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---

license: mit
tags:
- pytorch
- diffusers
- class-conditional-image-generation
- diffusion-models-class
---




# This model is a diffusion model for generate number.

## Usage

```python

# 定义模型

class ClassConditionalUnet(nn.Module):

    def __init__(self, num_classes=10, class_emb_size=4):

        super().__init__()

        # 将数字所属的类别映射到一个长度为class_emb_size的特征向量

        self.class_emb = nn.Embedding(num_classes, class_emb_size)

        # self.model就是一个不带条件的unet模型,在这里给他添加额外的输入通道,用于接收条件信息

        self.model = UNet2DModel(

            sample_size=28,  #生成的图像是28*28

            in_channels=1 + class_emb_size,  #加入额外的输入通道

            out_channels=1,  # 输入单通道黑白数字图

            layers_per_block=2,  # 设置一个unet模块有多少个残差连接层

            block_out_channels=(32, 64, 64),

            down_block_types=(

                "DownBlock2D",  #普通的ResNet下采样模块

                "AttnDownBlock2D",  #含有spatial self-attention的下采样和模块

                "AttnDownBlock2D",



            ),

            up_block_types=(

                "AttnUpBlock2D",  #含有spatial self-attention的ResNet上采样模块

                "AttnUpBlock2D",

                "UpBlock2D",

            ),

        )



    def forward(self, x, t, class_labels):

        bs, ch, w, h = x.shape

        class_cond = self.class_emb(class_labels)  # 将类别映射为向量形式

        class_cond = class_cond.view(bs, class_cond.shape[1], 1, 1).expand(bs, class_cond.shape[1], w,

                                                                                 h)  # 拓展张量形状

        net_input = torch.cat((class_cond, x), dim=1)

        return self.model(net_input, t).sample        

    ckpt = torch.load("class_cond_unet.pth", map_location="cpu")



    model = ClassConditionalUnet(

    num_classes=ckpt["num_classes"],

    class_emb_size=ckpt["class_emb_size"]

)



    model.load_state_dict(ckpt["model_state_dict"])

    model.eval()

    noise_scheduler = DDPMScheduler.from_pretrained("Dirry525/class_num_generator")

```