【Hackathon 8th No.23】RFC：Improved Training of Wasserstein GANs 论文复现 (#1114)

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Author: XvLingWYY

rfcs/Science/20250404_add_wgan_gp_for_paddlescience.md

@@ -1,11 +1,11 @@
 # 在 PaddleScience 中复现 WGAN-GP 模型
 
-| 任务名称 | 在 PaddleScience 中复现 WGAN-GP 模型 |
-| --- | --- |
-| 提交作者 | robinbg |
-| 提交时间 | 2025-04-04 |
-| 版本号 | V1.0 |
-| 依赖飞桨版本 | develop |
+| 任务名称 | 在 PaddleScience 中复现 WGAN-GP 模型            |
+| --- |-------------------------------------------|
+| 提交作者 | robinbg、XvLingWYY                         |
+| 提交时间 | 2025-04-04                                |
+| 版本号 | V1.0                                      |
+| 依赖飞桨版本 | develop                                   |
 | 文件名 | 20250404_add_wgan_gp_for_paddlescience.md |
 
 # 一、概述
@@ -75,44 +75,106 @@ WGAN-GP 的核心在于其损失函数和梯度惩罚项的计算。以下是主
 
 ### 1.1 损失函数
 ```python
-# 生成器损失
-def generator_loss(fake_output):
-    return -paddle.mean(fake_output)
-
-# 判别器损失（包含梯度惩罚）
-def discriminator_loss(real_output, fake_output, gradient_penalty):
-    return paddle.mean(fake_output) - paddle.mean(real_output) + LAMBDA * gradient_penalty
+# CIFAR10实验中生成器损失
+class Cifar10GenFuncs:
+    """
+    Loss function for cifar10 generator
+    Args
+        discriminator_model: discriminator model
+        acgan_scale_g: scale of acgan loss for generator
+
+    """
+
+    def __init__(
+        self,
+        discriminator_model,
+        acgan_scale_g=0.1,
+    ):
+        self.crossEntropyLoss = paddle.nn.CrossEntropyLoss()
+        self.acgan_scale_g = acgan_scale_g
+        self.discriminator_model = discriminator_model
+
+    def loss(self, output_dict: Dict, *args):
+        fake_image = output_dict["fake_data"]
+        labels = output_dict["labels"]
+        outputs = self.discriminator_model({"data": fake_image, "labels": labels})
+        disc_fake, disc_fake_acgan = outputs["disc_fake"], outputs["disc_acgan"]
+        gen_cost = -paddle.mean(disc_fake)
+        if disc_fake_acgan is not None:
+            gen_acgan_cost = self.crossEntropyLoss(disc_fake_acgan, labels)
+            gen_cost += self.acgan_scale_g * gen_acgan_cost
+        return {"loss_g": gen_cost}
+
+# CIFAR10实验中判别器损失
+class Cifar10DisFuncs:
+    """
+    Loss function for cifar10 discriminator
+    Args
+        discriminator_model: discriminator model
+        acgan_scale: scale of acgan loss for discriminator
+
+    """
+
+    def __init__(self, discriminator_model, acgan_scale):
+        self.crossEntropyLoss = paddle.nn.CrossEntropyLoss()
+        self.acgan_scale = acgan_scale
+        self.discriminator_model = discriminator_model
+
+    def loss(self, output_dict: Dict, label_dict: Dict, *args):
+        fake_image = output_dict["fake_data"]
+        real_image = label_dict["real_data"]
+        labels = output_dict["labels"]
+        disc_fake = self.discriminator_model({"data": fake_image, "labels": labels})[
+            "disc_fake"
+        ]
+        out = self.discriminator_model({"data": real_image, "labels": labels})
+        disc_real, disc_real_acgan = out["disc_fake"], out["disc_acgan"]
+        gradient_penalty = self.compute_gradient_penalty(real_image, fake_image, labels)
+        disc_cost = paddle.mean(disc_fake) - paddle.mean(disc_real)
+        disc_wgan = disc_cost + gradient_penalty
+        if disc_real_acgan is not None:
+            disc_acgan_cost = self.crossEntropyLoss(disc_real_acgan, labels)
+            disc_acgan = disc_acgan_cost.sum()
+            disc_cost = disc_wgan + (self.acgan_scale * disc_acgan)
+        else:
+            disc_cost = disc_wgan
+        return {"loss_d": disc_cost}
+
+    def compute_gradient_penalty(self, real_data, fake_data, labels):
+        differences = fake_data - real_data
+        alpha = paddle.rand([fake_data.shape[0], 1])
+        interpolates = real_data + (alpha * differences)
+        gradients = paddle.grad(
+            outputs=self.discriminator_model({"data": interpolates, "labels": labels})[
+                "disc_fake"
+            ],
+            inputs=interpolates,
+            create_graph=True,
+            retain_graph=False,
+        )[0]
+        slopes = paddle.sqrt(paddle.sum(paddle.square(gradients), axis=1))
+        gradient_penalty = 10 * paddle.mean((slopes - 1.0) ** 2)
+        return gradient_penalty
 ```
 
 ### 1.2 梯度惩罚计算
 ```python
-def gradient_penalty(discriminator, real_samples, fake_samples):
-    # 生成随机插值系数
-    alpha = paddle.rand(shape=[real_samples.shape[0], 1, 1, 1])
-    
-    # 创建真实样本和生成样本之间的插值
-    interpolates = real_samples + alpha * (fake_samples - real_samples)
-    interpolates.stop_gradient = False
-    
-    # 计算判别器对插值样本的输出
-    disc_interpolates = discriminator(interpolates)
-    
-    # 计算梯度
-    gradients = paddle.grad(
-        outputs=disc_interpolates,
-        inputs=interpolates,
-        grad_outputs=paddle.ones_like(disc_interpolates),
-        create_graph=True,
-        retain_graph=True
-    )[0]
-    
-    # 计算梯度范数
-    gradients_norm = paddle.sqrt(paddle.sum(paddle.square(gradients), axis=[1, 2, 3]))
-    
-    # 计算梯度惩罚
-    gradient_penalty = paddle.mean(paddle.square(gradients_norm - 1.0))
-    
-    return gradient_penalty
+# CIFAR-10 判别器中的梯度惩罚计算
+def compute_gradient_penalty(self, real_data, fake_data, labels):
+  differences = fake_data - real_data
+  alpha = paddle.rand([fake_data.shape[0], 1])
+  interpolates = real_data + (alpha * differences)
+  gradients = paddle.grad(
+      outputs=self.discriminator_model({"data": interpolates, "labels": labels})[
+          "disc_fake"
+      ],
+      inputs=interpolates,
+      create_graph=True,
+      retain_graph=False,
+  )[0]
+  slopes = paddle.sqrt(paddle.sum(paddle.square(gradients), axis=1))
+  gradient_penalty = 10 * paddle.mean((slopes - 1.0) ** 2)
+  return gradient_penalty
 ```
 
 ## 2. 网络架构
@@ -135,34 +197,12 @@ WGAN-GP 的训练流程与标准 GAN 有所不同，主要区别在于：
 
 ```python
 # 训练循环示例
-for iteration in range(ITERATIONS):
-    # 训练判别器
-    for _ in range(CRITIC_ITERS):
-        real_data = next(data_iterator)
-        noise = paddle.randn([BATCH_SIZE, NOISE_DIM])
-        
-        # 计算判别器损失
-        fake_data = generator(noise)
-        real_output = discriminator(real_data)
-        fake_output = discriminator(fake_data)
-        gp = gradient_penalty(discriminator, real_data, fake_data)
-        d_loss = discriminator_loss(real_output, fake_output, gp)
-        
-        # 更新判别器参数
-        d_optimizer.clear_grad()
-        d_loss.backward()
-        d_optimizer.step()
-    
-    # 训练生成器
-    noise = paddle.randn([BATCH_SIZE, NOISE_DIM])
-    fake_data = generator(noise)
-    fake_output = discriminator(fake_data)
-    g_loss = generator_loss(fake_output)
-    
-    # 更新生成器参数
-    g_optimizer.clear_grad()
-    g_loss.backward()
-    g_optimizer.step()
+ for i in range(cfg.TRAIN.epochs):
+     logger.message(f"\nEpoch: {i + 1}\n")
+     optimizer_discriminator.clear_grad()
+     solver_discriminator.train()
+     optimizer_generator.clear_grad()
+     solver_generator.train()
 ```
 
 ## 4. 评估指标
@@ -171,11 +211,8 @@ for iteration in range(ITERATIONS):
 ### 4.1 Inception Score (IS)
 用于评估生成图像的质量和多样性。
 
-### 4.2 Fréchet Inception Distance (FID)
-测量生成图像分布与真实图像分布之间的距离。
-
-### 4.3 生成样本可视化
-定期保存生成的样本，用于直观评估模型性能。
+### 4.2 生成样本可视化
+保存生成的样本，用于直观评估模型性能。
 
 ## 5. 与 PaddleScience 集成
 我们将设计一个模块化的实现，便于与 PaddleScience 集成：
@@ -184,50 +221,142 @@ for iteration in range(ITERATIONS):
 ```
 PaddleScience/
 └── examples/
-    └── wgan_gp/
-        ├── __init__.py
-        ├── utils/
-        │   ├── __init__.py
-        │   ├── losses.py    # 损失函数
-        │   ├── metrics.py        # 评估指标
-        │   └── visualization.py     # 可视化工具
-        ├── models/
-        │   ├── __init__.py
-        │   ├── base_gan.py    # GAN 基类
-        │   ├── wgan.py        # WGAN 实现
-        │   └── wgan_gp.py     # WGAN-GP 实现
-        └── cases/
-            ├── wgan_gp_toy.py     # 玩具数据集示例
-            ├── wgan_gp_mnist.py   # MNIST 示例
-            └── wgan_gp_cifar.py   # CIFAR-10 示例
+    └── wgangp/
+        ├── conf
+        │  ├── wgangp_cifar10.yaml # CIFAR-10 配置文件
+        │  ├── wgangp_mnist.yaml # MNIST 配置文件
+        │  └── wgangp_toy.yaml # 玩具数据集配置文件
+        ├── function.py # 损失函数、评估指标、可视化工具
+        ├── wgangp_cifr10.py # CIFAR-10 示例 
+        ├── wgangp_cifar10_model.py # CIFAR-10实验模型
+        ├── wgangp_mnist.py # MNIST 示例
+        ├── wgangp_mnist_model.py # MNIST实验模型
+        └── wgangp_toy.py # 玩具数据集示例
+        └── wgangp_toy_model.py # 玩具数据集实验模型
 ```
 
 ### 5.2 接口设计
 提供简洁统一的接口，方便用户使用：
 
 ```python
 # 示例用法
-from models.wgan_gp import WGAN_GP
-
-# 创建模型
-model = WGAN_GP(
-    generator=generator_network,
-    discriminator=discriminator_network,
-    lambda_gp=10.0,
-    critic_iters=5
-)
-
-# 训练模型
-model.train(
-    train_data=dataset,
-    batch_size=64,
-    iterations=100000,
-    g_learning_rate=1e-4,
-    d_learning_rate=1e-4
-)
-
-# 生成样本
-samples = model.generate(num_samples=100)
+import os
+import paddle
+from functions import Cifar10DisFuncs
+from functions import Cifar10GenFuncs
+from functions import load_cifar10
+from omegaconf import DictConfig
+from wgangp_cifar10_model import WganGpCifar10Discriminator
+from wgangp_cifar10_model import WganGpCifar10Generator
+
+def train(cfg: DictConfig):
+    # set model
+    generator_model = WganGpCifar10Generator(**cfg["MODEL"]["gen_net"])
+    discriminator_model = WganGpCifar10Discriminator(**cfg["MODEL"]["dis_net"])
+    if cfg.TRAIN.pretrained_dis_model_path and os.path.exists(
+        cfg.TRAIN.pretrained_dis_model_path
+    ):
+        discriminator_model.load_dict(paddle.load(cfg.TRAIN.pretrained_dis_model_path))
+
+    # set Loss
+    generator_funcs = Cifar10GenFuncs(
+        **cfg["LOSS"]["gen"], discriminator_model=discriminator_model
+    )
+    discriminator_funcs = Cifar10DisFuncs(
+        **cfg["LOSS"]["dis"], discriminator_model=discriminator_model
+    )
+
+    # set dataloader
+    inputs, labels = load_cifar10(**cfg["DATA"])
+    dataloader_cfg = {
+        "dataset": {
+            "name": cfg["EVAL"]["dataset"]["name"],
+            "input": inputs,
+            "label": labels,
+        },
+        "sampler": {
+            **cfg["TRAIN"]["sampler"],
+        },
+        "batch_size": cfg["TRAIN"]["batch_size"],
+        "use_shared_memory": cfg["TRAIN"]["use_shared_memory"],
+        "num_workers": cfg["TRAIN"]["num_workers"],
+        "drop_last": cfg["TRAIN"]["drop_last"],
+    }
+
+    # set constraint
+    constraint_generator = ppsci.constraint.SupervisedConstraint(
+        dataloader_cfg=dataloader_cfg,
+        loss=ppsci.loss.FunctionalLoss(generator_funcs.loss),
+        output_expr={"labels": lambda out: out["labels"]},
+        name="constraint_generator",
+    )
+    constraint_generator_dict = {constraint_generator.name: constraint_generator}
+
+    constraint_discriminator = ppsci.constraint.SupervisedConstraint(
+        dataloader_cfg=dataloader_cfg,
+        loss=ppsci.loss.FunctionalLoss(discriminator_funcs.loss),
+        output_expr={"labels": lambda out: out["labels"]},
+        name="constraint_discriminator",
+    )
+    constraint_discriminator_dict = {
+        constraint_discriminator.name: constraint_discriminator
+    }
+
+    # set optimizer
+    lr_scheduler_generator = Linear(**cfg["TRAIN"]["lr_scheduler_gen"])()
+    lr_scheduler_discriminator = Linear(**cfg["TRAIN"]["lr_scheduler_dis"])()
+
+    optimizer_generator = ppsci.optimizer.Adam(
+        learning_rate=lr_scheduler_generator,
+        beta1=cfg["TRAIN"]["optimizer"]["beta1"],
+        beta2=cfg["TRAIN"]["optimizer"]["beta2"],
+    )
+    optimizer_discriminator = ppsci.optimizer.Adam(
+        learning_rate=lr_scheduler_discriminator,
+        beta1=cfg["TRAIN"]["optimizer"]["beta1"],
+        beta2=cfg["TRAIN"]["optimizer"]["beta2"],
+    )
+    optimizer_generator = optimizer_generator(generator_model)
+    optimizer_discriminator = optimizer_discriminator(discriminator_model)
+
+    # initialize solver
+    solver_generator = ppsci.solver.Solver(
+        model=generator_model,
+        output_dir=os.path.join(cfg.output_dir, "generator"),
+        constraint=constraint_generator_dict,
+        optimizer=optimizer_generator,
+        epochs=cfg.TRAIN.epochs_gen,
+        iters_per_epoch=cfg.TRAIN.iters_per_epoch_gen,
+        pretrained_model_path=cfg.TRAIN.pretrained_gen_model_path,
+    )
+    solver_discriminator = ppsci.solver.Solver(
+        model=generator_model,
+        output_dir=os.path.join(cfg.output_dir, "discriminator"),
+        constraint=constraint_discriminator_dict,
+        optimizer=optimizer_discriminator,
+        epochs=cfg.TRAIN.epochs_dis,
+        iters_per_epoch=cfg.TRAIN.iters_per_epoch_dis,
+        pretrained_model_path=cfg.TRAIN.pretrained_gen_model_path,
+    )
+
+    # train
+    for i in range(cfg.TRAIN.epochs):
+        logger.message(f"\nEpoch: {i + 1}\n")
+        optimizer_discriminator.clear_grad()
+        solver_discriminator.train()
+        optimizer_generator.clear_grad()
+        solver_generator.train()
+
+    # save model weight
+    paddle.save(
+        generator_model.state_dict(),
+        os.path.join(cfg.output_dir, "model_generator.pdparams"),
+    )
+    paddle.save(
+        discriminator_model.state_dict(),
+        os.path.join(cfg.output_dir, "model_discriminator.pdparams"),
+    )
+
 ```
 
 # 六、测试验收的考量