org.apache.commons.math3.analysis.integration.gauss

## Class GaussIntegrator

• java.lang.Object
• org.apache.commons.math3.analysis.integration.gauss.GaussIntegrator
• ### Constructor Summary

Constructors
Constructor and Description
GaussIntegrator(double[] points, double[] weights)
Creates an integrator from the given points and weights.
GaussIntegrator(Pair<double[],double[]> pointsAndWeights)
Creates an integrator from the given pair of points (first element of the pair) and weights (second element of the pair.
• ### Method Summary

Methods
Modifier and Type Method and Description
int getNumberOfPoints()
double getPoint(int index)
Gets the integration point at the given index.
double getWeight(int index)
Gets the weight of the integration point at the given index.
double integrate(UnivariateFunction f)
Returns an estimate of the integral of f(x) * w(x), where w is a weight function that depends on the actual flavor of the Gauss integration scheme.
• ### Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
• ### Constructor Detail

• #### GaussIntegrator

public GaussIntegrator(double[] points,
double[] weights)
throws NonMonotonicSequenceException,
DimensionMismatchException
Creates an integrator from the given points and weights. The integration interval is defined by the first and last value of points which must be sorted in increasing order.
Parameters:
points - Integration points.
weights - Weights of the corresponding integration nodes.
Throws:
NonMonotonicSequenceException - if the points are not sorted in increasing order.
DimensionMismatchException - if points and weights don't have the same length
• #### GaussIntegrator

public GaussIntegrator(Pair<double[],double[]> pointsAndWeights)
throws NonMonotonicSequenceException
Creates an integrator from the given pair of points (first element of the pair) and weights (second element of the pair.
Parameters:
pointsAndWeights - Integration points and corresponding weights.
Throws:
NonMonotonicSequenceException - if the points are not sorted in increasing order.
GaussIntegrator(double[], double[])
• ### Method Detail

• #### integrate

public double integrate(UnivariateFunction f)
Returns an estimate of the integral of f(x) * w(x), where w is a weight function that depends on the actual flavor of the Gauss integration scheme. The algorithm uses the points and associated weights, as passed to the constructor.
Parameters:
f - Function to integrate.
Returns:
the integral of the weighted function.
• #### getNumberOfPoints

public int getNumberOfPoints()
Returns:
the order of the integration rule (the number of integration points).
• #### getPoint

public double getPoint(int index)
Gets the integration point at the given index. The index must be in the valid range but no check is performed.
Parameters:
index - index of the integration point
Returns:
the integration point.
• #### getWeight

public double getWeight(int index)
Gets the weight of the integration point at the given index. The index must be in the valid range but no check is performed.
Parameters:
index - index of the integration point
Returns:
the weight.