Java Probability类代码示例

import cern.jet.stat.Probability; //导入依赖的package包/类
@Override
public void computeMissingParameterAfterSim()
{
	// Only compute for numSamples > 1
	// (Student's t-distribution only defined for v > 0)
	if (numSamples > 1) {
		double prob, x;
		x = width * Math.sqrt(numSamples / varEstimator);
		// Note: need to hard-code case x=Inf
		if (Double.isInfinite(x)) {
			prob = 1.0;
		}
		// (Note: Colt's studentT seems to break for v=1 so do manually)
		else if (numSamples - 1 > 1) {
			prob = Probability.studentT(x, numSamples - 1);
		} else {
			// PDF for v=1 is 1/2 + arctan(x)/pi
			prob = 0.5 + Math.atan(x) / Math.PI;
		}
		confidence = 2 * (1.0 - prob);
		missingParameterComputed = true;
	}
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
@Override
public void computeMissingParameterAfterSim()
{
	double quantile;
	// Only compute for numSamples > 1
	// (Student's t-distribution only defined for v > 0)
	if (numSamples > 1) {
		// (Note: Colt's studentTinverse seems to break for v=1 so do manually)
		if (numSamples - 1 > 1) {
			quantile = Probability.studentTInverse(confidence, numSamples - 1);
		} else {
			// PDF for v=1 is 1/2 + arctan(x)/pi
			// Want x for pdf = 1-conf/2 
			quantile = Math.tan((0.5 - confidence / 2) * Math.PI);
		}
		width = quantile * Math.sqrt(varEstimator / numSamples);
		missingParameterComputed = true;
	}
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
protected double binomialSampleEquality(double X1, double X2, double n1, double n2){
	double P1 = X1/n1;
	double P2 = X2/n2;
	double P = (X1+X2)/(n1+n2);
	double Z = (P1-P2)/(Math.sqrt(P*(1-P)*((1/n1)+(1/n2))));
	if(!Double.isNaN(Z))
		return(1-Probability.normal(Z));
	else
		return(-1);
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
@Override
public boolean shouldStopNow(int iters, Sampler sampler)
{
	double quantile = 0.0;

	// Need at least 2 iterations
	// (Student's t-distribution only defined for v > 1)
	// (and variance is always 0 for iters = 1)
	if (iters < 2)
		return false;

	// We cannot conclude yet whether it is a "S^2=0" case or if the estimator is still valid (i.e. std error > 0)
	if (sampler.getVariance() <= 0.0) {
		// automatic
		if (!reqIterToConcludeGiven && maxReward / width > iters)
			return false;
		// "manual"
		if (reqIterToConcludeGiven && reqIterToConclude > iters)
			return false;
	}

	// The required number of iterations for the expected confidence is not reached yet
	quantile = Probability.normalInverse(1.0 - confidence / 2.0);
	squaredQuantile = quantile * quantile;
	if (sampler.getVariance() > 0.0 && (iters + 1) < sampler.getVariance() * squaredQuantile / (width * width))
		return false;

	// Store final number of iterations (to compute missing parameter later)
	computedIterations = iters;
	return true;
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
@Override
public boolean shouldStopNow(int iters, Sampler sampler)
{
	double quantile = 0.0;

	// Need at least 2 iterations
	// (Student's t-distribution only defined for v > 0)
	// (and variance is always 0 for iters = 1)
	if (iters < 2)
		return false;

	// We cannot conclude yet whether it is a "S^2=0" case or if the estimator is still valid (i.e. std error > 0)
	if (sampler.getVariance() <= 0.0) {
		// automatic
		if (!reqIterToConcludeGiven && maxReward / width > iters)
			return false;
		// "manual"
		if (reqIterToConcludeGiven && reqIterToConclude > iters)
			return false;
	}

	// See if required number of iterations for the expected confidence is reached yet
	// (Note: Colt's studentTinverse seems to break for v=1 so do manually)
	if (iters - 1 > 1) {
		quantile = Probability.studentTInverse(confidence, iters - 1);
	} else {
		// PDF for v=1 is 1/2 + arctan(x)/pi
		// Want x for pdf = 1-conf/2 
		quantile = Math.tan((0.5 - confidence / 2) * Math.PI);
	}
	squaredQuantile = quantile * quantile;
	if (sampler.getVariance() > 0.0 && iters < sampler.getVariance() * squaredQuantile / (width * width))
		return false;

	// Store final number of iterations (to compute missing parameter later)
	computedIterations = iters;
	return true;
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
/**
 * {@inheritDoc}
 */
@Override
public double getInverseCDF(final Double p) {
  Validate.notNull(p);
  Validate.isTrue(p >= 0 && p <= 1, "Probability must be >= 0 and <= 1");
  return Probability.normalInverse(p);
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
public static double pValueForTstat(double tstat, int df)
        throws ExtensionException {
  // Returns the P value of the T statistic tstat with df degrees of
  // freedom. This is a two-tailed test so we just double the right
  // tail which is given by studentT of -|tstat|.

  double x = Math.abs(tstat);
  try {
    double p = Probability.studentT((double) df, -x);
    return 2.0 * p;
  } catch (IllegalArgumentException | ArithmeticException ex) {
    throw new ExtensionException("colt .studentT reports: " + ex);
  }
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
public static double getStudentArea(double x, int df)
        throws ExtensionException {
  // Returns the area to the left of x in the Student T distribution
  // with the given degrees of freedom.
  try {
    return Probability.studentT((double) df, x);
  } catch (IllegalArgumentException | ArithmeticException ex) {
    throw new ExtensionException("colt .studentT reports: " + ex);
  }
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
public static double getNormalArea(double x, double mean, double sd)
        throws ExtensionException {
  // Returns the area to the left of x in the normal distribution
  // with the given mean and standard deviation.
  try {
    return Probability.normal(mean, sd, x);
  } catch (IllegalArgumentException | ArithmeticException ex) {
    throw new ExtensionException("colt .normal reports: " + ex);
  }
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
public static double getStudentTInverse(double x, int df)
        throws ExtensionException {
  // Returns the value, t, for which the area under the Student-t 
  // probability density function (integrated from minus infinity to t) 
  // is equal to x.
  double a = 2.0 * (1.0 - x);
  try {
    return Probability.studentTInverse(a, df);
  } catch (IllegalArgumentException | ArithmeticException ex) {
    throw new ExtensionException("colt .studentTInverse reports: " + ex);
  }
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
public static double getNormalInverse(double area, double mean, double sd)
        throws ExtensionException {
  // Returns the x in the normal distribution with the given mean and
  // standard deviation, to the left of which lies the given area.
  // normal.Inverse returns the value in terms of standard deviations
  // from the mean, so we need to adjust it for the given mean and 
  // standard deviation.
  try {
    double x = Probability.normalInverse(area);
    return (x + mean) * sd;
  } catch (IllegalArgumentException | ArithmeticException ex) {
    throw new ExtensionException("colt .normalInverse reports: " + ex);
  }
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
public static double getBinomialComplemented(int n, int k, double p)
        throws ExtensionException {
  // Returns the sum of the terms k+1 through n of the Binomial 
  // probability density, where n is the number of trials and P is
  // the probability of success in the range 0 to 1.
  try {
    return Probability.binomialComplemented(k, n, p);
  } catch (IllegalArgumentException | ArithmeticException ex) {
    throw new ExtensionException("colt .binomialComplement reports: " + ex);
  }
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
public static double getChiSquare(double x, double df)
        throws ExtensionException {
  // Returns the area under the left hand tail (from 0 to x) of the 
  // Chi square probability density function with df degrees of freedom.
  try {
    return Probability.chiSquare(df, x);
  } catch (IllegalArgumentException | ArithmeticException ex) {
    throw new ExtensionException("colt .chiSquare reports: " + ex);
  }
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
public static double getChiSquareComplemented(double x, double df)
        throws ExtensionException {
  // Returns the area under the right hand tail (from x to infinity) 
  // of the Chi square probability density function with df degrees 
  // of freedom.
  try {
    return Probability.chiSquareComplemented(df, x);
  } catch (IllegalArgumentException | ArithmeticException ex) {
    throw new ExtensionException("colt .chiSquareComplemented reports: " + ex);
  }
}
 

import cern.jet.stat.Probability; //导入依赖的package包/类
protected double binomialSampleEquality(double X1, double X2, double n1, double n2){
    double P1 = X1/n1;
    double P2 = X2/n2;
    double P = (X1+X2)/(n1+n2);
    double Z = (P1-P2)/(Math.sqrt(P*(1-P)*((1/n1)+(1/n2))));
    if(!Double.isNaN(Z)){
	double prob = Probability.normal(Z);
	if(prob>0.5)
	    return(1-prob);
	else
	    return(prob);
    }else{
	return(-1);
    }
}