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/*
* Copyright (C) 1994-1995. James Darrell McCauley. (darrell@mccauley-usa.com)
* http://mccauley-usa.com/
*
* This program is free software under the GPL (>=v2)
* Read the file GPL.TXT coming with GRASS for details.
*/
#include <sys/types.h> /* for getpid() */
#include <unistd.h>
#include <stdlib.h>
#include <math.h>
#include "gis.h"
#include "Vect.h"
#include "quaddefs.h"
#ifndef RAND_MAX
#define RAND_MAX (pow(2.0,31.0)-1)
#endif
#define R_INIT srand
#define RANDOM(lo,hi) ((double) rand() / (double)RAND_MAX * (hi-lo) + lo)
/*
#define R_MAX 1.0
#define R_INIT srand48
#define RANDOM(lo,hi) (drand48()/R_MAX*(hi-lo)+lo)
*/
/*
* returns Z struct filled with centers of n non-overlapping circles of
* radius r contained completely within window
*/
COOR *find_quadrats (int n, double r, struct Cell_head window, int verbose)
{
int i = 1, j, overlapped;
unsigned k;
double east, north, e_max, e_min, n_max, n_min;
COOR *quads=NULL;
quads = (COOR *) G_malloc ( n * sizeof(COOR) );
if (quads == NULL)
G_fatal_error ("cannot allocate memory for quadrats");
srand ((unsigned int)getpid());
/* R_INIT (1); */
e_max = window.east - r;
e_min = window.west + r;
n_max = window.north - r;
n_min = window.south + r;
quads[0].x = RANDOM (e_min, e_max);
quads[0].y = RANDOM (n_min, n_max);
while (i < n)
{
k=0;
if (verbose)
G_percent (i, n, 1);
overlapped = 1;
while (overlapped)
{
east = RANDOM (e_min, e_max);
north = RANDOM (n_min, n_max);
k++;
overlapped = 0;
for (j = i; j >= 0; --j)
{
if (hypot (quads[j].x - east, quads[j].y - north) < 2 * r)
{
overlapped = 1;
j = -1;
}
}
if (k==n*n)
G_warning("Having difficulties fitting that many circles with that radius");
if (k==2*n*n)
G_fatal_error("Maximum number of iterations exceeded\nTry smaller radius or smaller number of quads");
}
if (verbose)
G_percent (i, n, 1);
quads[i].x = east;
quads[i].y = north;
i++;
}
return quads;
}
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