xcsmacros.c

Simple GA code (Pascal code from Goldberg, D. E. (1989), Genetic Algorithms in Search, Optimization,

/*
/       (XCS-C 1.2)
/	------------------------------------
/	Learning Classifier System based on accuracy
/
/     by 
/     Martin V. Butz
/     Illinois Genetic Algorithms Laboratory (IlliGAL)
/     University of Illinois at Urbana/Champaign
/     [e-mail]
/
/     Last modified: 09-30-2003
/
/     Utility functions like random number generator and double/int/string conversion.
*/

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

#include "xcsMacros.h"

long _Q = _M/_A;     /* M / A */
long _R = _M%_A;     /* M mod A */
long _seed;          /* a number between 1 and m-1 */
int haveUniNum=0;
double uniNum=0;

/* returns a floating-point random number generated according to uniform distribution from [0,1) */
double urand()
{
  long lo,hi,test;
  
  hi   = _seed / _Q;
  lo   = _seed % _Q;
  test = _A*lo - _R*hi;
  
  if (test>0)
    _seed = test;
  else
    _seed = test+_M;

  return (double)(_seed)/_M;
}

/* returns a floating-point random number generated according to a normal distribution with 
 * mean 0 and standard deviation 1 */
double nrand()
{
  float x1, x2, w;

  if(haveUniNum){
    haveUniNum=0;
    return uniNum;
  }else{
    do {
      x1 = 2.0 * urand() - 1.0;
      x2 = 2.0 * urand() - 1.0;
      w = x1 * x1 + x2 * x2;
    } while ( w >= 1.0 );
    
    w = sqrt( (-2.0 * log( w ) ) / w );
    uniNum = x1 * w;
    haveUniNum=1;
    return x2 * w;
  }
  
}

/* sets the random seed */
long  setSeed(long newSeed)
{
  return (_seed = newSeed);
}

/**
 * randomizes the pseudo random generator 
 */
void randomize(void)
{
  setSeed((long)(time(NULL)%10000+1));
}

/**
 * returns int value of string - does not check for any incorrect format
 */
int getIntValue(char *string)
{
  int i, l, value=0;
  l = strlen(string);
  for(i=0; i<l; i++){
    if(string[i]=='.' || string[i]==',')
      break;
    value = value*10 + (int)string[i]-(int)('0');
  }
  return value;
}

/**
 * returns double value of string - does not check for any incorrect format! 
 */
double getDoubleValue(char *string)
{
  int i, l;
  double value=0., divider=0;

  l = strlen(string);
  for(i=0; i<l; i++){
    if(string[i]=='.' || string[i]==',')
      divider = 10.;
    else if(divider==0)
      value = value*10. + (double)((int)string[i]-(int)('0'));
    else{
      value += (double)((int)string[i]-(int)('0'))/divider;
      divider*=10.;
    }
  }
  return value;
}