91 lines
2.3 KiB
C
91 lines
2.3 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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void mysub(int n, double *x, double *y)
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{
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return;
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}
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main()
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{
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/* Parameters */
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#define NMAX 1000
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#define ITS 100000
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int i, j, iters;
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double alpha, avg, t1, t2, tnotim;
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double x[NMAX], y[NMAX];
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double SuperLU_timer_();
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/* Initialize X and Y */
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for (i = 0; i < NMAX; ++i) {
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x[i] = 1.0 / (double)(i+1);
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y[i] = (double)(NMAX - i) / (double)NMAX;
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}
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alpha = 0.315;
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/* Time DAXPY operations */
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iters = ITS;
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tnotim = 0.0;
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while ( tnotim <= 0.0 ) {
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t1 = SuperLU_timer_();
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for (j = 0; j < iters; ++j) {
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for (i = 0; i < NMAX; ++i) y[i] += alpha * x[i];
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alpha = -alpha;
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}
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t2 = SuperLU_timer_();
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tnotim = t2 - t1;
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if ( tnotim > 0. ){
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float ops = 2.0 * iters * NMAX * 1e-9;
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printf("Time for %d DAXPYs = %10.3g seconds\n",
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iters, tnotim);
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printf("DAXPY performance rate = %10.3g Gflops\n", ops/tnotim);
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} else {
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/* this makes sure we dont keep trying forever */
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if ( iters > 100000000 ) {
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printf("*** Error: Time for operations was zero.\n"
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"\tThe timer may not be working correctly.\n");
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/*exit(9);*/
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}
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iters *= 10;
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}
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}
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/* Force gcc not to optimize away the previous loop (DCS) */
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printf("y[0]=%g\n", y[0]) ;
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t1 = SuperLU_timer_();
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for (j = 0; j < ITS; ++j) {
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for (i = 0; i < NMAX; ++i)
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y[i] += alpha * x[i];
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alpha = -alpha;
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}
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t2 = SuperLU_timer_();
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tnotim = t2 - t1;
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/* Time 1,000,000 DAXPY operations with SuperLU_timer_()
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in the outer loop */
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t1 = SuperLU_timer_();
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for (j = 0; j < ITS; ++j) {
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for (i = 0; i < NMAX; ++i)
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y[i] += alpha * x[i];
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alpha = -alpha;
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t2 = SuperLU_timer_();
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}
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/* Compute the time in milliseconds used by an average call to
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SuperLU_timer_(). */
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printf("Including DSECND, time = %10.3g seconds\n", t2-t1);
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avg = ( (t2 - t1) - tnotim )*1000. / (double)ITS;
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printf("Average time for DSECND = %10.3g milliseconds\n", avg);
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/* Compute the equivalent number of floating point operations used
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by an average call to DSECND. */
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if ( tnotim > 0. )
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printf("Equivalent floating point ops = %10.3g ops\n",
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1000.*avg / tnotim);
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mysub(NMAX, x, y);
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return 0;
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}
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