app.py

import gradio as gr
import numpy as np
from PIL import Image
import heapq

def dijkstra_pathfinding(obstacles, speeds, source, target):
    """Simple Dijkstra pathfinding to demonstrate the algorithm"""
    H, W = obstacles.shape
    sx, sy = source
    tx, ty = target
    
    # Distance map
    dist = np.full((H, W), np.inf)
    dist[sy, sx] = 0.0
    
    # Parent tracking for path reconstruction
    parent = {}
    
    # Priority queue: (distance, x, y)
    pq = [(0.0, sx, sy)]
    visited = set()
    
    # 4-connected neighbors
    neighbors = [(-1, 0), (1, 0), (0, -1), (0, 1)]
    
    while pq:
        d, x, y = heapq.heappop(pq)
        
        if (x, y) in visited:
            continue
        
        visited.add((x, y))
        
        if (x, y) == (tx, ty):
            break
        
        for dx, dy in neighbors:
            nx, ny = x + dx, y + dy
            
            if 0 <= nx < W and 0 <= ny < H:
                if obstacles[ny, nx] > 0.5:  # Blocked
                    continue
                
                # Cost = 1 / speed (slower = higher cost)
                step_speed = max(speeds[ny, nx], 0.1)
                cost = 1.0 / step_speed
                new_dist = d + cost
                
                if new_dist < dist[ny, nx]:
                    dist[ny, nx] = new_dist
                    parent[(nx, ny)] = (x, y)
                    heapq.heappush(pq, (new_dist, nx, ny))
    
    # Reconstruct path
    if (tx, ty) not in parent and (tx, ty) != (sx, sy):
        return []  # No path found
    
    path = []
    current = (tx, ty)
    
    while current != (sx, sy):
        path.append(current)
        if current not in parent:
            break
        current = parent[current]
    
    path.append((sx, sy))
    path.reverse()
    
    return path


def generate_pathfinding_demo(grid_size, obstacle_density, source_x, source_y, target_x, target_y):
    """Generate pathfinding visualization with actual path calculation"""
    
    # Generate obstacles
    np.random.seed(42)  # Fixed seed for consistency
    obstacles = np.random.random((grid_size, grid_size)) < (obstacle_density / 100)
    obstacles = obstacles.astype(np.float32)
    
    # Ensure endpoints are free
    obstacles[source_y, source_x] = 0.0
    obstacles[target_y, target_x] = 0.0
    
    # Create speed field (uniform for simplicity)
    speeds = np.ones((grid_size, grid_size), dtype=np.float32)
    speeds[obstacles > 0.5] = 0.0  # Blocked cells have zero speed
    
    # Calculate path using Dijkstra
    path = dijkstra_pathfinding(obstacles, speeds, (source_x, source_y), (target_x, target_y))
    
    # Create visualization
    vis = np.zeros((grid_size, grid_size, 3), dtype=np.uint8)
    
    # Base colors
    vis[obstacles > 0.5] = [40, 40, 40]      # Obstacles: dark gray
    vis[obstacles < 0.5] = [200, 200, 200]   # Free space: light gray
    
    # Draw path in bright green (before marking endpoints)
    if path:
        for px, py in path:
            if 0 <= px < grid_size and 0 <= py < grid_size:
                vis[py, px] = [0, 255, 0]  # Bright green path
    
    # Mark source in red (larger, overwrites path)
    vis[max(0, source_y-2):min(grid_size, source_y+3), 
        max(0, source_x-2):min(grid_size, source_x+3)] = [255, 0, 0]  # Red source
    
    # Mark target in blue (larger, overwrites path)
    vis[max(0, target_y-2):min(grid_size, target_y+3), 
        max(0, target_x-2):min(grid_size, target_x+3)] = [0, 100, 255]  # Blue target
    
    # Calculate statistics
    blocked = int(np.sum(obstacles > 0.5))
    free = grid_size * grid_size - blocked
    straight_dist = np.hypot(target_x - source_x, target_y - source_y)
    path_length = len(path)
    path_ratio = path_length / max(straight_dist, 1.0) if path else 0.0
    
    stats = f"""
### Results

- **Grid Size**: {grid_size}×{grid_size} ({grid_size*grid_size:,} cells)
- **Obstacles**: {blocked:,} ({100*blocked/(grid_size*grid_size):.1f}%)
- **Free Cells**: {free:,} ({100*free/(grid_size*grid_size):.1f}%)
- **Straight Distance**: {straight_dist:.1f} cells
- **Path Found**: {"✅ Yes" if path else "❌ No path exists"}
- **Path Length**: {path_length} cells
- **Path Ratio**: {path_ratio:.2f}x (efficiency)

### GPU Solver Performance

The full Optical Neuromorphic GPU solver achieves:
- **30-300× speedup** vs this CPU Dijkstra
- **Sub-1% accuracy** (0.64% mean error)
- **Near-optimal paths** (1.025× optimal length)
- **Real-time** (2-4ms per query on 512×512 grids)

**Colors**: 🔴 Red=Start, 🔵 Blue=Goal, 🟢 Green=Path, ⬛ Black=Obstacles

This demo uses basic CPU Dijkstra. The full GPU implementation is 30-300× faster!
    """
    
    img = Image.fromarray(vis)
    return img, stats

# Gradio interface
with gr.Blocks(title="Optical Neuromorphic Eikonal Solver Demo", theme=gr.themes.Soft()) as demo:
    gr.Markdown("""
    # 🚀 Optical Neuromorphic Eikonal Solver
    
    **GPU-accelerated pathfinding with 30-300× speedup!**
    
    This demo shows pathfinding with basic CPU Dijkstra for comparison. 
    The full GPU solver is 30-300× faster using neuromorphic computing principles.
    
    🔗 **Full implementation**: [GitHub](https://github.com/Agnuxo1/optical-neuromorphic-eikonal-solver)
    """)
    
    with gr.Row():
        with gr.Column():
            gr.Markdown("### ⚙️ Configuration")
            grid_size = gr.Slider(64, 512, step=64, value=256, label="Grid Size")
            obstacle_density = gr.Slider(0, 50, step=5, value=20, label="Obstacle Density (%)")
            
            gr.Markdown("### 📍 Source (Red)")
            with gr.Row():
                source_x = gr.Slider(0, 255, step=1, value=10, label="Source X")
                source_y = gr.Slider(0, 255, step=1, value=10, label="Source Y")
            
            gr.Markdown("### 🎯 Target (Blue)")
            with gr.Row():
                target_x = gr.Slider(0, 255, step=1, value=245, label="Target X")
                target_y = gr.Slider(0, 255, step=1, value=245, label="Target Y")
            
            solve_btn = gr.Button("🎯 Find Path", variant="primary", size="lg")
        
        with gr.Column():
            gr.Markdown("### 🗺️ Pathfinding Visualization")
            output_img = gr.Image(label="Grid with Optimal Path", height=400)
            stats_text = gr.Markdown("Click 'Find Path' to calculate optimal route")
    
    def update_sliders(size):
        return [gr.update(maximum=size-1)] * 4
    
    grid_size.change(fn=update_sliders, inputs=[grid_size], 
                     outputs=[source_x, source_y, target_x, target_y])
    
    solve_btn.click(
        fn=generate_pathfinding_demo,
        inputs=[grid_size, obstacle_density, source_x, source_y, target_x, target_y],
        outputs=[output_img, stats_text]
    )
    
    gr.Markdown("""
    ---
    
    ## 📚 Resources & Links
    
    - **Paper (HTML)**: [Full Academic Paper](https://github.com/Agnuxo1/optical-neuromorphic-eikonal-solver/blob/main/optical_neuromorphic_paper.html)
    - **Source Code**: [GitHub Repository](https://github.com/Agnuxo1/optical-neuromorphic-eikonal-solver)
    - **Datasets**: [HuggingFace](https://huggingface.co/datasets/Agnuxo/optical-neuromorphic-eikonal-benchmarks)
    - **OpenML**: [Datasets #47114-47118](https://www.openml.org/search?type=data&sort=date&status=active)
    - **W&B Metrics**: [Weights & Biases](https://wandb.ai/lareliquia-angulo-agnuxo/optical-neuromorphic-eikonal-solver)
    
    ## 🏆 Benchmark Results
    
    | Grid Size | GPU Time | CPU Time | Speedup | Accuracy | Path Quality |
    |-----------|----------|----------|---------|----------|--------------|
    | 128×128 | 2.3 ms | 73.9 ms | **32×** | 0.52% error | 1.004× optimal |
    | 256×256 | 3.1 ms | 275.5 ms | **89×** | 0.55% error | 1.015× optimal |
    | 512×512 | 4.1 ms | 948.9 ms | **231×** | 0.69% error | 1.042× optimal |
    | **Average** | **3.3 ms** | **505 ms** | **135×** | **0.64% error** | **1.025× optimal** |
    
    ## 🧠 How It Works
    
    The GPU solver uses **neuromorphic computing** principles:
    - Each grid cell maintains 4 directional memory states (N, E, S, W)
    - Information propagates like waves through the medium
    - All cells update in parallel on GPU (massively parallel)
    - System converges to optimal solution in ~2n iterations
    - No priority queues → Full parallelization
    
    ## 👤 Author
    
    **Francisco Angulo de Lafuente**
    
    - [GitHub](https://github.com/Agnuxo1)
    - [ResearchGate](https://www.researchgate.net/profile/Francisco-Angulo-Lafuente-3)
    - [Kaggle](https://www.kaggle.com/franciscoangulo)
    - [HuggingFace](https://huggingface.co/Agnuxo)
    - [Wikipedia](https://es.wikipedia.org/wiki/Francisco_Angulo_de_Lafuente)
    
    ## 📜 Citation
    
    If you use this work, please cite:
    
    ```bibtex
    @software{angulo2025optical,
      author = {Angulo de Lafuente, Francisco},
      title = {Optical Neuromorphic Eikonal Solver},
      year = {2025},
      url = {https://github.com/Agnuxo1/optical-neuromorphic-eikonal-solver}
    }
    ```
    """)

demo.launch()