/* sinxypuv.c     sinxypuv  sin(x+y)    */
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "nuderiv.h"
#include "simeq.h"

static double p[25][25];
static double u[25][25];
static double v[25][25];
static double xg[25];
static double yg[25];
static int nx, ny;

int main(int argc, char * argv[])
{
  int i, j, n;
  FILE * outp;
  double pi, x, y, dx, dy, r;

  printf("sinxypuv.c running \n");
  if(argc<2)
  {
    printf("no file to write\n");
    exit(1);
  }
  else
  {
    printf("output file %s \n",argv[1]);
    outp = fopen(argv[1],"w");
    if(outp == NULL)
    {
      printf("can not open %s for writing. \n", argv[1]);
      exit(1);
    }
  }
  pi = 3.14159265358979323846;
  nx = 25;
  ny = 25;
  x = -1.0;
  y = -1.0;
  dx = 2.0/(double)(nx-1);
  dy = 2.0/(double)(ny-1);
  fprintf(outp, "%d %d \n", nx, ny);
  for(i=0; i<nx; i++)
  {
    xg[i] = x;
    for(j=0; j<ny; j++)
    {
      yg[j] = y;
      r = sqrt(x*x+y*y);
      p[i][j] = sin(2.0*pi*r+pi/2.0); /* cos(2*Pi*r) */
      u[i][j] = 2.0*sin(2.0*pi*r)*pi*x/r;
      v[i][j] = 2.0*sin(2.0*pi*r)*pi*y/r;
      fprintf(outp,"%f %f %f %f %f \n", xg[i], yg[j],
                                        p[i][j], u[i][j], v[i][j]);
      y = y + dy;
    }
    y = -1.0;
    x = x + dx;
  }
  fflush(outp);
  fclose(outp);

  printf("sinxypuv done. new %s file written \n", argv[1]);
  return 0;
} /* end sinxypuv.c */