private double logNormalDens(double x,double mean,double stdDev){
  double diff=x - mean;
  return -(diff * diff / (2 * stdDev * stdDev)) - m_normConst - Math.log(stdDev);
}

private double logNormalDens ( double x , double mean , double stdDev ) { double diff = x - mean ; return - ( diff * diff / ( 2 * stdDev * stdDev ) ) - m_normConst - Math . log ( stdDev ) ; }
density function of normal distribution .
