package de.lmu.ifi.dbs.elki.math;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2012
Ludwig-Maximilians-Universität München
Lehr- und Forschungseinheit für Datenbanksysteme
ELKI Development Team
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import java.util.Random;
import org.junit.Test;
import de.lmu.ifi.dbs.elki.JUnit4Test;
import de.lmu.ifi.dbs.elki.math.linearalgebra.Matrix;
public class TestMatrix implements JUnit4Test {
@Test
public void testTransposedOperations() {
for(int i = 0; i < 100; i++) {
randomizedTransposedTest();
randomizedTestAsymmetric();
}
}
private void randomizedTransposedTest() {
Random r = new Random();
int dim = r.nextInt(30) + 10;
Matrix A = new Matrix(dim, dim);
Matrix B = new Matrix(dim, dim);
for(int i = 0; i < dim; i++) {
for(int j = 0; j < dim; j++) {
A.set(i, j, (r.nextDouble() - .5) * 10);
B.set(i, j, (r.nextDouble() - .5) * 10);
}
}
Matrix AT_B = A.transpose().times(B);
org.junit.Assert.assertTrue("A.transposeTimes(B) does not equal A.transpose.times(B)", A.transposeTimes(B).almostEquals(AT_B));
Matrix A_BT = A.times(B.transpose());
org.junit.Assert.assertTrue("A.timesTranspose(B) does not equal A.times(B.transpose)", A.timesTranspose(B).almostEquals(A_BT));
org.junit.Assert.assertTrue("Usually (!) AT_B != A_BT!", !AT_B.almostEquals(A_BT));
Matrix AT_BT = A.transpose().times(B.transpose());
org.junit.Assert.assertTrue("A.transposeTimesTranspose(B) does not equal (B.times(A)).transpose", B.times(A).transpose().almostEquals(AT_BT));
org.junit.Assert.assertTrue("A.transposeTimesTranspose(B) does not equal A.transpose.times(B.transpose)", A.transposeTimesTranspose(B).almostEquals(AT_BT));
}
private void randomizedTestAsymmetric() {
Random r = new Random();
int dim1 = r.nextInt(30) + 10;
int dim2 = r.nextInt(30) + 10;
int dim3 = r.nextInt(30) + 10;
Matrix A = new Matrix(dim1, dim2);
Matrix B = new Matrix(dim2, dim3);
for(int i = 0; i < dim1; i++) {
for(int j = 0; j < dim2; j++) {
A.set(i, j, (r.nextDouble() - .5) * 10);
}
}
for(int i = 0; i < dim2; i++) {
for(int j = 0; j < dim3; j++) {
B.set(i, j, (r.nextDouble() - .5) * 10);
}
}
Matrix A_B = A.times(B);
Matrix BT_AT = B.transpose().times(A.transpose());
Matrix BT_AT2 = B.transposeTimesTranspose(A);
org.junit.Assert.assertTrue("B.transposeTimesTranspose(A) does not equal (A.times(B)).transpose", A_B.transpose().almostEquals(BT_AT));
org.junit.Assert.assertTrue("B.transposeTimesTranspose(A) does not equal B.transpose.times(A.transpose)", BT_AT2.almostEquals(BT_AT));
}
}