costas.c
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#include <stdio.h>
#include <stdlib.h>
//#include <fcntl.h>
//#include <errno.h>
#include <ctype.h>
#include <string.h>
#include <paccs.h>
/*
Costas arrays (communicated by Daniel Diaz)
*/
#define diffs(a, b) diffs[(a) * (N - 1) + (b)]
int main(int argc, char *argv[])
{
int solutions = 0, one_solution = 1;
int use_label = 0;
int i, j;
int verbose = 0;
fd_int *array, *diffs;
int N = 10;
int coeffs[] = { 1, 1, -1 };
fd_int diffeq[3];
int k;
fd_init(&argc, &argv);
for (i = 1; i < argc; ++i)
if (!strcmp(argv[i], "--all"))
one_solution = 0;
else if (!strcmp(argv[i], "--label"))
use_label = 1;
else if (!strncmp(argv[i], "-v", 2))
{
char *s = argv[i] + 1;
while (*s++ == 'v')
verbose++;
}
else if (isdigit(*argv[i]))
{
N = atoi(argv[i]);
i++;
break;
}
else
fd__error("%s: unknown option `%s'\n", argv[0], argv[i]);
array = calloc(N, sizeof(*array));
for (j = 0; i < argc; ++j, ++i)
{
int a, b;
a = b = atoi(argv[i]);
if (strchr(argv[i], '-'))
b = atoi(strchr(argv[i], '-') + 1);
array[j] = fd_new(a - 1, b - 1);
}
for (; j < N; ++j)
array[j] = fd_new(0, N - 1);
fd_all_different(array, N);
if (use_label)
fd_label(array, N);
// differences:
// 0 <= array[] < N
// -> -(N-1) <= array[i] - array[j] <= N-1
// -> 0 <= array[i] - array[j] + N-1 <= 2*(N-1)
diffs = calloc((N - 2) * (N - 1), sizeof(*diffs));
for (i = 0; i < N - 2; ++i)
for (j = 0; j < N - 1 - i; ++j)
diffs(i, j) = fd_new(0, 2 * (N - 1));
diffeq[0] = fd_const(N - 1);
for (k = 1; k < N - 1; ++k)
{
for (i = k; i < N; ++i)
{
diffeq[1] = array[i];
diffeq[2] = array[i - k];
fd_poly_eq(coeffs, diffeq, 3, diffs(k - 1, i - k));
if (verbose >= 2)
printf("x[%d] - x[%d] -> (%d,%d)\n", i, i-k, k-1, i-k);
}
fd_all_different(&diffs(k - 1, 0), N - k);
}
while (fd_solve() == FD_OK)
{
printf("solution %d:\n", ++solutions);
for (i = 0; i < N; ++i)
{
printf("%d", fd_var_value(array[i]) + 1);
if (i != N - 1)
putchar(' ');
}
putchar('\n');
if (verbose >= 1)
for (k = 1; k < N - 1; ++k)
{
printf("%*s", k, "");
for (i = k; i < N; ++i)
printf("%d ", fd_var_value(diffs(k - 1, i - k)) - (N - 1));
putchar('\n');
}
#if !(defined(LOCAL_SEARCH) || defined(DISTRIBUTED_SOLVER))
if (one_solution)
#endif
break;
}
fd_end();
{
// avoid failure messages from mpirun
extern int _fd_counting_solutions; // XXX: private variable
if (_fd_counting_solutions)
return 0;
}
if (solutions)
printf("%d solutions found\n", solutions);
else
printf("inconsistent CSP\n");
return !solutions;
}