postProcess/getData.c

Simulation Data Extraction

Extract and interpolate field data from Basilisk snapshots onto a regular grid.

• Author: Vatsal Sanjay ([email protected])
• Lab: CoMPhy Lab, Physics of Fluids Department
• Updated: March 8, 2025

Usage

./getData <filename> <xmin> <ymin> <xmax> <ymax> <ny>

Output: Grid data (x, y, field_values) to stderr

#include "utils.h"
#include "output.h"

VOF and velocity fields

scalar f[];
vector u[];

Command-line parameters

char filename[80];
int nx, ny, len;
double xmin, ymin, xmax, ymax, Deltax, Deltay;

Temperature field and scalar list

scalar T[];
scalar * list = NULL;

Main Function

Extract simulation data and interpolate onto a regular grid.

Parameters

• filename: Simulation snapshot file
• xmin, ymin: Lower bounds of extraction region
• xmax, ymax: Upper bounds of extraction region
  
• ny: Number of grid points in y-direction

Process

1. Parse arguments and validate input
2. Load simulation and normalize T field
3. Create uniform grid with spacing Deltay
4. Interpolate fields onto grid points
5. Output grid data to stderr

int main(int a, char const *arguments[]) {
  if (a != 7) {
    fprintf(stderr, "Error: Expected 6 arguments\n");
    fprintf(stderr, "Usage: %s <filename> <xmin> <ymin> <xmax> <ymax> <ny>\n",
            arguments[0]);
    return 1;
  }

  sprintf(filename, "%s", arguments[1]);
  xmin = atof(arguments[2]); ymin = atof(arguments[3]);
  xmax = atof(arguments[4]); ymax = atof(arguments[5]);
  ny = atoi(arguments[6]);

  list = list_add(list, T);

  /* Load simulation */
  restore(file = filename);

  /* Normalize T by maximum value */