/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */

/*

 *  (C) 2006 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

/*

 * Check that the timer produces monotone nondecreasing times and that

 * the Tick is reasonable

 */

#include "mpi.h"

#include <stdio.h>

#include "mpitest.h"

static int verbose = 0;

#define MAX_TIMER_TEST 5000

int main(int argc, char *argv[])

{

    double t1[MAX_TIMER_TEST], tick[MAX_TIMER_TEST], tickval;

    double minDiff, maxDiff, diff;

    int i, nZeros = 0;

    int errs = 0;

    MTest_Init(&argc, &argv);

    for (i = 0; i < MAX_TIMER_TEST; i++) {

        t1[i] = MPI_Wtime();

    }

    for (i = 0; i < MAX_TIMER_TEST; i++) {

        tick[i] = MPI_Wtick();

    }

    /* Look at the values */

    /* Look at the tick */

    tickval = MPI_Wtick();

    for (i = 0; i < MAX_TIMER_TEST; i++) {

        if (tickval != tick[i]) {

            fprintf(stderr, "Nonconstant value for MPI_Wtick: %e != %e\n", tickval, tick[i]);

            errs++;

        }

    }

    /* Look at the timer */

    minDiff = 1.e20;

    maxDiff = -1.0;

    nZeros = 0;

    for (i = 1; i < MAX_TIMER_TEST; i++) {

        diff = t1[i] - t1[i - 1];

        if (diff == 0.0)

            nZeros++;

        else if (diff < minDiff)

            minDiff = diff;

        if (diff > maxDiff)

            maxDiff = diff;

    }

    /* Are the time diff values and tick values consistent */

    if (verbose) {

        printf("Tick = %e, timer range = [%e,%e]\n", tickval, minDiff, maxDiff);

        if (nZeros)

            printf("Wtime difference was 0 %d times\n", nZeros);

    }

    MTest_Finalize(errs);

    return MTestReturnValue(errs);

}