Broke the 2D splines into their own classes

src/main/java/com/wildbitsfoundry/etk4j/math/interpolation/BiCubicSpline.java

@@ -0,0 +1,50 @@
+package com.wildbitsfoundry.etk4j.math.interpolation;
+
+import java.util.Arrays;
+
+public class BiCubicSpline extends Spline2D {
+
+    protected BiCubicSpline(double[] y, Spline[] splines, int order) {
+        super(y, splines, order);
+    }
+
+    /**
+     * Construct a bicubic spline using not-a-knot conditions.
+     *
+     * @param x The x coordinates of the spline.
+     * @param y The y coordinates of the spline.
+     * @param z The values of the spline at each {@code (x, y)}. Notice that for each x and y combination there should
+     *          be a value in {@code z}. For example, consider: <br>
+     *
+     * {@code x = [1, 2, 3, 4]}, {@code y = [1, 2, 3, 4]}, <br>and {@code z(x, y) = x<sup>2</sup> * y<sup>2</sup>}. <br>
+     *          This means that the first row of {@code z} will be all the values obtained by fixing {@code x = 1} and
+     *          iterating over all the values of {@code y}. <br>
+     *          {@code z[0] = [z(1, 1), z(1, 2), z(1, 3), z(1, 4)}; <br>
+     *          Similarly: <br>
+     *          {@code z[1] = [z(2, 1), z(2, 2), z(2, 3), z(2, 4)}; <br>
+     *          and so on. <br>
+     *          Even though internally we iterate over {@code x} and {@code y} multiple times, only a single copy of
+     *          each {@code (x, y)} is required while. Please refer to the example in {@link examples.Spline2DExample}.
+     *
+     * @return A bicubic spline.
+     */
+    public static Spline2D newBicubicSpline(double[] x, double[] y, double[][] z) {
+        final int rows = y.length;
+        final int cols = x.length;
+        final int order = 4;
+
+        if (z.length != y.length) {
+            throw new IllegalArgumentException("The length of z has to be the same length as y.");
+        }
+
+        double[] yt = Arrays.copyOf(y, rows);
+        Spline[] splines = new Spline[rows];
+        for (int i = 0; i < rows; ++i) {
+            if (cols != z[i].length) {
+                throw new IllegalArgumentException("The length of each array in z has to be the same.");
+            }
+            splines[i] = CubicSpline.newCubicSplineInPlace(x, z[i]);
+        }
+        return new BiCubicSpline(yt, splines, order);
+    }
+}

src/main/java/com/wildbitsfoundry/etk4j/math/interpolation/BiLinearSpline.java

@@ -0,0 +1,53 @@
+package com.wildbitsfoundry.etk4j.math.interpolation;
+
+import examples.Spline2DExample;
+
+import java.util.Arrays;
+
+public class BiLinearSpline extends Spline2D {
+
+    protected BiLinearSpline(double[] y, Spline[] splines, int order) {
+        super(y, splines, order);
+    }
+
+    /**
+     * Construct a bilinear spline using not-a-knot conditions.
+     *
+     * @param x The x coordinates of the spline.
+     * @param y The y coordinates of the spline.
+     * @param z The values of the spline at each {@code (x, y)}. Notice that for each x and y combination there should
+     *          be a value in {@code z}. For example, consider: <br>
+     *
+     * {@code x = [1, 2, 3, 4]}, {@code y = [1, 2, 3, 4]}, <br>and {@code z(x, y) = x<sup>2</sup> * y<sup>2</sup>}. <br>
+     *          This means that the first row of {@code z} will be all the values obtained by fixing {@code x = 1} and
+     *          iterating over all the values of {@code y}. <br>
+     *          {@code z[0] = [z(1, 1), z(1, 2), z(1, 3), z(1, 4)}; <br>
+     *          Similarly: <br>
+     *          {@code z[1] = [z(2, 1), z(2, 2), z(2, 3), z(2, 4)}; <br>
+     *          and so on. <br>
+     *          Even though internally we iterate over {@code x} and {@code y} multiple times, only a single copy of
+     *          each {@code (x, y)} is required while. Please refer to the example in {@link Spline2DExample}.
+     *
+     * @return A bilinear spline.
+     */
+    public static Spline2D newBilinearSpline(double[] x, double[] y, double[][] z) {
+        final int rows = y.length;
+        final int cols = x.length;
+        final int order = 2;
+
+        if (z.length != y.length) {
+            throw new IllegalArgumentException("The length of z has to be the same length as y.");
+        }
+
+        double[] yt = Arrays.copyOf(y, rows);
+        Spline[] splines = new Spline[rows];
+        for (int i = 0; i < rows; ++i) {
+            if (cols != z[i].length) {
+                throw new IllegalArgumentException("The length of each array in z has to be the same.");
+            }
+            splines[i] = LinearSpline.newLinearSplineInPlace(x, z[i]);
+        }
+        return new BiLinearSpline(yt, splines, order);
+    }
+
+}

src/main/java/com/wildbitsfoundry/etk4j/math/interpolation/Spline2D.java

@@ -8,7 +8,7 @@
 /**
  * The {@code Spline2D} class represents bicubic and bilinear interpolation using cubic and linear splines respectively.
  */
-public class Spline2D implements BivariateFunction {
+public abstract class Spline2D implements BivariateFunction {
 
     private double[] y;
     private Spline[] splines;
@@ -21,86 +21,6 @@ protected Spline2D(double[] y, Spline[] splines, int order) {
         this.splines = splines;
     }
 
-    /**
-     * Construct a bicubic spline using not-a-knot conditions.
-     *
-     * @param x The x coordinates of the spline.
-     * @param y The y coordinates of the spline.
-     * @param z The values of the spline at each {@code (x, y)}. Notice that for each x and y combination there should
-     *          be a value in {@code z}. For example, consider: <br>
-     *
-     * {@code x = [1, 2, 3, 4]}, {@code y = [1, 2, 3, 4]}, <br>and {@code z(x, y) = x<sup>2</sup> * y<sup>2</sup>}. <br>
-     *          This means that the first row of {@code z} will be all the values obtained by fixing {@code x = 1} and
-     *          iterating over all the values of {@code y}. <br>
-     *          {@code z[0] = [z(1, 1), z(1, 2), z(1, 3), z(1, 4)}; <br>
-     *          Similarly: <br>
-     *          {@code z[1] = [z(2, 1), z(2, 2), z(2, 3), z(2, 4)}; <br>
-     *          and so on. <br>
-     *          Even though internally we iterate over {@code x} and {@code y} multiple times, only a single copy of
-     *          each {@code (x, y)} is required while. Please refer to the example in {@link examples.Spline2DExample}.
-     *
-     * @return A bicubic spline.
-     */
-    public static Spline2D newBicubicSpline(double[] x, double[] y, double[][] z) {
-        final int rows = y.length;
-        final int cols = x.length;
-        final int order = 4;
-
-        if (z.length != y.length) {
-            throw new IllegalArgumentException("The length of z has to be the same length as y.");
-        }
-
-        double[] yt = Arrays.copyOf(y, rows);
-        Spline[] splines = new Spline[rows];
-        for (int i = 0; i < rows; ++i) {
-            if (cols != z[i].length) {
-                throw new IllegalArgumentException("The length of each array in z has to be the same.");
-            }
-            splines[i] = CubicSpline.newCubicSplineInPlace(x, z[i]);
-        }
-        return new Spline2D(yt, splines, order);
-    }
-
-    /**
-     * Construct a bilinear spline using not-a-knot conditions.
-     *
-     * @param x The x coordinates of the spline.
-     * @param y The y coordinates of the spline.
-     * @param z The values of the spline at each {@code (x, y)}. Notice that for each x and y combination there should
-     *          be a value in {@code z}. For example, consider: <br>
-     *
-     * {@code x = [1, 2, 3, 4]}, {@code y = [1, 2, 3, 4]}, <br>and {@code z(x, y) = x<sup>2</sup> * y<sup>2</sup>}. <br>
-     *          This means that the first row of {@code z} will be all the values obtained by fixing {@code x = 1} and
-     *          iterating over all the values of {@code y}. <br>
-     *          {@code z[0] = [z(1, 1), z(1, 2), z(1, 3), z(1, 4)}; <br>
-     *          Similarly: <br>
-     *          {@code z[1] = [z(2, 1), z(2, 2), z(2, 3), z(2, 4)}; <br>
-     *          and so on. <br>
-     *          Even though internally we iterate over {@code x} and {@code y} multiple times, only a single copy of
-     *          each {@code (x, y)} is required while. Please refer to the example in {@link Spline2DExample}.
-     *
-     * @return A bilinear spline.
-     */
-    public static Spline2D newBilinearSpline(double[] x, double[] y, double[][] z) {
-        final int rows = y.length;
-        final int cols = x.length;
-        final int order = 2;
-
-        if (z.length != y.length) {
-            throw new IllegalArgumentException("The length of z has to be the same length as y.");
-        }
-
-        double[] yt = Arrays.copyOf(y, rows);
-        Spline[] splines = new Spline[rows];
-        for (int i = 0; i < rows; ++i) {
-            if (cols != z[i].length) {
-                throw new IllegalArgumentException("The length of each array in z has to be the same.");
-            }
-            splines[i] = LinearSpline.newLinearSplineInPlace(x, z[i]);
-        }
-        return new Spline2D(yt, splines, order);
-    }
-
     /**
      * Evaluate the spline.
      *

src/main/java/com/wildbitsfoundry/etk4j/math/linearalgebra/ComplexQRDecompositionDense.java

@@ -56,6 +56,15 @@ public static void main(String[] args) {
                 .solve(new ComplexMatrixDense(new Complex[][]{g, f}));
         System.out.println("Solution to system");
         System.out.println(sol);
+
+        ComplexMatrixDense AA = new ComplexMatrixDense(new Complex[][] {
+                {new Complex(1, 1), new Complex(2, 0)},
+                {new Complex(2, -1), new Complex(3, 0)}
+        });
+
+        ComplexQRDecompositionDense qrDecompositionDense = new ComplexQRDecompositionDense(AA);
+        System.out.println(qrDecompositionDense.getQ());
+        System.out.println(qrDecompositionDense.getR());
     }
 
     private static Complex sig(Complex u) {

src/main/java/examples/Spline2DExample.java

@@ -1,9 +1,8 @@
 package examples;
 
-import static com.wildbitsfoundry.etk4j.math.interpolation.Spline2D.newBicubicSpline;
-import static com.wildbitsfoundry.etk4j.math.interpolation.Spline2D.newBilinearSpline;
-
 import com.wildbitsfoundry.etk4j.math.functions.BivariateFunction;
+import com.wildbitsfoundry.etk4j.math.interpolation.BiCubicSpline;
+import com.wildbitsfoundry.etk4j.math.interpolation.BiLinearSpline;
 import com.wildbitsfoundry.etk4j.math.interpolation.Spline2D;
 
 public class Spline2DExample {
@@ -24,11 +23,11 @@ public static void createSurface() {
 		System.out.printf(":: Function z(x, y) = x^2 * y^2%n%n");
 
 		System.out.println(":: Test Bicubic spline");
-		Spline2D sp = newBicubicSpline(x, y, z);
+		Spline2D sp = BiCubicSpline.newBicubicSpline(x, y, z);
 		printSpline2D(sp, x, y);
 
 		System.out.printf("%n:: Test Bilinear spline%n");
-		sp = newBilinearSpline(x, y, z);
+		sp = BiLinearSpline.newBilinearSpline(x, y, z);
 		printSpline2D(sp, x, y);
 	}
 

src/main/java/examples/Spline2DifferentDimensionsExample.java

@@ -1,7 +1,6 @@
 package examples;
 
-import static com.wildbitsfoundry.etk4j.math.interpolation.Spline2D.newBilinearSpline;
-
+import com.wildbitsfoundry.etk4j.math.interpolation.BiLinearSpline;
 import com.wildbitsfoundry.etk4j.math.interpolation.Spline2D;
 
 public class Spline2DifferentDimensionsExample {
@@ -17,7 +16,7 @@ public static void createPlane() {
 		double[][] z = { { 1, 2, 3, 4, 5, 6, 7, 8 }, { 2, 4, 6, 8, 10, 12, 14, 16 }, {3, 6, 9, 12, 15, 18, 21, 24} };
 
 		System.out.printf("%n:: Test Bilinear spline%n");
-		Spline2D sp = newBilinearSpline(x, y, z);
+		Spline2D sp = BiLinearSpline.newBilinearSpline(x, y, z);
 		Spline2DExample.printSpline2D(sp, x, y);
 	}
 }

src/test/java/com/wildbitsfoundry/etk4j/math/interpolation/BicubicSplineTest.java

@@ -1,9 +1,7 @@
 package com.wildbitsfoundry.etk4j.math.interpolation;
 
-import static com.wildbitsfoundry.etk4j.math.interpolation.Spline2D.newBicubicSpline;
 import static org.junit.Assert.assertEquals;
 
-import com.wildbitsfoundry.etk4j.math.interpolation.Spline2D;
 import org.junit.BeforeClass;
 import org.junit.Rule;
 import org.junit.Test;
@@ -33,7 +31,7 @@ public static void setArrays() {
 
 	@Test
 	public void testBicubicInterpolation() {
-		Spline2D sp = newBicubicSpline(x, y, z);
+		Spline2D sp = BiCubicSpline.newBicubicSpline(x, y, z);
 
 		double yi = sp.evaluateAt(xiyi[0][0], xiyi[0][1]);
 		assertEquals(5.0625, yi, 1e-12);

src/test/java/com/wildbitsfoundry/etk4j/math/interpolation/BilinearSplineTest.java

@@ -1,14 +1,12 @@
 package com.wildbitsfoundry.etk4j.math.interpolation;
 
-import static com.wildbitsfoundry.etk4j.math.interpolation.Spline2D.newBilinearSpline;
-import static org.junit.Assert.assertEquals;
-
-import com.wildbitsfoundry.etk4j.math.interpolation.Spline2D;
 import org.junit.BeforeClass;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
+import static org.junit.Assert.assertEquals;
+
 public class BilinearSplineTest {
 	static double[] x;
 	static double[] y;
@@ -33,7 +31,7 @@ public static void setArrays() {
 
 	@Test
 	public void testBilinearSplineInterpolation() {
-		Spline2D sp = newBilinearSpline(x, y, z);
+		Spline2D sp = BiLinearSpline.newBilinearSpline(x, y, z);
 
 		double yi = sp.evaluateAt(xiyi[0][0], xiyi[0][1]);
 		assertEquals(6.2500, yi, 1e-12);