached_condition)
+            loss, loss_dict = self.compute_loss(e_pred, noise)
+        else:
+            raise f"No {self.train_scheduler.config.prediction_type}"
+
+        # logging
+        self.log_dict(loss_dict, prog_bar=True, logger=True, on_step=True, on_epoch=True)
+        self.log("global_step", self.global_step, prog_bar=True, logger=True, on_step=True, on_epoch=False)
+        lr = self.optimizers().param_groups[0]["lr"]
+        self.log("lr_abs", lr, prog_bar=True, logger=True, on_step=True, on_epoch=False)
+
+        return 0.85 * (albedo_loss + mr_loss) + 0.15 * consistency_loss
+
+    def compute_loss(self, noise_pred, noise_gt):
+        loss = F.mse_loss(noise_pred, noise_gt)
+        prefix = "train"
+        loss_dict = {}
+        loss_dict.update({f"{prefix}/loss": loss})
+        return loss, loss_dict
+
+    @torch.no_grad()
+    def validation_step(self, batch, batch_idx):
+        """Performs validation on a single batch.
+
+        Generates predicted images using:
+        1. Reference conditioning images
+        2. Optional normal/position maps
+        3. Frozen DINO features (if enabled)
+        4. Text prompt conditioning
+
+        Compares predictions against ground truth targets and prepares visualization.
+        Stores results for epoch-level aggregation.
+
+        Args:
+            batch: Input batch from validation dataloader
+            batch_idx: Index of current batch
+        """
+        # [Validation image generation and comparison logic...]
+        # Key steps:
+        # 1. Preprocess conditioning images to PIL format
+        # 2. Set up conditioning inputs (normal maps, position maps, DINO features)
+        # 3. Run pipeline inference with fixed prompt ("high quality")
+        # 4. Decode latent outputs to image space
+        # 5. Arrange predictions and ground truths for visualization
+
+        cond_imgs_tensor, _, target_imgs, normal_imgs, position_imgs = self.prepare_batch_data(batch)
+        resolution = self.view_size
+        image_pils = []
+        for i in range(cond_imgs_tensor.shape[0]):
+            image_pils.append([])
+            for j in range(cond_imgs_tensor.shape[1]):
+                image_pils[-1].append(v2.functional.to_pil_image(cond_imgs_tensor[i, j, ...]))
+
+        outputs, gts = [], []
+        for idx in range(len(image_pils)):
+            cond_imgs = image_pils[idx]
+
+            cached_condition = dict(num_in_batch=self.num_view, N_pbrs=len(self.pbr_settings))
+            if normal_imgs is not None:
+                cached_condition["images_normal"] = normal_imgs[0][idx, ...].unsqueeze(0)
+            if position_imgs is not None:
+                cached_condition["images_position"] = position_imgs[0][idx, ...].unsqueeze(0)
+            if self.pipeline.unet.use_dino:
+                dino_hidden_states = self.dino_v2([cond_imgs][0])
+                cached_condition["dino_hidden_states"] = dino_hidden_states
+
+            latent = self.pipeline(
+                cond_imgs,
+                prompt="high quality",
+                num_inference_steps=30,
+                output_type="latent",
+                height=resolution,
+                width=resolution,
+                **cached_condition,
+            ).images
+
+            image = self.pipeline.vae.decode(latent / self.pipeline.vae.config.scaling_factor, return_dict=False)[
+                0
+            ]  # [-1, 1]
+            image = (image * 0.5 + 0.5).clamp(0, 1)
+
+            image = rearrange(
+                image, "(b n_pbr n) c h w -> b n_pbr n c h w", n_pbr=len(self.pbr_settings), n=self.num_view
+            )
+            image = torch.cat((torch.ones_like(image[:, :, :1, ...]) * 0.5, image), dim=2)
+            image = rearrange(image, "b n_pbr n c h w -> (b n_pbr n) c h w")
+            image = rearrange(
+                image,
+                "(b n_pbr n) c h w -> b c (n_pbr h) (n w)",
+                b=1,
+                n_pbr=len(self.pbr_settings),
+                n=self.num_view + 1,
+            )
+            outputs.append(image)
+
+        all_target_pbrs = []
+        for pbr_token in self.pbr_settings:
+            all_target_pbrs.append(target_imgs[pbr_token])
+        all_target_pbrs = torch.stack(all_target_pbrs, dim=0).transpose(1, 0)
+        all_target_pbrs = torch.cat(
+            (cond_imgs_tensor.unsqueeze(1).repeat(1, len(self.pbr_settings), 1, 1, 1, 1), all_target_pbrs), dim=2
+        )
+        all_target_pbrs = rearrange(all_target_pbrs, "b n_pbrs n c h w -> b c (n_pbrs h) (n w)")
+        gts = all_target_pbrs
+        outputs = torch.cat(outputs, dim=0).to(self.device)
+        images = torch.cat([gts, outputs], dim=-2)
+        self.validation_step_outputs.append(images)
+
+    @torch.no_grad()
+    def on_validation_epoch_end(self):
+        """Aggregates validation results at epoch end.
+
+        Gathers outputs from all GPUs (if distributed training),
+        creates a unified visualization grid, and saves to disk.
+        Only rank 0 process performs saving.
+        """
+        # [Result aggregation and visualization...]
+        # Key steps:
+        # 1. Gather validation outputs from all processes
+        # 2. Create image grid combining ground truths and predictions
+        # 3. Save visualization with step-numbered filename
+        # 4. Clear memory for next validation cycle
+
+        images = torch.cat(self.validation_step_outputs, dim=0)
+        all_images = self.all_gather(images)
+        all_images = rearrange(all_images, "r b c h w -> (r b) c h w")
+
+        if self.global_rank == 0:
+            grid = make_grid(all_images, nrow=8, normalize=True, value_range=(0, 1))
+            save_image(grid, os.path.join(self.logdir, "images_val", f"val_{self.global_step:07d}.png"))
+
+        self.validation_step_outputs.clear()  # free memory
+
+    def configure_optimizers(self):
+        lr = self.learning_rate
+        optimizer = torch.optim.AdamW(self.unet.parameters(), lr=lr)
+
+        def lr_lambda(step):
+            warm_up_step = 1000
+            T_step = 9000
+            gamma = 0.9
+            min_lr = 0.1 if step >= warm_up_step else 0.0
+            max_lr = 1.0
+            normalized_step = step % (warm_up_step + T_step)
+            current_max_lr = max_lr * gamma ** (step // (warm_up_step + T_step))
+            if current_max_lr < min_lr:
+                current_max_lr = min_lr
+            if normalized_step < warm_up_step:
+                lr_step = min_lr + (normalized_step / warm_up_step) * (current_max_lr - min_lr)
+            else:
+                step_wc_wp = normalized_step - warm_up_step
+                ratio = step_wc_wp / T_step
+                lr_step = min_lr + 0.5 * (current_max_lr - min_lr) * (1 + math.cos(math.pi * ratio))
+            return lr_step
+
+        lr_scheduler = torch.optim.lr_scheduler.LambdaLR(optimizer, lr_lambda)
+
+        lr_scheduler_config = {
+            "scheduler": lr_scheduler,
+            "interval": "step",
+            "frequency": 1,
+            "monitor": "val_loss",
+            "strict": False,
+            "name": None,
+        }
+
+        return {"optimizer": optimizer, "lr_scheduler": lr_scheduler_config}