org.apache.commons.numbers.gamma.Policy Maven / Gradle / Ivy
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.commons.numbers.gamma;
/**
* Encapsulate the policy for function evaluation.
* This is a reduced implementation of the Boost {@code boost::math::policies}
* functionality. No settings are preserved for the error handling policy or
* promotion of data types for computations.
* This controls the convergence criteria and maximum iterations for series evaluations.
*
* @see
* Policies: Controlling Precision, Error Handling etc
*/
final class Policy {
/** Default policy. The Boost default uses 2^-52 for the epsilon. This uses
* 2^-53 to use an extra guard digit in the Kahan series summations.
* The minimum value for the Commons continued fraction epsilon is also 2^-53. */
private static final Policy DEFAULT = new Policy(0x1.0p-53, 1000000);
/** Epsilon value for relative error. */
private final double eps;
/** The maximum number of iterations permitted in a series evaluation. */
private final int maxIterations;
/**
* Instantiates a new policy.
*
* @param eps the eps
* @param maxIterations the maximum number of iterations permitted in a series
* evaluation
*/
Policy(double eps, int maxIterations) {
this.eps = eps;
this.maxIterations = maxIterations;
}
/**
* Gets the default.
*
* @return the default policy
*/
static Policy getDefault() {
return DEFAULT;
}
/**
* Gets the epsilon value for relative error.
*
* @return the epsilon
*/
double getEps() {
return eps;
}
/**
* Gets the maximum number of iterations permitted in a series evaluation.
*
* @return max iterations
*/
int getMaxIterations() {
return maxIterations;
}
}