/*******************************************************************************
 * Copyright (c) 2010 Haifeng Li
 *   
 * Licensed 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 smile.projection;

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

import static org.junit.Assert.*;
import smile.math.Math;
import smile.math.matrix.DenseMatrix;
import smile.math.matrix.Matrix;

/**
 *
 * @author Haifeng Li
 */
@SuppressWarnings("unused")
public class GHATest {

    double[][] USArrests = {
        // Murder Assault UrbanPop Rape
        {13.2, 236, 58, 21.2}, // Alabama
        {10.0, 263, 48, 44.5}, // Alaska
        {8.1, 294, 80, 31.0}, // Arizona
        {8.8, 190, 50, 19.5}, // Arkansas
        {9.0, 276, 91, 40.6}, // California
        {7.9, 204, 78, 38.7}, // Colorado
        {3.3, 110, 77, 11.1}, // Connecticut
        {5.9, 238, 72, 15.8}, // Delaware
        {15.4, 335, 80, 31.9}, // Florida
        {17.4, 211, 60, 25.8}, // Georgia
        {5.3, 46, 83, 20.2}, // Hawaii
        {2.6, 120, 54, 14.2}, // Idaho
        {10.4, 249, 83, 24.0}, // Illinois
        {7.2, 113, 65, 21.0}, // Indiana
        {2.2, 56, 57, 11.3}, // Iowa
        {6.0, 115, 66, 18.0}, // Kansas
        {9.7, 109, 52, 16.3}, // Kentucky
        {15.4, 249, 66, 22.2}, // Louisiana
        {2.1, 83, 51, 7.8}, // Maine
        {11.3, 300, 67, 27.8}, // Maryland
        {4.4, 149, 85, 16.3}, // Massachusetts
        {12.1, 255, 74, 35.1}, // Michigan
        {2.7, 72, 66, 14.9}, // Michigan
        {16.1, 259, 44, 17.1}, // Mississippi
        {9.0, 178, 70, 28.2}, // Missouri
        {6.0, 109, 53, 16.4}, // Montana
        {4.3, 102, 62, 16.5}, // Nebraska
        {12.2, 252, 81, 46.0}, // Nevada
        {2.1, 57, 56, 9.5}, // New Hampshire
        {7.4, 159, 89, 18.8}, // New Jersey
        {11.4, 285, 70, 32.1}, // New Mexico
        {11.1, 254, 86, 26.1}, // New York
        {13.0, 337, 45, 16.1}, // North Carolina
        {0.8, 45, 44, 7.3}, // North Dakota
        {7.3, 120, 75, 21.4}, // Ohio
        {6.6, 151, 68, 20.0}, // Oklahoma
        {4.9, 159, 67, 29.3}, // Oregon
        {6.3, 106, 72, 14.9}, // Pennsylvania
        {3.4, 174, 87, 8.3}, // Rhode Island
        {14.4, 279, 48, 22.5}, // South Carolina
        {3.8, 86, 45, 12.8}, // South Dakota
        {13.2, 188, 59, 26.9}, // Tennessee
        {12.7, 201, 80, 25.5}, // Texas
        {3.2, 120, 80, 22.9}, // Utah
        {2.2, 48, 32, 11.2}, // Vermont
        {8.5, 156, 63, 20.7}, // Virginia
        {4.0, 145, 73, 26.2}, // Washington
        {5.7, 81, 39, 9.3}, // West Virginia
        {2.6, 53, 66, 10.8}, // Wisconsin
        {6.8, 161, 60, 15.6} // Wyoming
    };
    double[][] loadings = {
        {-0.0417043206282872, -0.0448216562696701, -0.0798906594208108, -0.994921731246978},
        {-0.995221281426497, -0.058760027857223, 0.0675697350838043, 0.0389382976351601},
        {-0.0463357461197108, 0.97685747990989, 0.200546287353866, -0.0581691430589319},
        {-0.075155500585547, 0.200718066450337, -0.974080592182491, 0.0723250196376097}
    };
    double[] eigenvalues = {7011.114851, 201.992366, 42.112651, 6.164246};

    public GHATest() {
    }

    @BeforeClass
    public static void setUpClass() throws Exception {
    }

    @AfterClass
    public static void tearDownClass() throws Exception {
    }

    @Before
    public void setUp() {
    }

    @After
    public void tearDown() {
    }

    /**
     * Test of learn method, of class GHA.
     */
    @Test
    public void testLearn() {
        System.out.println("learn");

        int k = 3;
        double[] mu = Math.colMeans(USArrests);
        DenseMatrix cov = Matrix.newInstance(Math.cov(USArrests));
        for (int i = 0; i < USArrests.length; i++) {
           Math.minus(USArrests[i], mu);
        }

        double r = 0.00001;
        GHA gha = new GHA(4, k, r);
        for (int iter = 1, t = 0; iter <= 1000; iter++) {
            double error = 0.0;
            for (int i = 0; i < USArrests.length; i++, t++) {
                error += gha.learn(USArrests[i]);
            }
            error /= USArrests.length;

            if (iter % 100 == 0) {
                System.out.format("Iter %3d, Error = %.5g%n", iter, error);
            }
        }

        DenseMatrix p = gha.getProjection();
        DenseMatrix t = p.ata();

        for (int i = 0; i < t.nrows(); i++) {
            for (int j = 0; j < t.ncols(); j++) {
                System.out.format("% .4f ", t.get(i, j));
            }
            System.out.println();
        }

        DenseMatrix s = p.abmm(cov).abtmm(p);
        double[] ev = new double[k];
        System.out.println("Relative error of eigenvalues:");
        for (int i = 0; i < k; i++) {
            ev[i] = Math.abs(eigenvalues[i] - s.get(i, i)) / eigenvalues[i];
            System.out.format("%.4f ", ev[i]);
        }
        System.out.println();

        for (int i = 0; i < k; i++) {
            assertTrue(ev[i] < 0.1);
        }

        double[][] lt = Math.transpose(loadings);
        double[] evdot = new double[k];
        double[][] pa = p.array();
        System.out.println("Dot products of learned eigenvectors to true eigenvectors:");
        for (int i = 0; i < k; i++) {
            evdot[i] = Math.dot(lt[i], pa[i]);
            System.out.format("%.4f ", evdot[i]);
        }
        System.out.println();

        for (int i = 0; i < k; i++) {
            assertTrue(Math.abs(1.0-Math.abs(evdot[i])) < 0.1);
        }
    }
}