Code to post-process ISPG coupling output ASCII file.

Ayush Kumar

The script does the following (for each coupling ID):

1. Uses matplotlib to generate Reaction force plots (fx, fy, fz)
2. Generates a plot for the area covered by the ISPG part under the lagrangian part.

Ayush Kumar

import os

import pandas as pd

import matplotlib.pyplot as plt

import re

import argparse

import sys


# Create a parser object

parser = argparse.ArgumentParser(

    description="Parse ISPG coupling file and plot data.")


# Required filepath argument

parser.add_argument("filepath", type=str, help="ISPG coupling file path.")


# Optional --add argument for coupling IDs to sum

parser.add_argument("--add", nargs='+', type=int,

                    help="List of coupling IDs to sum and plot (only for forces).")


# Parse arguments

args = parser.parse_args()

file_path = args.filepath

coupling_ids_to_add = args.add if args.add else []


# Open the file and parse the content

data = []

current_time = None


with open(file_path, 'r') as file:

    for line in file:

        line = line.strip()

        time_match = re.match(r'time = +(.+E[+\-]\d{2})', line)

        if time_match:

            current_time = float(time_match.group(1).replace('E', 'e'))


        if current_time is not None and re.match(r'^\s*\d', line):

            parts = line.split()

            if len(parts) >= 5:

                row_data = [

                    current_time,

                    int(parts[0]),

                    float(parts[1]),

                    float(parts[2]),

                    float(parts[3]),

                    float(parts[4])

                ]

                data.append(row_data)


# Create a DataFrame

columns = ['time', 'ID', 'area', 'fx', 'fy', 'fz']

df = pd.DataFrame(data, columns=columns)


# Validate coupling IDs

if coupling_ids_to_add:

    existing_ids = set(df['ID'].unique())

    invalid_ids = [

        cid for cid in coupling_ids_to_add if cid not in existing_ids]

    if invalid_ids:

        print(

            f"Error: The following coupling IDs were not found in the data: {invalid_ids}")

        sys.exit(1)


# Plotting function



def plot_data(df, y_col, title, filename, coupling_ids_to_add):

    fig, ax = plt.subplots(figsize=(10, 6))


    # Plot each individual ID

    for ID in df['ID'].unique():

        id_data = df[df['ID'] == ID]

        ax.plot(id_data['time'], id_data[y_col], label=f'ID {ID}')


    # Plot summed line only for force columns

    if coupling_ids_to_add and y_col in ['fx', 'fy', 'fz']:

        summed_data = df[df['ID'].isin(coupling_ids_to_add)]

        summed_group = summed_data.groupby('time')[y_col].sum().reset_index()

        ax.plot(summed_group['time'], summed_group[y_col],

                label=f'Sum of IDs {coupling_ids_to_add}',

                linewidth=2, linestyle='--', color='black')


    file_path_image = os.path.join(os.path.dirname(file_path), filename)

    ax.set_title(title)

    ax.set_xlabel('Time')

    ax.set_ylabel(y_col)

    ax.grid(True)

    ax.legend()

    plt.show()

    fig.savefig(file_path_image)

    plt.close(fig)



# Create plots

plot_data(df, 'fx', 'fx vs Time', 'fx_vs_time.png', coupling_ids_to_add)

plot_data(df, 'fy', 'fy vs Time', 'fy_vs_time.png', coupling_ids_to_add)

plot_data(df, 'fz', 'fz vs Time', 'fz_vs_time.png', coupling_ids_to_add)

# No summed line for area

plot_data(df, 'area', 'Area vs Time', 'area_vs_time.png', [])