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* 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.
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package org.apache.mahout.math.als;
import java.util.Arrays;
import org.apache.mahout.math.DenseMatrix;
import org.apache.mahout.math.DenseVector;
import org.apache.mahout.math.MahoutTestCase;
import org.apache.mahout.math.Matrix;
import org.apache.mahout.math.RandomAccessSparseVector;
import org.apache.mahout.math.SequentialAccessSparseVector;
import org.apache.mahout.math.SparseMatrix;
import org.apache.mahout.math.Vector;
import org.apache.mahout.math.map.OpenIntObjectHashMap;
import org.junit.Test;
public class AlternatingLeastSquaresSolverTest extends MahoutTestCase {
@Test
public void testYtY() {
double[][] testMatrix = new double[][] {
new double[] { 1, 2, 3, 4, 5 },
new double[] { 1, 2, 3, 4, 5 },
new double[] { 1, 2, 3, 4, 5 },
new double[] { 1, 2, 3, 4, 5 },
new double[] { 1, 2, 3, 4, 5 }};
double[][] testMatrix2 = new double[][] {
new double[] { 1, 2, 3, 4, 5, 6 },
new double[] { 5, 4, 3, 2, 1, 7 },
new double[] { 1, 2, 3, 4, 5, 8 },
new double[] { 1, 2, 3, 4, 5, 8 },
new double[] { 11, 12, 13, 20, 27, 8 }};
double[][][] testData = new double[][][] {
testMatrix,
testMatrix2 };
for (int i = 0; i < testData.length; i++) {
Matrix matrixToTest = new DenseMatrix(testData[i]);
//test for race conditions by trying a few times
for (int j = 0; j < 100; j++) {
validateYtY(matrixToTest, 4);
}
//one thread @ a time test
validateYtY(matrixToTest, 1);
}
}
private void validateYtY(Matrix matrixToTest, int numThreads) {
OpenIntObjectHashMap<Vector> matrixToTestAsRowVectors = asRowVectors(matrixToTest);
ImplicitFeedbackAlternatingLeastSquaresSolver solver = new ImplicitFeedbackAlternatingLeastSquaresSolver(
matrixToTest.columnSize(), 1, 1, matrixToTestAsRowVectors, numThreads);
Matrix yTy = matrixToTest.transpose().times(matrixToTest);
Matrix shouldMatchyTy = solver.getYtransposeY(matrixToTestAsRowVectors);
for (int row = 0; row < yTy.rowSize(); row++) {
for (int column = 0; column < yTy.columnSize(); column++) {
assertEquals(yTy.getQuick(row, column), shouldMatchyTy.getQuick(row, column), 0);
}
}
}
private OpenIntObjectHashMap<Vector> asRowVectors(Matrix matrix) {
OpenIntObjectHashMap<Vector> rows = new OpenIntObjectHashMap<Vector>();
for (int row = 0; row < matrix.numRows(); row++) {
rows.put(row, matrix.viewRow(row).clone());
}
return rows;
}
@Test
public void addLambdaTimesNuiTimesE() {
int nui = 5;
double lambda = 0.2;
Matrix matrix = new SparseMatrix(5, 5);
AlternatingLeastSquaresSolver.addLambdaTimesNuiTimesE(matrix, lambda, nui);
for (int n = 0; n < 5; n++) {
assertEquals(1.0, matrix.getQuick(n, n), EPSILON);
}
}
@Test
public void createMiIi() {
Vector f1 = new DenseVector(new double[] { 1, 2, 3 });
Vector f2 = new DenseVector(new double[] { 4, 5, 6 });
Matrix miIi = AlternatingLeastSquaresSolver.createMiIi(Arrays.asList(f1, f2), 3);
assertEquals(1.0, miIi.getQuick(0, 0), EPSILON);
assertEquals(2.0, miIi.getQuick(1, 0), EPSILON);
assertEquals(3.0, miIi.getQuick(2, 0), EPSILON);
assertEquals(4.0, miIi.getQuick(0, 1), EPSILON);
assertEquals(5.0, miIi.getQuick(1, 1), EPSILON);
assertEquals(6.0, miIi.getQuick(2, 1), EPSILON);
}
@Test
public void createRiIiMaybeTransposed() {
Vector ratings = new SequentialAccessSparseVector(3);
ratings.setQuick(1, 1.0);
ratings.setQuick(3, 3.0);
ratings.setQuick(5, 5.0);
Matrix riIiMaybeTransposed = AlternatingLeastSquaresSolver.createRiIiMaybeTransposed(ratings);
assertEquals(1, riIiMaybeTransposed.numCols(), 1);
assertEquals(3, riIiMaybeTransposed.numRows(), 3);
assertEquals(1.0, riIiMaybeTransposed.getQuick(0, 0), EPSILON);
assertEquals(3.0, riIiMaybeTransposed.getQuick(1, 0), EPSILON);
assertEquals(5.0, riIiMaybeTransposed.getQuick(2, 0), EPSILON);
}
@Test
public void createRiIiMaybeTransposedExceptionOnNonSequentialVector() {
Vector ratings = new RandomAccessSparseVector(3);
ratings.setQuick(1, 1.0);
ratings.setQuick(3, 3.0);
ratings.setQuick(5, 5.0);
try {
AlternatingLeastSquaresSolver.createRiIiMaybeTransposed(ratings);
fail();
} catch (IllegalArgumentException e) {}
}
}