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 */
 
/* Very simple performance test for the FF_PARFOR
 *
 */
 
#include <cstdlib>
#include <omp.h>
 
#include <ff/parallel_for.hpp>
 
#if defined(USE_TBB)
#include <tbb/tbb.h>
#include <tbb/tbb_thread.h>
#include <tbb/parallel_for.h>
#include <tbb/blocked_range.h>
#include <tbb/task_scheduler_init.h>
#endif
 
/*
 * This random generators are implementing 
 * by following POSIX.1-2001 directives.
 */
#define SIM_RAND_MAX         32767
__thread unsigned long next = 0;
inline static long simRandom(void) {
    next = next * 1103515245 + 12345;
    return((unsigned)(next/65536) % 32768);
}
inline static void simSRandom(unsigned long seed) {
    next = seed;
}
/*
 * In Numerical Recipes in C: The Art of Scientific Computing 
 * (William H. Press, Brian P. Flannery, Saul A. Teukolsky, William T. Vetterling;
 *  New York: Cambridge University Press, 1992 (2nd ed., p. 277))
 */
inline static long simRandomRange(long low, long high) {
    return low + (long) ( ((double) high)* (simRandom() / (SIM_RAND_MAX + 1.0)));
}
 
 
using namespace ff;
 
 
static inline void compute(long id, int nticks) {
    if (next == 0UL) {
        simSRandom(id + 1L);
    }
    long val = simRandomRange(1,nticks);
    for(volatile long k=0;k<val;++k) ;
}
 
int main(int argc, char *argv[]) {
    if (argc<4) {
        printf("use: %s numtasks nworkers ticks [chunk=(numtasks/nworkers)]\n", argv[0]);
        return -1;
    }
    const long numtasks = atol(argv[1]);
    const int  nworkers = atoi(argv[2]);
    const int  nticks   = atoi(argv[3]);
    int   chunk = std::max((int)(numtasks/nworkers),1);
    if (argc == 5) 
        chunk = atoi(argv[4]);
 
    FF_PARFOR_INIT(pf, nworkers);
 
    ffTime(START_TIME);
    FF_PARFOR_START(pf, j,0,numtasks,1, chunk, nworkers) {
        compute(_ff_thread_id, nticks);
    } FF_PARFOR_STOP(pf);
    ffTime(STOP_TIME);
    FF_PARFOR_DONE(pf);
 
    printf("%d Time  = %g (ms)\n", nworkers, ffTime(GET_TIME));
    return 0;
}