WriteBinary.c File Reference

Write a vector field and its grid to a binary 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	WriteBinary (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 binary file.

Author

Debojyoti Ghosh

Definition in file WriteBinary.c.

Function Documentation

WriteBinary()

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

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

{
ndims
nvars
dim[0] dim[1] dim[2] ... dim[ndims-1]
x0_i (0 <= i < dim[0])
x1_i (0 <= i < dim[1])
...
x{ndims-1}_i (0 <= i < dim[ndims-1])
[u0,u1,...,u{nvars-1}]_p (0 <= p < N) (with no commas)
}

where
x0, x1, ..., x{ndims-1} represent the spatial dimensions (for a 3D problem, x0 = x, x1 = y, x2 = z),
u0, u1, ..., u{nvars-1} are each component of the vector u at a grid point,
N = dim[0]*dim[1]*...*dim[ndims-1] is the total number of points,
and p = i0 + dim[0]*( i1 + dim[1]*( i2 + dim[2]*( ... + dim[ndims-2] * i{ndims-1} ))) (see _ArrayIndexnD_)
with i0, i1, i2, etc representing grid indices along each spatial dimension, i.e.,
0 <= i0 < dim[0]-1
0 <= i1 < dim[1]-1
...
0 <= i{ndims-1} < dim[ndims=1]-1

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 34 of file WriteBinary.c.

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

  /* write ndims, nvars */
  bytes = fwrite(&ndims,sizeof(int),1,out);
  if ((int)bytes != 1) {
    fprintf(stderr,"Error in WriteBinary(): Unable to write ndims to output file.\n");
  }
  bytes = fwrite(&nvars,sizeof(int),1,out);
  if ((int)bytes != 1) {
    fprintf(stderr,"Error in WriteBinary(): Unable to write nvars to output file.\n");
  }

  /* write dimensions */
  bytes = fwrite(dim,sizeof(int),ndims,out);
  if ((int)bytes != ndims) {
    fprintf(stderr,"Error in WriteBinary(): Unable to write dimensions to output file.\n");
  }

  /* write grid */
  size = 0;
  for (d = 0; d < ndims; d++) size += dim[d];
  bytes = fwrite(x,sizeof(double),size,out);
  if ((int)bytes != size) {
    fprintf(stderr,"Error in WriteBinary(): Unable to write grid to output file.\n");
  }

  /* write solution */
  size = 1;
  for (d = 0; d < ndims; d++) size *= dim[d]; size *= nvars;
  bytes = fwrite(u,sizeof(double),size,out);
  if ((int)bytes != size) {
    fprintf(stderr,"Error in WriteBinary(): Unable to write solution to output file.\n");
  }

  fclose(out);
  return(0);
}