Author: erans
Date: Fri May 31 14:41:52 2013
New Revision: 1488256
URL: http://svn.apache.org/r1488256
Log:
Unit tests.
Modified:
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java
Modified:
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java?rev=1488256&r1=1488255&r2=1488256&view=diff
==============================================================================
---
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java
(original)
+++
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java
Fri May 31 14:41:52 2013
@@ -19,6 +19,9 @@ package org.apache.commons.math3.analysi
import org.apache.commons.math3.exception.DimensionMismatchException;
import org.apache.commons.math3.exception.MathIllegalArgumentException;
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.Test;
import org.junit.Ignore;
@@ -444,4 +447,165 @@ public final class BicubicSplineInterpol
}
}
}
+
+ /**
+ * 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();
+ }
+ }
}
