GaussIntegrator (Apache Commons Math 3.6.1 API)

java.lang.Object
- org.apache.commons.math3.analysis.integration.gauss.GaussIntegrator

Direct Known Subclasses:

SymmetricGaussIntegrator
```
public class GaussIntegrator
extends Object
```
Class that implements the Gaussian rule for integrating a weighted function.

Since:

3.1

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.
    See Also:
    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.

Class GaussIntegrator

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

GaussIntegrator

GaussIntegrator

Method Detail

integrate

getNumberOfPoints

getPoint

getWeight