source: CIVL/examples/openacc/acc_c2a/acc_c2a.c

/* 
 *     Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
 *
 * NVIDIA CORPORATION and its licensors retain all intellectual property
 * and proprietary rights in and to this software, related documentation
 * and any modifications thereto.  Any use, reproduction, disclosure or
 * distribution of this software and related documentation without an express
 * license agreement from NVIDIA CORPORATION is strictly prohibited.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <math.h>
#include <openacc.h>
#include <accelmath.h>

#if defined(_WIN32) || defined(_WIN64)
#include <sys/timeb.h>
#define gettime(a) _ftime(a)
#define usec(t1,t2) ((((t2).time-(t1).time)*1000+((t2).millitm-(t1).millitm))*100)
typedef struct _timeb timestruct;
#else
#include <sys/time.h>
#define gettime(a) gettimeofday(a,NULL)
#define usec(t1,t2) (((t2).tv_sec-(t1).tv_sec)*1000000+((t2).tv_usec-(t1).tv_usec))
typedef struct timeval timestruct;
#endif

int main( int argc, char* argv[] )
{
    int n;      /* size of the vector */
    float *a;  /* the vector */
    float *restrict r;  /* the results */
    float *e;  /* expected results */
    float s, c;
    timestruct t1, t2, t3;
    long long cgpu, chost;
    int i, j, nerrors;
    nerrors = 0;
    if( argc > 1 )
        n = atoi( argv[1] );
    else
        n = 1000000;
    if( n <= 0 ) n = 1000000;

    a = (float*)malloc(n*sizeof(float));
    r = (float*)malloc(n*sizeof(float));
    e = (float*)malloc(n*sizeof(float));
    for( i = 0; i < n; ++i ) a[i] = (float)(i+1) * 2.0f;
    /*acc_init( acc_device_nvidia );*/

for(j=0;j<3;++j){
    gettime( &t1 );
    #pragma acc kernels loop
    for( i = 0; i < n; ++i ){
        s = sinf(a[i]);
        c = cosf(a[i]);
        r[i] = s*s + c*c;
    }
    gettime( &t2 );
    cgpu = usec(t1,t2);
    for( i = 0; i < n; ++i ){
        s = sinf(a[i]);
        c = cosf(a[i]);
        e[i] = s*s + c*c;
    }
    gettime( &t3 );
    chost = usec(t2,t3);
    /* check the results */
    for( i = 0; i < n; ++i ) {
        if ( fabsf(r[i] - e[i]) >= 0.000001f ) {
           nerrors++;
        }
    }

    printf( "%13d iterations completed\n", n );
    printf( "%13ld microseconds on GPU\n", cgpu );
    printf( "%13ld microseconds on host\n", chost );
    if ( nerrors != 0 ) {
        printf( "Test FAILED\n");
    } else {
        printf( "Test PASSED\n");
    }
}
    return 0;
}