顺序管道块
[~modular_pipelines.SequentialPipelineBlocks] 是一种多块类型，它将其他 [~modular_pipelines.ModularPipelineBlocks] 按顺序组合在一起。数据通过 intermediate_inputs 和 intermediate_outputs 线性地从一个块流向下一个块。[~modular_pipelines.SequentialPipelineBlocks] 中的每个块通常代表管道中的一个步骤，通过组合它们，您逐步构建一个管道。
本指南向您展示如何将两个块连接成一个 [~modular_pipelines.SequentialPipelineBlocks]。
创建两个 [~modular_pipelines.ModularPipelineBlocks]。第一个块 InputBlock 输出一个 batch_size 值，第二个块 ImageEncoderBlock 使用 batch_size 作为 intermediate_inputs。
```py
from diffusers.modular_pipelines import ModularPipelineBlocks, InputParam, OutputParam
class InputBlock(ModularPipelineBlocks):
@property
def inputs(self):
return [
InputParam(name="prompt", type_hint=list, description="list of text prompts"),
InputParam(name="num_images_per_prompt", type_hint=int, description="number of images per prompt"),
]
@property
def intermediate_outputs(self):
return [
OutputParam(name="batch_size", description="calculated batch size"),
]
@property
def description(self):
return "A block that determines batch_size based on the number of prompts and num_images_per_prompt argument."
def __call__(self, components, state):
block_state = self.get_block_state(state)
batch_size = len(block_state.prompt)
block_state.batch_size = batch_size * block_state.num_images_per_prompt
self.set_block_state(state, block_state)
return components, state
```
```py
import torch
from diffusers.modular_pipelines import ModularPipelineBlocks, InputParam, OutputParam
class ImageEncoderBlock(ModularPipelineBlocks):
@property
def inputs(self):
return [
InputParam(name="image", type_hint="PIL.Image", description="raw input image to process"),
InputParam(name="batch_size", type_hint=int),
]
@property
def intermediate_outputs(self):
return [
OutputParam(name="image_latents", description="latents representing the image"
]
@property
def description(self):
return "Encode raw image into its latent presentation"
def __call__(self, components, state):
block_state = self.get_block_state(state)
# 模拟处理图像
# 这将改变所有块的图像状态，从PIL图像变为张量
block_state.image = torch.randn(1, 3, 512, 512)
block_state.batch_size = block_state.batch_size * 2
block_state.image_latents = torch.randn(1, 4, 64, 64)
self.set_block_state(state, block_state)
return components, state
```
通过定义一个[InsertableDict]来连接两个块，将块名称映射到块实例。块按照它们在blocks_dict中注册的顺序执行。
使用[~modular_pipelines.SequentialPipelineBlocks.from_blocks_dict]来创建一个[~modular_pipelines.SequentialPipelineBlocks]。
from diffusers.modular_pipelines import SequentialPipelineBlocks, InsertableDict
blocks_dict = InsertableDict()
blocks_dict["input"] = input_block
blocks_dict["image_encoder"] = image_encoder_block
blocks = SequentialPipelineBlocks.from_blocks_dict(blocks_dict)
通过调用blocks来检查[~modular_pipelines.SequentialPipelineBlocks]中的子块，要获取更多关于输入和输出的详细信息，可以访问docs属性。
print(blocks)
print(blocks.doc)