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[/] [openrisc/] [tags/] [gnu-src/] [gcc-4.5.1/] [gcc-4.5.1-or32-1.0rc2/] [libgomp/] [testsuite/] [libgomp.c/] [nqueens-1.c] - Rev 384
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/* { dg-do run } */ /* { dg-options "-O2 -fopenmp" } */ /* { dg-require-effective-target tls_runtime } */ #include <omp.h> #include <stdio.h> #include <string.h> int cnt; #pragma omp threadprivate (cnt) void nqueens (char *a, int n, int pos) { /* b[i] = j means the queen in i-th row is in column j. */ char b[pos + 1]; int i, j; memcpy (b, a, pos); for (i = 0; i < n; i++) { for (j = 0; j < pos; j++) if (b[j] == i || b[j] == i + pos - j || i == b[j] + pos - j) break; if (j < pos) continue; if (pos == n - 1) /* Found a solution. Could output it here. */ ++cnt; else { b[pos] = i; #pragma omp task nqueens (b, n, pos + 1); } } } int main (int argc, char **argv) { int n = 8; if (argc >= 2) n = strtoul (argv[1], NULL, 0); if (n < 1 || n > 127) { fprintf (stderr, "invalid count %d\n", n); return 1; } cnt = 0; double stime = omp_get_wtime (); nqueens ("", n, 0); printf ("serial N %d solutions # %d time %f\n", n, cnt, omp_get_wtime () - stime); #pragma omp parallel cnt = 0; stime = omp_get_wtime (); int tempcnt = 0; #pragma omp parallel reduction (+:tempcnt) { #pragma omp single nqueens ("", n, 0); tempcnt = cnt; } cnt = tempcnt; printf ("parallel N %d solutions # %d time %f\n", n, cnt, omp_get_wtime () - stime); return 0; }