//---------------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define MAX_VALUES 6000
#include <vcl.h>
#pragma hdrstop
////////////////////////使用前 必須對srand(讓其對時間有變化)
///////////////////////n不能等於1
float rand_normal1(void);
void rand_normal2(float* n1, float* n2);
//---------------------------------------------------------------------------
/*
Normal.c-Standard Normal Random Numbers
This program generates random numbers from a standard
normal distribution using a) the central limit theorem,
and b) the Box-Muller algorithm.
*/
#pragma argsused
int main(int argc, char* argv[])
{
float x[MAX_VALUES]; //array containing random nubers
int n; //number of random values required
int i; //loop counter
int choice; //algorithm to be used
float sumx,sumxx; //sum of x and x*x;
float mean,std_dev; //mean and standard deviation
float temp; //temporary storage
printf("\n STANDARD NORMAL RANDOM NUMBER GENERATOR \N");
printf("\n Number of values required:");
scanf("%d",&n);
choice=0;
while (choice<1 || choice >2)
{
printf("\n Select algorithm");
printf("\n \t 1 - Central Limit Theorem");
printf("\n \t 2 - Box Muller");
printf("\n Your choice (1 or 2):");
scanf("%d",&choice);
}
srand((unsigned)time(NULL));
switch (choice)
{
case 1:
for (i=0;i<n;++i)
x[i]=rand_normal1();
break;
case 2:
// for (i=0;i<n/2;i+=2)
for (i=0;i<n;i+=2)
rand_normal2(&x[i],&x[i+1]);
if (n%2!=0)
rand_normal2(&x[n-1],&temp);
//rand_normal2(&x[n],&temp);
break;
}
//print random number - 6 per line
for (i=0;i<n;++i)
{
sumx += x[i];
sumxx+= x[i]*x[i];
printf("%10.6f",x[i]);
}
//compute mean value and standard deviation
sumx=0.0;
sumxx=0.0;
for (i=0;i<n;++i)
{
sumx += x[i];
sumxx+= x[i]*x[i];
}
mean=sumx/n;
std_dev=sqrt((sumxx-n*(mean*mean))/(n-1));
printf("\n\n Mean value =%f",mean);
printf("\n Standard deviation = %f",std_dev);
system("pause");
return 0;
}
//---------------------------------------------------------------------------
/*
Function rand_normal1()
purpose:
Generates random numbers from the standard normal distribution using the Central Limit Theorem
Input Parameters:
None
Output Parameters:
result -standard normal random numbers
Calls:
rand() - C library random number generator
*/
float rand_normal1(void)
{
int i;
int temp;
float result = -6.0;
for (i=0;i<12;++i)
{
temp=rand();
result+=((float)temp/RAND_MAX);
}
return (result);
}
/*Function:rand_normal2(0
Purpose:
Generates random numbers from the standard normal
distribution using the Box Muller algorithm
Input Parameters:
None
Output Parameters:
*n1,*n2 - standard normal random numbers
Calls:
rand() - C library random number generator
*/
void rand_normal2(float *n1,float *n2)
{
float u1,u2,v1,v2,s;
float temp1,temp2;
do{
u1=(float) rand()/RAND_MAX;
u2=(float) rand()/RAND_MAX;
v1=2.*u1-1.0;
v2=2.*u2-1.0;
s=v1*v1+v2*v2;
}while( s>=1.0);
temp1=log(s);
temp2=sqrt(-2.0*temp1/s);
*n1=v1*temp2;
*n2=v2*temp2;
}
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define MAX_VALUES 6000
#include <vcl.h>
#pragma hdrstop
////////////////////////使用前 必須對srand(讓其對時間有變化)
///////////////////////n不能等於1
float rand_normal1(void);
void rand_normal2(float* n1, float* n2);
//---------------------------------------------------------------------------
/*
Normal.c-Standard Normal Random Numbers
This program generates random numbers from a standard
normal distribution using a) the central limit theorem,
and b) the Box-Muller algorithm.
*/
#pragma argsused
int main(int argc, char* argv[])
{
float x[MAX_VALUES]; //array containing random nubers
int n; //number of random values required
int i; //loop counter
int choice; //algorithm to be used
float sumx,sumxx; //sum of x and x*x;
float mean,std_dev; //mean and standard deviation
float temp; //temporary storage
printf("\n STANDARD NORMAL RANDOM NUMBER GENERATOR \N");
printf("\n Number of values required:");
scanf("%d",&n);
choice=0;
while (choice<1 || choice >2)
{
printf("\n Select algorithm");
printf("\n \t 1 - Central Limit Theorem");
printf("\n \t 2 - Box Muller");
printf("\n Your choice (1 or 2):");
scanf("%d",&choice);
}
srand((unsigned)time(NULL));
switch (choice)
{
case 1:
for (i=0;i<n;++i)
x[i]=rand_normal1();
break;
case 2:
// for (i=0;i<n/2;i+=2)
for (i=0;i<n;i+=2)
rand_normal2(&x[i],&x[i+1]);
if (n%2!=0)
rand_normal2(&x[n-1],&temp);
//rand_normal2(&x[n],&temp);
break;
}
//print random number - 6 per line
for (i=0;i<n;++i)
{
sumx += x[i];
sumxx+= x[i]*x[i];
printf("%10.6f",x[i]);
}
//compute mean value and standard deviation
sumx=0.0;
sumxx=0.0;
for (i=0;i<n;++i)
{
sumx += x[i];
sumxx+= x[i]*x[i];
}
mean=sumx/n;
std_dev=sqrt((sumxx-n*(mean*mean))/(n-1));
printf("\n\n Mean value =%f",mean);
printf("\n Standard deviation = %f",std_dev);
system("pause");
return 0;
}
//---------------------------------------------------------------------------
/*
Function rand_normal1()
purpose:
Generates random numbers from the standard normal distribution using the Central Limit Theorem
Input Parameters:
None
Output Parameters:
result -standard normal random numbers
Calls:
rand() - C library random number generator
*/
float rand_normal1(void)
{
int i;
int temp;
float result = -6.0;
for (i=0;i<12;++i)
{
temp=rand();
result+=((float)temp/RAND_MAX);
}
return (result);
}
/*Function:rand_normal2(0
Purpose:
Generates random numbers from the standard normal
distribution using the Box Muller algorithm
Input Parameters:
None
Output Parameters:
*n1,*n2 - standard normal random numbers
Calls:
rand() - C library random number generator
*/
void rand_normal2(float *n1,float *n2)
{
float u1,u2,v1,v2,s;
float temp1,temp2;
do{
u1=(float) rand()/RAND_MAX;
u2=(float) rand()/RAND_MAX;
v1=2.*u1-1.0;
v2=2.*u2-1.0;
s=v1*v1+v2*v2;
}while( s>=1.0);
temp1=log(s);
temp2=sqrt(-2.0*temp1/s);
*n1=v1*temp2;
*n2=v2*temp2;
}
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