Added unit testing of FieldLUDecompositionImpl.Solver. This test is largely based on LUSolverTest, using Fraction instead of double. It resolves issue MATH-673.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1172988 13f79535-47bb-0310-9956-ffa450edef68

src/test/java/org/apache/commons/math/linear/FieldLUSolverTest.java

@@ -0,0 +1,177 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.math.linear;
+
+import org.apache.commons.math.exception.MathIllegalArgumentException;
+import org.apache.commons.math.fraction.Fraction;
+import org.apache.commons.math.fraction.FractionField;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class FieldLUSolverTest {
+    private int[][] testData = {
+            { 1, 2, 3},
+            { 2, 5, 3},
+            { 1, 0, 8}
+    };
+    private int[][] luData = {
+            { 2, 3, 3 },
+            { 0, 5, 7 },
+            { 6, 9, 8 }
+    };
+
+    // singular matrices
+    private int[][] singular = {
+            { 2, 3 },
+            { 2, 3 }
+    };
+    private int[][] bigSingular = {
+            { 1, 2,   3,    4 },
+            { 2, 5,   3,    4 },
+            { 7, 3, 256, 1930 },
+            { 3, 7,   6,    8 }
+    }; // 4th row = 1st + 2nd
+
+    public static FieldMatrix<Fraction> createFractionMatrix(final int[][] data) {
+        final int numRows = data.length;
+        final int numCols = data[0].length;
+        final Array2DRowFieldMatrix<Fraction> m;
+        m = new Array2DRowFieldMatrix<Fraction>(FractionField.getInstance(),
+                                                numRows, numCols);
+        for (int i = 0; i < numRows; i++) {
+            for (int j = 0; j < numCols; j++) {
+                m.setEntry(i, j, new Fraction(data[i][j], 1));
+            }
+        }
+        return m;
+    }
+
+    /** test singular */
+    @Test
+    public void testSingular() {
+        FieldDecompositionSolver<Fraction> solver;
+        solver = new FieldLUDecompositionImpl<Fraction>(createFractionMatrix(testData))
+            .getSolver();
+        Assert.assertTrue(solver.isNonSingular());
+        solver = new FieldLUDecompositionImpl<Fraction>(createFractionMatrix(singular))
+            .getSolver();
+        Assert.assertFalse(solver.isNonSingular());
+        solver = new FieldLUDecompositionImpl<Fraction>(createFractionMatrix(bigSingular))
+            .getSolver();
+        Assert.assertFalse(solver.isNonSingular());
+    }
+
+    /** test solve dimension errors */
+    @Test
+    public void testSolveDimensionErrors() {
+        FieldDecompositionSolver<Fraction> solver;
+        solver = new FieldLUDecompositionImpl<Fraction>(createFractionMatrix(testData))
+            .getSolver();
+        FieldMatrix<Fraction> b = createFractionMatrix(new int[2][2]);
+        try {
+            solver.solve(b);
+            Assert.fail("an exception should have been thrown");
+        } catch (MathIllegalArgumentException iae) {
+            // expected behavior
+        }
+        try {
+            solver.solve(b.getColumnVector(0));
+            Assert.fail("an exception should have been thrown");
+        } catch (MathIllegalArgumentException iae) {
+            // expected behavior
+        }
+    }
+
+    /** test solve singularity errors */
+    @Test
+    public void testSolveSingularityErrors() {
+        FieldDecompositionSolver solver;
+        solver = new FieldLUDecompositionImpl(createFractionMatrix(singular))
+            .getSolver();
+        FieldMatrix b = createFractionMatrix(new int[2][2]);
+        try {
+            solver.solve(b);
+            Assert.fail("an exception should have been thrown");
+        } catch (SingularMatrixException ime) {
+            // expected behavior
+        }
+        try {
+            solver.solve(b.getColumnVector(0));
+            Assert.fail("an exception should have been thrown");
+        } catch (SingularMatrixException ime) {
+            // expected behavior
+        }
+    }
+
+    /** test solve */
+    @Test
+    public void testSolve() {
+        FieldDecompositionSolver solver;
+        solver = new FieldLUDecompositionImpl<Fraction>(createFractionMatrix(testData))
+            .getSolver();
+        FieldMatrix<Fraction> b = createFractionMatrix(new int[][] {
+                { 1, 0 }, { 2, -5 }, { 3, 1 }
+        });
+        FieldMatrix<Fraction> xRef = createFractionMatrix(new int[][] {
+                { 19, -71 }, { -6, 22 }, { -2, 9 }
+        });
+
+        // using FieldMatrix
+        FieldMatrix<Fraction> x = solver.solve(b);
+        for (int i = 0; i < x.getRowDimension(); i++){
+            for (int j = 0; j < x.getColumnDimension(); j++){
+                Assert.assertEquals("(" + i + ", " + j + ")",
+                                    xRef.getEntry(i, j), x.getEntry(i, j));
+            }
+        }
+
+        // using ArrayFieldVector
+        for (int j = 0; j < b.getColumnDimension(); j++) {
+            final FieldVector<Fraction> xj = solver.solve(b.getColumnVector(j));
+            for (int i = 0; i < xj.getDimension(); i++){
+                Assert.assertEquals("(" + i + ", " + j + ")",
+                                    xRef.getEntry(i, j), xj.getEntry(i));
+            }
+        }
+
+        // using SparseFieldVector
+        for (int j = 0; j < b.getColumnDimension(); j++) {
+            final SparseFieldVector<Fraction> bj;
+            bj = new SparseFieldVector<Fraction>(FractionField.getInstance(),
+                                                 b.getColumn(j));
+            final FieldVector<Fraction> xj = solver.solve(bj);
+            for (int i = 0; i < xj.getDimension(); i++) {
+                Assert.assertEquals("(" + i + ", " + j + ")",
+                                    xRef.getEntry(i, j), xj.getEntry(i));
+            }
+        }
+    }
+
+    /** test determinant */
+    @Test
+    public void testDeterminant() {
+        Assert.assertEquals( -1, getDeterminant(createFractionMatrix(testData)), 1E-15);
+        Assert.assertEquals(-10, getDeterminant(createFractionMatrix(luData)), 1E-14);
+        Assert.assertEquals(  0, getDeterminant(createFractionMatrix(singular)), 1E-15);
+        Assert.assertEquals(  0, getDeterminant(createFractionMatrix(bigSingular)), 1E-15);
+    }
+
+    private double getDeterminant(final FieldMatrix<Fraction> m) {
+        return new FieldLUDecompositionImpl<Fraction>(m).getDeterminant().doubleValue();
+    }
+}