plot_sample.py

#!/usr/bin/env python3
"""
Plot a single sample from the Chladni 2D dataset.

Visualizes the forcing function and displacement response patterns
for a single Chladni plate sample using imshow plots.
"""

import numpy as np
import matplotlib.pyplot as plt
from dataset import Chladni2DDataset


def plot_chladni_sample(sample, save_path="sample_plot.png"):
    """
    Plot a single sample from the Chladni 2D dataset.
    
    Creates side-by-side imshow plots of the forcing function and 
    displacement response patterns. The forcing function shows the
    spatial distribution of applied forces, while the displacement
    response shows the resulting vibration pattern of the plate.
    
    Args:
        sample (dict): Dictionary returned by Chladni2DDataset containing
                      forcing patterns, displacement responses, and metadata
        save_path (str): Path to save the plot image (default: "sample_plot.png")
    
    Example:
        >>> dataset = Chladni2DDataset()
        >>> sample = next(iter(dataset))
        >>> plot_chladni_sample(sample, "my_plot.png")
        Saved plot: my_plot.png
    """
    # Extract data
    forcing = sample["forcing"]  # 2D forcing function
    displacement = sample["displacement"]  # 2D displacement response
    frequency = sample["frequency"]

    # Create figure with subplots
    fig, axs = plt.subplots(1, 2, figsize=(15, 6), facecolor="white")

    # Plot 1: Forcing function S
    ax1 = axs[0]
    ax1.set_facecolor("white")
    im1 = ax1.imshow(
        forcing.T, 
        extent=[0, sample["plate_length_x"], 0, sample["plate_length_y"]],
        origin='lower',
        cmap="viridis",
        aspect='equal'
    )
    ax1.set_xlabel("X axis (m)", fontsize=14)
    ax1.set_ylabel("Y axis (m)", fontsize=14)
    ax1.set_title("Forcing Function S(x,y)", fontsize=16, fontweight="bold")
    ax1.tick_params(labelsize=12)
    ax1.grid(True, alpha=0.3)

    # Add colorbar with proper labels
    cbar1 = plt.colorbar(im1, ax=ax1)
    cbar1.set_label("Forcing Amplitude", rotation=270, labelpad=25, fontsize=14)
    cbar1.ax.tick_params(labelsize=12)

    # Plot 2: Displacement response Z
    ax2 = axs[1]
    ax2.set_facecolor("white")
    im2 = ax2.imshow(
        displacement.T,
        extent=[0, sample["plate_length_x"], 0, sample["plate_length_y"]],
        origin='lower',
        cmap="RdBu_r",
        aspect='equal'
    )
    ax2.set_xlabel("X axis (m)", fontsize=14)
    ax2.set_ylabel("Y axis (m)", fontsize=14)
    ax2.set_title(
        f"Displacement Response Z(x,y), f = {frequency:.2f} Hz",
        fontsize=16,
        fontweight="bold",
    )
    ax2.tick_params(labelsize=12)
    ax2.grid(True, alpha=0.3)

    # Add colorbar
    cbar2 = plt.colorbar(im2, ax=ax2)
    cbar2.set_label("Displacement Amplitude", rotation=270, labelpad=25, fontsize=14)
    cbar2.ax.tick_params(labelsize=12)

    plt.tight_layout()

    # Save the plot
    plt.savefig(save_path, facecolor="white", dpi=150, bbox_inches="tight")
    print(f"Saved plot: {save_path}")

    plt.show()
    plt.close(fig)


if __name__ == "__main__":
    """
    Generate and visualize a sample from the Chladni 2D dataset.
    
    This script creates a dataset instance, generates a single sample,
    prints information about the sample structure, and creates a
    visualization showing both the forcing pattern and displacement response.
    """
    # Set random seed for reproducibility
    np.random.seed(42)

    print("Chladni 2D Dataset Visualization")
    print("=" * 35)

    # Create dataset instance
    dataset = Chladni2DDataset(numPoints=50, n_range=10, m_range=10)
    
    print(f"Dataset configuration:")
    print(f"  Grid resolution: {dataset.numPoints}x{dataset.numPoints}")
    print(f"  Modal basis: {dataset.n_range}x{dataset.m_range}")
    print(f"  Plate dimensions: {dataset.L:.3f}x{dataset.M:.3f} m")
    print(f"  Driving frequency: {dataset.omega/(2*np.pi):.1f} Hz")

    # Generate a single sample
    dataset_iter = iter(dataset)
    sample = next(dataset_iter)
    sample = next(dataset_iter)

    print(f"\nSample structure:")
    print("-" * 20)
    for key, value in sample.items():
        if hasattr(value, 'shape'):
            print(f"  {key:20s}: {str(value.shape):15s}")
        else:
            print(f"  {key:20s}: {type(value).__name__} = {value}")

    # Plot the sample
    print(f"\nGenerating visualization...")
    plot_chladni_sample(sample)
    print("Visualization complete!")