Testing Random Number Generators

Listing 3: ChiSqFrq.c

/* ============ */
/* ChiSqFrq.c   */
/* ============ */
/* -------------------------------- */
/* WorkArea is defined in freqtst.c */
/* -------------------------------- */
#define Freq    WorkArea
/* ====================================================== */
/* ChiSqFreq - Calculates Chi-Square Value of Frequencies */
/* ====================================================== */
void
ChiSqFreq(CHISQ_STRU * ChiSqData)
{
     ULONG   i, MaxNums, MaxSize;

    double  SosFreq = 0;

    /* --------------------------------------- */
    /* RandFun is assumed to produce uniformly */
    /* distributed random numbers in [0,32767] */
    /* --------------------------------------- */

    MaxSize = (ULONG)ChiSqData->NumElements;
    MaxNums = ChiSqData->NumVariates;
    for (i = 0; i < MaxSize; ++i)
    {
        Freq[i] = 0;
    }

    /* --------------------------------------- */
    /* Collect Data for Chi-Square Calculation */
    /* --------------------------------------- */
    for (i = 0; i < MaxNums; ++i)
    {
        int     NewRand;

        NewRand = (int)(ChiSqData->RandFun() % (int)MaxSize);
        ++Freq[NewRand];
    }

    /* --------------------------- */
    /* Counting Variates Generated */
    /* --------------------------- */
    ChiSqData->TotNumGen += MaxNums;

    /* ---------------------------------------- */
    /* Calculate Sums of Squares of Frequencies */
    /* ---------------------------------------- */
    for (i = 0; i < MaxSize; ++i)
    {
        SosFreq += SQR((double) Freq[i]);
    }

    /* -------------------------- */
    /* Calculate Chi-Square Value */
    /* -------------------------- */
    ChiSqData->ChiSqValu = (SosFreq / (double) MaxNums) *
        (double) MaxSize - (double) MaxNums;
}
/* End of File */