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Unit tests. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1488256 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Gilles Sadowski 2013-05-31 14:41:52 +00:00
parent 1fc99654bd
commit 94c9d2e023
1 changed files with 164 additions and 0 deletions
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164
src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java
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@ -19,6 +19,9 @@ package org.apache.commons.math3.analysis.interpolation;
import org.apache.commons.math3.exception.DimensionMismatchException; import org.apache.commons.math3.exception.DimensionMismatchException;
import org.apache.commons.math3.exception.MathIllegalArgumentException; import org.apache.commons.math3.exception.MathIllegalArgumentException;
import org.apache.commons.math3.analysis.BivariateFunction; import org.apache.commons.math3.analysis.BivariateFunction;
import org.apache.commons.math3.distribution.UniformRealDistribution;
import org.apache.commons.math3.random.RandomGenerator;
import org.apache.commons.math3.random.Well19937c;
import org.junit.Assert; import org.junit.Assert;
import org.junit.Test; import org.junit.Test;
import org.junit.Ignore; import org.junit.Ignore;
@ -444,4 +447,165 @@ public final class BicubicSplineInterpolatingFunctionTest {
} }
} }
} }
/**
* Interpolating a plane.
* <p>
* z = 2 x - 3 y + 5
*/
@Test
public void testInterpolation1() {
final int sz = 21;
double[] xval = new double[sz];
double[] yval = new double[sz];
// Coordinate values
final double delta = 1d / (sz - 1);
for (int i = 0; i < sz; i++) {
xval[i] = -1 + 15 * i * delta;
yval[i] = -20 + 30 * i * delta;
}
// Function values
BivariateFunction f = new BivariateFunction() {
public double value(double x, double y) {
return 2 * x - 3 * y + 5;
}
};
double[][] zval = new double[xval.length][yval.length];
for (int i = 0; i < xval.length; i++) {
for (int j = 0; j < yval.length; j++) {
zval[i][j] = f.value(xval[i], yval[j]);
}
}
// Partial derivatives with respect to x
double[][] dZdX = new double[xval.length][yval.length];
for (int i = 0; i < xval.length; i++) {
for (int j = 0; j < yval.length; j++) {
dZdX[i][j] = 2;
}
}
// Partial derivatives with respect to y
double[][] dZdY = new double[xval.length][yval.length];
for (int i = 0; i < xval.length; i++) {
for (int j = 0; j < yval.length; j++) {
dZdY[i][j] = -3;
}
}
// Partial cross-derivatives
double[][] dZdXdY = new double[xval.length][yval.length];
for (int i = 0; i < xval.length; i++) {
for (int j = 0; j < yval.length; j++) {
dZdXdY[i][j] = 0;
}
}
final BivariateFunction bcf
= new BicubicSplineInterpolatingFunction(xval, yval, zval,
dZdX, dZdY, dZdXdY);
double x, y;
double expected, result;
final RandomGenerator rng = new Well19937c(1234567L); // "tol" depends on the seed.
final UniformRealDistribution distX
= new UniformRealDistribution(xval[0], xval[xval.length - 1]);
final UniformRealDistribution distY
= new UniformRealDistribution(yval[0], yval[yval.length - 1]);
final int numSamples = 50;
final double tol = 6;
for (int i = 0; i < numSamples; i++) {
x = distX.sample();
for (int j = 0; j < numSamples; j++) {
y = distY.sample();
// System.out.println(x + " " + y + " " + f.value(x, y) + " " + bcf.value(x, y));
Assert.assertEquals(f.value(x, y), bcf.value(x, y), tol);
}
// System.out.println();
}
}
/**
* Interpolating a paraboloid.
* <p>
* z = 2 x<sup>2</sup> - 3 y<sup>2</sup> + 4 x y - 5
*/
@Test
public void testInterpolation2() {
final int sz = 21;
double[] xval = new double[sz];
double[] yval = new double[sz];
// Coordinate values
final double delta = 1d / (sz - 1);
for (int i = 0; i < sz; i++) {
xval[i] = -1 + 15 * i * delta;
yval[i] = -20 + 30 * i * delta;
}
// Function values
BivariateFunction f = new BivariateFunction() {
public double value(double x, double y) {
return 2 * x * x - 3 * y * y + 4 * x * y - 5;
}
};
double[][] zval = new double[xval.length][yval.length];
for (int i = 0; i < xval.length; i++) {
for (int j = 0; j < yval.length; j++) {
zval[i][j] = f.value(xval[i], yval[j]);
}
}
// Partial derivatives with respect to x
double[][] dZdX = new double[xval.length][yval.length];
BivariateFunction dfdX = new BivariateFunction() {
public double value(double x, double y) {
return 4 * (x + y);
}
};
for (int i = 0; i < xval.length; i++) {
for (int j = 0; j < yval.length; j++) {
dZdX[i][j] = dfdX.value(xval[i], yval[j]);
}
}
// Partial derivatives with respect to y
double[][] dZdY = new double[xval.length][yval.length];
BivariateFunction dfdY = new BivariateFunction() {
public double value(double x, double y) {
return 4 * x - 6 * y;
}
};
for (int i = 0; i < xval.length; i++) {
for (int j = 0; j < yval.length; j++) {
dZdY[i][j] = dfdY.value(xval[i], yval[j]);
}
}
// Partial cross-derivatives
double[][] dZdXdY = new double[xval.length][yval.length];
for (int i = 0; i < xval.length; i++) {
for (int j = 0; j < yval.length; j++) {
dZdXdY[i][j] = 4;
}
}
BivariateFunction bcf = new BicubicSplineInterpolatingFunction(xval, yval, zval,
dZdX, dZdY, dZdXdY);
double x, y;
double expected, result;
final RandomGenerator rng = new Well19937c(1234567L); // "tol" depends on the seed.
final UniformRealDistribution distX
= new UniformRealDistribution(rng, xval[0], xval[xval.length - 1]);
final UniformRealDistribution distY
= new UniformRealDistribution(rng, yval[0], yval[yval.length - 1]);
final double tol = 224;
double max = 0;
for (int i = 0; i < sz; i++) {
x = distX.sample();
for (int j = 0; j < sz; j++) {
y = distY.sample();
// System.out.println(x + " " + y + " " + f.value(x, y) + " " + bcf.value(x, y));
Assert.assertEquals(f.value(x, y), bcf.value(x, y), tol);
}
// System.out.println();
}
}
} }