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Polynomials now implement the new UnivariateDifferentiable interface. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1374630 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Luc Maisonobe 2012-08-18 18:09:45 +00:00
parent 09463e6705
commit 63d00ba803
2 changed files with 49 additions and 2 deletions
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25
src/main/java/org/apache/commons/math3/analysis/polynomials/PolynomialFunction.java
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@ -25,6 +25,8 @@ import org.apache.commons.math3.exception.NullArgumentException;
import org.apache.commons.math3.analysis.DifferentiableUnivariateFunction;
import org.apache.commons.math3.analysis.UnivariateFunction;
import org.apache.commons.math3.analysis.ParametricUnivariateFunction;
import org.apache.commons.math3.analysis.differentiation.DerivativeStructure;
import org.apache.commons.math3.analysis.differentiation.UnivariateDifferentiable;
import org.apache.commons.math3.util.FastMath;
import org.apache.commons.math3.util.MathUtils;
@ -36,7 +38,7 @@ import org.apache.commons.math3.util.MathUtils;
*
* @version $Id$
*/
public class PolynomialFunction implements DifferentiableUnivariateFunction, Serializable {
public class PolynomialFunction implements UnivariateDifferentiable, DifferentiableUnivariateFunction, Serializable {
/**
* Serialization identifier
*/
@ -137,6 +139,27 @@ public class PolynomialFunction implements DifferentiableUnivariateFunction, Ser
return result;
}
/** {@inheritDoc}
* @since 3.1
* @throws NoDataException if {@code coefficients} is empty.
* @throws NullArgumentException if {@code coefficients} is {@code null}.
*/
public DerivativeStructure value(final DerivativeStructure t)
throws NullArgumentException, NoDataException {
MathUtils.checkNotNull(coefficients);
int n = coefficients.length;
if (n == 0) {
throw new NoDataException(LocalizedFormats.EMPTY_POLYNOMIALS_COEFFICIENTS_ARRAY);
}
DerivativeStructure result =
new DerivativeStructure(t.getFreeParameters(), t.getOrder(), coefficients[n - 1]);
for (int j = n - 2; j >= 0; j--) {
result = result.multiply(t).add(coefficients[j]);
}
return result;
}
/**
* Add a polynomial to the instance.
*

26
src/main/java/org/apache/commons/math3/analysis/polynomials/PolynomialSplineFunction.java
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@ -21,6 +21,8 @@ import java.util.Arrays;
import org.apache.commons.math3.util.MathArrays;
import org.apache.commons.math3.analysis.DifferentiableUnivariateFunction;
import org.apache.commons.math3.analysis.UnivariateFunction;
import org.apache.commons.math3.analysis.differentiation.DerivativeStructure;
import org.apache.commons.math3.analysis.differentiation.UnivariateDifferentiable;
import org.apache.commons.math3.exception.OutOfRangeException;
import org.apache.commons.math3.exception.NumberIsTooSmallException;
import org.apache.commons.math3.exception.DimensionMismatchException;
@ -61,7 +63,7 @@ import org.apache.commons.math3.exception.util.LocalizedFormats;
*
* @version $Id$
*/
public class PolynomialSplineFunction implements DifferentiableUnivariateFunction {
public class PolynomialSplineFunction implements UnivariateDifferentiable, DifferentiableUnivariateFunction {
/**
* Spline segment interval delimiters (knots).
* Size is n + 1 for n segments.
@ -168,6 +170,28 @@ public class PolynomialSplineFunction implements DifferentiableUnivariateFunctio
return new PolynomialSplineFunction(knots, derivativePolynomials);
}
/** {@inheritDoc}
* @since 3.1
*/
public DerivativeStructure value(final DerivativeStructure t) {
final double t0 = t.getValue();
if (t0 < knots[0] || t0 > knots[n]) {
throw new OutOfRangeException(t0, knots[0], knots[n]);
}
int i = Arrays.binarySearch(knots, t0);
if (i < 0) {
i = -i - 2;
}
// This will handle the case where t is the last knot value
// There are only n-1 polynomials, so if t is the last knot
// then we will use the last polynomial to calculate the value.
if ( i >= polynomials.length ) {
i--;
}
return polynomials[i].value(t.subtract(knots[i]));
}
/**
* Get the number of spline segments.
* It is also the number of polynomials and the number of knot points - 1.