MATH-989

Added method to check whether a point is within the interpolation range.


git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1491606 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunction.java

@@ -172,6 +172,24 @@ public class BicubicSplineInterpolatingFunction
         return splines[i][j].value(xN, yN);
     }
 
+    /**
+     * Indicates whether a point is within the interpolation range.
+     *
+     * @param x First coordinate.
+     * @param y Second coordinate.
+     * @return {@code true} if (x, y) is a valid point.
+     */
+    public boolean isValidPoint(double x, double y) {
+        if (x < xval[0] ||
+            x > xval[xval.length - 1] ||
+            y < yval[0] ||
+            y > yval[yval.length - 1]) {
+            return false;
+        } else {
+            return true;
+        }
+    }
+
     /**
      * @param x x-coordinate.
      * @param y y-coordinate.

src/test/java/org/apache/commons/math3/analysis/interpolation/BicubicSplineInterpolatingFunctionTest.java

@@ -18,6 +18,7 @@ package org.apache.commons.math3.analysis.interpolation;
 
 import org.apache.commons.math3.exception.DimensionMismatchException;
 import org.apache.commons.math3.exception.MathIllegalArgumentException;
+import org.apache.commons.math3.exception.OutOfRangeException;
 import org.apache.commons.math3.analysis.BivariateFunction;
 import org.apache.commons.math3.distribution.UniformRealDistribution;
 import org.apache.commons.math3.random.RandomGenerator;
@@ -606,4 +607,64 @@ public final class BicubicSplineInterpolatingFunctionTest {
 //             System.out.println();
         }
     }
+
+    @Test
+    public void testIsValidPoint() {
+        final double xMin = -12;
+        final double xMax = 34;
+        final double yMin = 5;
+        final double yMax = 67;
+        final double[] xval = new double[] { xMin, xMax };
+        final double[] yval = new double[] { yMin, yMax };
+        final double[][] f = new double[][] { { 1, 2 },
+                                              { 3, 4 } };
+        final double[][] dFdX = f;
+        final double[][] dFdY = f;
+        final double[][] dFdXdY = f;
+
+        final BicubicSplineInterpolatingFunction bcf
+            = new BicubicSplineInterpolatingFunction(xval, yval, f,
+                                                     dFdX, dFdY, dFdXdY);
+
+        double x, y;
+
+        x = xMin;
+        y = yMin;
+        Assert.assertTrue(bcf.isValidPoint(x, y));
+        // Ensure that no exception is thrown.
+        bcf.value(x, y);
+
+        x = xMax;
+        y = yMax;
+        Assert.assertTrue(bcf.isValidPoint(x, y));
+        // Ensure that no exception is thrown.
+        bcf.value(x, y);
+ 
+        final double xRange = xMax - xMin;
+        final double yRange = yMax - yMin;
+        x = xMin + xRange / 3.4;
+        y = yMin + yRange / 1.2;
+        Assert.assertTrue(bcf.isValidPoint(x, y));
+        // Ensure that no exception is thrown.
+        bcf.value(x, y);
+
+        final double small = 1e-8;
+        x = xMin - small;
+        y = yMax;
+        Assert.assertFalse(bcf.isValidPoint(x, y));
+        // Ensure that an exception would have been thrown.
+        try {
+            bcf.value(x, y);
+            Assert.fail("OutOfRangeException expected");
+        } catch (OutOfRangeException expected) {}
+
+        x = xMin;
+        y = yMax + small;
+        Assert.assertFalse(bcf.isValidPoint(x, y));
+        // Ensure that an exception would have been thrown.
+        try {
+            bcf.value(x, y);
+            Assert.fail("OutOfRangeException expected");
+        } catch (OutOfRangeException expected) {}
+    }
 }