/*
 * @(#) smt1_3.c - Random generator quality 'error' function tester
 * (Task 1_3 at the Special Military Training course).
 * (c) 1996 Ivan Maidanski <ivmai@chat.ru> http://ivmai.chat.ru
 * Freeware program source. All rights reserved.
 **
 * Language: ANSI C
 * Tested with: Borland C++ v3.1
 * Last modified: 1996-12-09 10:15:00 GMT+03:00
 */

#include <stdio.h>
#include <math.h>

#define K 12

int m[1000];

int rnd_func(int x)
{
 return (x*5%(1<<K));
}

double norm_rnd_func(int n, double mx, double sigmax,int *seed)
{
 int i;
 long ksi=0;
 double z;
 for (i=0;i<n;i++)
  ksi+=(*seed=rnd_func(*seed));
 z=(2.0*ksi/(1<<K)-n)*sqrt(3.0/n);
 return ((z-(3.0+(1.0-z*z)*z)/n/20)*sigmax+mx);
}

double erf_func(double x)
{
 int n=0;
 double arg,res,last;
 arg=res=x;
 x=-x*x;
 do
 {
  last=res;
  arg=arg*x/(++n);
  res+=arg/(n+n+1);
 } while (res!=last);
 return (res*M_2_SQRTPI);
}

int main()
{
 int seed,n,q,s,i;
 double x,p,delta,chi,chi_alfa;
 printf("Input K (amount of intervals):\n");
 scanf("%d",&n);
 printf("Input N (amount of generated numbers):\n");
 scanf("%d",&q);
 printf("Input n (amount of ksi):\n");
 scanf("%d",&s);
 printf("Input random seed [%d..%d],odd:\n",(1<<(K-2))-1,(1<<K)-1);
 scanf("%d",&seed);
 printf("Input Chi^2(alfa,r):\n");
 scanf("%lf",&chi_alfa);
 for (i=0;i<n;i++)
  m[i]=0;
 for (i=0;i<q;i++)
  if ((x=(norm_rnd_func(s,0,1,&seed)+3)/6)>0 && x<1)
   m[(int)(x*n)]++;
 chi=0.0;
 x=-3.0/sqrt(2);
 delta=3.0*sqrt(2)/n;
 for (i=0;i<n;i++)
 {
  p=(erf_func(x+delta)-erf_func(x))/2;
  chi+=(m[i]-q*p)*(m[i]-q*p)/q/p;
  x+=delta;
  printf("%5d:%5d\n",i+1,m[i]);
 }
 printf("Chi^2: %lf\n",chi);
 printf(chi<chi_alfa? "Accepted\n" : "NOT ACCEPTED\n");
 return 0;
}