Distribution.c

/************************************************************************************
 * Copyright (C) 2023                                                               *
 * TETCOS, Bangalore. India                                                         *
 *                                                                                  *
 * Tetcos owns the intellectual property rights in the Product and its content.     *
 * The copying, redistribution, reselling or publication of any or all of the       *
 * Product or its content without express prior written consent of Tetcos is        *
 * prohibited. Ownership and / or any other right relating to the software and all *
 * intellectual property rights therein shall remain at all times with Tetcos.      *
 *                                                                                  *
 * Author:    Shashi Kant Suman                                                       *
 *                                                                                  *
 * ---------------------------------------------------------------------------------*/
#include "Application.h"
static long double ErrorFun(double p);
/** This function is used to run the distributions */
_declspec(dllexport) int fnDistribution(DISTRIBUTION nDistributionType, double *fDistOut,
        unsigned long *uSeed, unsigned long *uSeed1,double* args)
{
    double fFirstArg = 0.0;
    double fSecondArg = 0.0;
    double fRand = 0.0;
    double fRandomNumber = 0.0;
    int nRandOut = 0;
 
    switch (nDistributionType)
    {
    case Distribution_Exponential: /*Exponential Distribution Function*/
        fFirstArg = args[0];
        nRandOut = fnRandomNo(10000000, &fRand, uSeed, uSeed1);
        fRandomNumber = (double) (fRand);
        fFirstArg = 1 / fFirstArg;
        *fDistOut = (double) -(1 / fFirstArg)
                * (double) logl(1 - fRandomNumber);
        break;
    case Distribution_Uniform: /*Uniform distribution Function*/
        fSecondArg = args[1];
        fFirstArg = args[0];
 
        nRandOut = fnRandomNo(10000000, &fRand, uSeed, uSeed1);
        fRandomNumber = (double) (fRand);
        *fDistOut = fFirstArg + (fSecondArg - fFirstArg) * fRandomNumber;
        break;
    case Distribution_Triangular: /*Triangular Distribution Function*/
        fFirstArg = args[0];
        fSecondArg = args[1];
        nRandOut = fnRandomNo(10000000, &fRand, uSeed, uSeed1);
        fRandomNumber = (double) (fRand);
        if (0 <= fRandomNumber && fRandomNumber <= 0.5) {
            *fDistOut = (double) sqrt(2 * (double) fRandomNumber);
        } else if (fRandomNumber > 0.5 && fRandomNumber <= 1) {
            *fDistOut = 2 - (double) sqrt(2 * (1 - (double) fRandomNumber));
        }
        break;
    case Distribution_Weibull: /*Weibull Distribution Function*/
        fFirstArg = args[0];
        fSecondArg = args[1];
        nRandOut = fnRandomNo(10000000, &fRand, uSeed, uSeed1);
        fRandomNumber = (double) (fRand);
        *fDistOut = (fFirstArg * (double) pow((-(double) logl(1 - (1
                - fRandomNumber))), 1 / fSecondArg));
        break;
    case Distribution_Constant: /*Constant Distribution function*/
        fFirstArg = args[0];
        *fDistOut = fFirstArg;
        break;
    case Distribution_Backlog:/*BackLog Distribution. Not used as of NetSim v7 */ 
        *fDistOut = 0.0;
        break;
 
    case Distribution_Normal:/*Normal Distribution Function on 25-12-2007 by Shashi kant*/
        fFirstArg = args[0]; 
        fSecondArg = args[1];
        nRandOut = fnRandomNo(10000000, &fRand, uSeed, uSeed1);
        fRandomNumber = (double) (fRand);
        *fDistOut = (double) (fFirstArg + fSecondArg * sqrt(2) * ErrorFun(2
                * fRandomNumber - 1));
        break;
    }
    return 1;
}
/** Error inverse Function for Normal Distribution */
static long double ErrorFun(double p)
{
    return (1.0968 * (sqrt(3.1415) * 0.5 * (p + (3.1415 * pow(p, 3)) / 12 + (7
            * pow(3.1415, 2) * pow(p, 5)) / 480 + (127 * pow(3.1415, 3) * pow(
            p, 7)) / 40320)));
}