WriteText.c File Reference

Write a vector field and its grid to a text file. More...

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <basic.h>
#include <arrayfunctions.h>

Go to the source code of this file.

Functions
int	WriteText (int ndims, int nvars, int *dim, double *x, double *u, char *f, int *index)

Detailed Description

Write a vector field and its grid to a text file.

Author

Debojyoti Ghosh

Definition in file WriteText.c.

Function Documentation

int WriteText	(	int	ndims,
		int	nvars,
		int *	dim,
		double *	x,
		double *	u,
		char *	f,
		int *	index
	)

Write a vector field and its associated grid to a text file. The data is written to the text file in the following format:

Each line of the file contains
i0 i1 ... i{ndims-1} x0[i0] x1[i1] ... x{ndims-1}[i{ndims-1}] u0[p] u1[p] ... u{nvars-1}[p]

where
(i0,i1,...,i{ndims-1}) represents a ndims-dimensional grid index,
x0, x1, ..., x{ndims-1} are the spatial dimensions (e.g. in 3D, ndims = 3, x0 = x, x1 = y, x2 = z)
u0, u1, ..., u{nvars-1} are the components of the vector field u
p = i0 + dim[0] * (i1 + dim[1] * (i2 + dim[2] * ( ... + dim[ndims-2] * i{ndims-1} ))) (see _ArrayIndexnD_)
Thus, the number of lines is dim[0]*dim[1]*...*dim[ndims-1]

This is a plain text file, so it can be visualized using, say MATLAB, or any software that can read data from a plain text file. For 1D (ndims = 1), the data can be easily plotted in Gnuplot (for example).

Parameters

ndims	Number of spatial dimensions
nvars	Number of variables at each grid point
dim	Integer array with the number of grid points in each spatial dimension as its entries
x	Array of spatial coordinates representing a Cartesian grid (no ghost points)
u	Array containing the vector field to write (no ghost points)
f	Filename
index	Preallocated integer array of size ndims

Definition at line 27 of file WriteText.c.

{
  FILE *out;
  out = fopen(f,"w");
  if (!out) {
    fprintf(stderr,"Error: could not open %s for writing.\n",f);
    return(1);
  }

  int done = 0; _ArraySetValue_(index,ndims,0);
  while (!done) {
    int i, p;
    _ArrayIndex1D_(ndims,dim,index,0,p);
    for (i=0; i<ndims; i++) fprintf(out,"%4d ",index[i]);
    for (i=0; i<ndims; i++) {
      int j,offset = 0; for (j=0; j<i; j++) offset += dim[j];
      fprintf(out,"%+1.16E ",x[offset+index[i]]);
    }
    for (i=0; i<nvars; i++) fprintf(out,"%+1.16E ",u[nvars*p+i]);
    fprintf(out,"\n");
    _ArrayIncrementIndex_(ndims,dim,index,done);
  }
  fclose(out);
  return(0);
}