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update parallel flow

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zachary62 2025-03-25 14:24:18 -04:00
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1
README.md
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@ -73,6 +73,7 @@ From there, it's easy to implement popular design patterns like ([Multi-](https:
| [Multi-Agent](https://github.com/The-Pocket/PocketFlow/tree/main/cookbook/pocketflow-multi-agent) | ★☆☆ <br> *Beginner* | A Taboo word game for asynchronous communication between two agents |
| [Supervisor](https://github.com/The-Pocket/PocketFlow/tree/main/cookbook/pocketflow-supervisor) | ★☆☆ <br> *Beginner* | Research agent is getting unreliable... Let's build a supervision process|
| [Parallel](https://github.com/The-Pocket/PocketFlow/tree/main/cookbook/pocketflow-parallel-batch) | ★☆☆ <br> *Beginner* | A parallel execution demo that shows 3x speedup |
| [Parallel Flow](https://github.com/The-Pocket/PocketFlow/tree/main/cookbook/pocketflow-parallel-batch-flow) | ★☆☆ <br> *Beginner* | A parallel image processing demo showing 8x speedup with multiple filters |
| [Thinking](https://github.com/The-Pocket/PocketFlow/tree/main/cookbook/pocketflow-thinking) | ★☆☆ <br> *Beginner* | Solve complex reasoning problems through Chain-of-Thought |
| [Memory](https://github.com/The-Pocket/PocketFlow/tree/main/cookbook/pocketflow-chat-memory) | ★☆☆ <br> *Beginner* | A chat bot with short-term and long-term memory |

102
cookbook/pocketflow-parallel-batch-flow/README.md
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@ -1,75 +1,61 @@
# Parallel Image Processor (AsyncParallelBatchFlow Example)
# Parallel Image Processor
This example demonstrates how to use `AsyncParallelBatchFlow` to process multiple images with multiple filters in parallel.
Demonstrates how AsyncParallelBatchFlow processes multiple images with multiple filters >8x faster than sequential processing.
## How it Works
## Features
1. **Image Generation**: Creates sample images (gradient, checkerboard, circles)
2. **Filter Application**: Applies different filters (grayscale, blur, sepia) to each image
3. **Parallel Processing**: Processes all image-filter combinations concurrently
```mermaid
graph TD
subgraph AsyncParallelBatchFlow[Image Processing Flow]
subgraph AsyncFlow[Per Image-Filter Flow]
A[Load Image] --> B[Apply Filter]
B --> C[Save Image]
end
end
```
### Flow Structure
- Processes images with multiple filters in parallel
- Applies three different filters (grayscale, blur, sepia)
- Shows significant speed improvement over sequential processing
- Manages system resources with semaphores
```mermaid
graph TD
subgraph AsyncParallelBatchFlow[Image Processing Flow]
subgraph AsyncFlow[Per Image-Filter Flow]
A[Load Image] --> B[Apply Filter]
B --> C[Save Image]
end
end
```
## Run It
### Key Components
1. **LoadImage (AsyncNode)**
- Loads an image from file
- Uses PIL for image handling
2. **ApplyFilter (AsyncNode)**
- Applies the specified filter
- Supports grayscale, blur, and sepia
3. **SaveImage (AsyncNode)**
- Saves the processed image
- Creates output directory if needed
4. **ImageBatchFlow (AsyncParallelBatchFlow)**
- Manages parallel processing of all image-filter combinations
- Returns parameters for each sub-flow
## Running the Example
1. Install dependencies:
```bash
pip install -r requirements.txt
```
2. Run the example:
```bash
python main.py
```
## Sample Output
## Output
The example will:
1. Create 3 sample images: `cat.jpg`, `dog.jpg`, `bird.jpg`
2. Apply 3 filters to each image
3. Save results in `output/` directory (9 total images)
```=== Processing Images in Parallel ===
Parallel Image Processor
------------------------------
Found 3 images:
- images/bird.jpg
- images/cat.jpg
- images/dog.jpg
Example output structure:
```
output/
├── cat_grayscale.jpg
├── cat_blur.jpg
├── cat_sepia.jpg
├── dog_grayscale.jpg
Running sequential batch flow...
Processing 3 images with 3 filters...
Total combinations: 9
Loading image: images/bird.jpg
Applying grayscale filter...
Saved: output/bird_grayscale.jpg
...etc
Timing Results:
Sequential batch processing: 13.76 seconds
Parallel batch processing: 1.71 seconds
Speedup: 8.04x
Processing complete! Check the output/ directory for results.
```
## Key Concepts
## Key Points
1. **Parallel Flow Execution**: Each image-filter combination runs as a separate flow in parallel
2. **Parameter Management**: The batch flow generates parameters for each sub-flow
3. **Resource Management**: Uses semaphores to limit concurrent image processing
4. **Error Handling**: Gracefully handles failures in individual flows
- **Sequential**: Total time = sum of all item times
- Good for: Rate-limited APIs, maintaining order
- **Parallel**: Total time ≈ longest single item time
- Good for: I/O-bound tasks, independent operations

34
cookbook/pocketflow-parallel-batch-flow/flow.py
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@ -1,6 +1,6 @@
"""Flow definitions for parallel image processing."""
from pocketflow import AsyncFlow, AsyncParallelBatchFlow
from pocketflow import AsyncFlow, AsyncParallelBatchFlow, AsyncBatchFlow
from nodes import LoadImage, ApplyFilter, SaveImage, NoOp
def create_base_flow():
@ -17,9 +17,31 @@ def create_base_flow():
save - "default" >> noop
# Create flow
return AsyncFlow(start=load)
return load
class ImageBatchFlow(AsyncParallelBatchFlow):
class ImageBatchFlow(AsyncBatchFlow):
"""Flow that processes multiple images with multiple filters in batch."""
async def prep_async(self, shared):
"""Generate parameters for each image-filter combination."""
# Get list of images and filters
images = shared.get("images", [])
filters = ["grayscale", "blur", "sepia"]
# Create parameter combinations
params = []
for image_path in images:
for filter_type in filters:
params.append({
"image_path": image_path,
"filter": filter_type
})
print(f"Processing {len(images)} images with {len(filters)} filters...")
print(f"Total combinations: {len(params)}")
return params
class ImageParallelBatchFlow(AsyncParallelBatchFlow):
"""Flow that processes multiple images with multiple filters in parallel."""
async def prep_async(self, shared):
@ -37,14 +59,14 @@ class ImageBatchFlow(AsyncParallelBatchFlow):
"filter": filter_type
})
print(f"\nProcessing {len(images)} images with {len(filters)} filters...")
print(f"Processing {len(images)} images with {len(filters)} filters...")
print(f"Total combinations: {len(params)}")
return params
def create_flow():
def create_flows():
"""Create the complete parallel processing flow."""
# Create base flow for single image processing
base_flow = create_base_flow()
# Wrap in parallel batch flow
return ImageBatchFlow(start=base_flow)
return ImageBatchFlow(start=base_flow), ImageParallelBatchFlow(start=base_flow)

31
cookbook/pocketflow-parallel-batch-flow/main.py
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@ -1,8 +1,7 @@
import os
import asyncio
import numpy as np
from PIL import Image
from flow import create_flow
import time
from flow import create_flows
def get_image_paths():
"""Get paths of existing images in the images directory."""
@ -19,7 +18,7 @@ def get_image_paths():
if not image_paths:
raise ValueError(f"No images found in '{images_dir}' directory!")
print(f"\nFound {len(image_paths)} images:")
print(f"Found {len(image_paths)} images:")
for path in image_paths:
print(f"- {path}")
@ -27,7 +26,7 @@ def get_image_paths():
async def main():
"""Run the parallel image processing example."""
print("\nParallel Image Processor")
print("Parallel Image Processor")
print("-" * 30)
# Get existing image paths
@ -36,10 +35,26 @@ async def main():
# Create shared store with image paths
shared = {"images": image_paths}
# Create and run flow
flow = create_flow()
# Create both flows
batch_flow, parallel_batch_flow = create_flows()
await flow.run_async(shared)
# Run and time batch flow
start_time = time.time()
print("\nRunning sequential batch flow...")
await batch_flow.run_async(shared)
batch_time = time.time() - start_time
# Run and time parallel batch flow
start_time = time.time()
print("\nRunning parallel batch flow...")
await parallel_batch_flow.run_async(shared)
parallel_time = time.time() - start_time
# Print timing results
print("\nTiming Results:")
print(f"Sequential batch processing: {batch_time:.2f} seconds")
print(f"Parallel batch processing: {parallel_time:.2f} seconds")
print(f"Speedup: {batch_time/parallel_time:.2f}x")
print("\nProcessing complete! Check the output/ directory for results.")

25
cookbook/pocketflow-parallel-batch-flow/nodes.py
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@ -1,39 +1,22 @@
"""AsyncNode implementations for image processing."""
import os
import asyncio
from PIL import Image, ImageFilter
import numpy as np
from pocketflow import AsyncNode
class NoOp(AsyncNode):
"""Node that does nothing, used as a terminal node."""
async def prep_async(self, shared):
"""No preparation needed."""
return None
async def exec_async(self, prep_res):
"""No execution needed."""
return None
async def post_async(self, shared, prep_res, exec_res):
"""No post-processing needed."""
return None
class LoadImage(AsyncNode):
"""Node that loads an image from file."""
async def prep_async(self, shared):
"""Get image path from parameters."""
image_path = self.params["image_path"]
print(f"\nLoading image: {image_path}")
print(f"Loading image: {image_path}")
return image_path
async def exec_async(self, image_path):
"""Load image using PIL."""
# Simulate I/O delay
await asyncio.sleep(0.1)
await asyncio.sleep(0.5)
return Image.open(image_path)
async def post_async(self, shared, prep_res, exec_res):
@ -43,7 +26,6 @@ class LoadImage(AsyncNode):
class ApplyFilter(AsyncNode):
"""Node that applies a filter to an image."""
async def prep_async(self, shared):
"""Get image and filter type."""
image = shared["image"]
@ -83,7 +65,6 @@ class ApplyFilter(AsyncNode):
class SaveImage(AsyncNode):
"""Node that saves the processed image."""
async def prep_async(self, shared):
"""Prepare output path."""
image = shared["filtered_image"]
@ -101,7 +82,7 @@ class SaveImage(AsyncNode):
image, output_path = inputs
# Simulate I/O delay
await asyncio.sleep(0.1)
await asyncio.sleep(0.5)
image.save(output_path)
return output_path

4
docs/index.md
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@ -29,7 +29,7 @@ We model the LLM workflow as a **Graph + Shared Store**:
- [(Advanced) Parallel](./core_abstraction/parallel.md) nodes/flows handle I/O-bound tasks.
<div align="center">
<img src="https://github.com/the-pocket/.github/raw/main/assets/abstraction.png" width="900"/>
<img src="https://github.com/the-pocket/.github/raw/main/assets/abstraction.png" width="700"/>
</div>
## Design Pattern
@ -44,7 +44,7 @@ From there, it’s easy to implement popular design patterns:
- [(Advanced) Multi-Agents](./design_pattern/multi_agent.md) coordinate multiple agents.
<div align="center">
<img src="https://github.com/the-pocket/.github/raw/main/assets/design.png" width="900"/>
<img src="https://github.com/the-pocket/.github/raw/main/assets/design.png" width="700"/>
</div>
## Utility Function