dbeta.cpp

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#include "statsLib.h"

dvariable dbeta( const dvariable& x, const double& shape1, const double& shape2 )
{
  if( x<=0 || x>=1.0 )
  {
    cerr<<"x is <=0 or >=1.0 in "
      "dbeta( const dvariable& x, const double& shape1, const double& shape2 )\n";
    return 0;
  }
  
  if( shape1<=0 || shape2 <=0 )
  {
    cerr<<"shape1 or shape2 is <= 0 in "
      "dbeta( const dvariable& x, const double& shape1, const double& shape2 )\n";
    return 0;
  }
  
  double a=shape1;
  double b=shape2;
  return -1.* gammln(a+b)+(gammln(a)+gammln(b))-(a-1.)*log(x)-(b-1.)*log(1.-x);
}

dvariable dbeta( const dvariable& x, const dvariable& shape1, const dvariable& shape2 )
{
  if( x<=0 || x>=1.0 )
  {
    cerr<<"x is <=0 or >=1.0 in "
      "dbeta( const dvariable& x, const double& shape1, const double& shape2 )\n";
    return 0;
  }
  
  if( shape1<=0 || shape2 <=0 )
  {
    cerr<<"shape1 or shape2 is <= 0 in "
      "dbeta( const dvariable& x, const double& shape1, const double& shape2 )\n";
    return 0;
  }
  
  dvariable a=shape1;
  dvariable b=shape2;
  return -1.* gammln(a+b)+(gammln(a)+gammln(b))-(a-1.)*log(x)-(b-1.)*log(1.-x);
}

dvariable dbeta( const dvariable& x, const prevariable& shape1, const prevariable& shape2 )
{
  if( x<=0 || x>=1.0 )
  {
    cerr<<"x is <=0 or >=1.0 in "
      "dbeta( const dvariable& x, const double& shape1, const double& shape2 )\n";
    return 0;
  }
  
  if( shape1<=0 || shape2 <=0 )
  {
    cerr<<"shape1 or shape2 is <= 0 in "
      "dbeta( const dvariable& x, const double& shape1, const double& shape2 )\n";
    return 0;
  }
  
  dvariable a=shape1;
  dvariable b=shape2;
  return -1.* gammln(a+b)+(gammln(a)+gammln(b))-(a-1.)*log(x)-(b-1.)*log(1.-x);
}