Simularea secvențială prin planificare de evenimente într-un limbaj procedural - ANSI C

Programul C este construit ca proiect compus din doua fisiere sursa, "sp.c" si "rndevg.c". Acesta din urma contine rutine pentru generarea distributiilor statistice, ale caror prototipuri sunt definite în fisierul header "rndevg.h".

Fisierul "rndev.h":

#include <math.h>

#include <stdlib.h>

#include <time.h>

#define MaxReal 1.0E30

#define SEC_D 86400

#ifndef M_PI

#define M_PI 3.1416

#endif

void Randomize(void);

double Expon(double);

double Norml(double,double);

Fisierul "rndevg.c":

#include "rndevg.h"

#include <stdio.h>

void Randomize(void)

{

time_t *t;

long Randseed=time(t) % SEC_D;

srand(Randseed);

printf("Randseed=%ldnn",Randseed);

}

double Expon(Med);

double Med;

{ /* return ( Med * log((double)(rand())/RAND_MAX));*/

int r;

double rd;

r=rand();

if (r != 0) rd=(double)(r);

else rd=(double)(r+1);

return( Med*log(rd/RAND_MAX));

}

double Norml(Med, Sigma);

double Med, Sigma;

{

double E1, N1;

/*Randomize();*/

E1 = Expon(Med);

/*Randomize();*/

N1 = sqrt(2 * E1) * cos(2 * M_PI * (double)(rand())/RAND_MAX);

return (Sigma * N1 + Med);

}

Fisierul "sp.c":

/* ANSI version, with user-constructed Randomize */

#include <stdio.h>

#include "rndevg.h"

#define NumEv 2

#define NMax 500

static double tmis, tms, sigma, tue, b, s, clck;

static long ncl, lqt, lst, mq, f, np, imev;

static double tsclq[NMax];

static double lev[NumEv];

static void INIT()

{

clck = 0.0; imev = 0; lqt = 0; lst = 0; tue = 0.0;

b = 0.0; mq = 0; s = 0.0; f = 0; np = 0;

Randomize();

lev[0] = clck + Expon(tmis);

lev[1] = MaxReal;

}

static void AVANST()

{

long i;

double fmin = MaxReal;

imev = 0; i = 1;

while (i <= NumEv && lev[i 1] <= fmin) {

fmin = lev[i 1];

imev = i;

i++;

}

if (imev == 0) printf("*** ERR.1: Empty Future Event List");

else clck = lev[imev 1];

}

static void SOSIRE()

{

long i;

double ts, tis;

if (lst != 1) {

lst = 1;

tsclq[0] = clck;

ts = Norml(tms, sigma);

lev[1] = clck + ts;

tue = clck;

if (lqt > mq) mq = lqt;

} else {