/**
 * Copyright (C) 2009 - present by OpenGamma Inc. and the OpenGamma group of companies
 *
 * Please see distribution for license.
 */
package com.opengamma.strata.math.impl.linearalgebra;

import static org.testng.AssertJUnit.assertTrue;

import org.apache.commons.math3.linear.Array2DRowRealMatrix;
import org.apache.commons.math3.linear.QRDecomposition;
import org.apache.commons.math3.linear.RealMatrix;
import org.testng.annotations.Test;

import com.opengamma.strata.collect.array.DoubleArray;
import com.opengamma.strata.collect.array.DoubleMatrix;
import com.opengamma.strata.math.impl.FuzzyEquals;

/**
 * Tests the QR decomposition result
 */
@Test
public class QRDecompositionCommonsResultTest {
  static double[][] rawAok = new double[][] { {100.0000000000000000, 9.0000000000000000, 10.0000000000000000, 1.0000000000000000 },
    {9.0000000000000000, 50.0000000000000000, 19.0000000000000000, 15.0000000000000000 }, {10.0000000000000000, 11.0000000000000000, 29.0000000000000000, 21.0000000000000000 },
    {8.0000000000000000, 10.0000000000000000, 20.0000000000000000, 28.0000000000000000 } };
  static double[] rawRHSvect = new double[] {1, 2, 3, 4 };
  static double[][] rawRHSmat = new double[][] { {1, 2 }, {3, 4 }, {5, 6 }, {7, 8 } };

  RealMatrix condok = new Array2DRowRealMatrix(rawAok);
  QRDecomposition qr = new QRDecomposition(condok);
  QRDecompositionCommonsResult result = new QRDecompositionCommonsResult(qr);

  @Test(expectedExceptions = IllegalArgumentException.class)
  public void testThrowOnNull() {
    new QRDecompositionCommonsResult(null);
  }

  public void testGetQ() {
    double[][] expectedRaw = new double[][] { {-0.9879705944808324, 0.1189683945357854, 0.0984381737009301, 0.0083994941034602 },
      {-0.0889173535032749, -0.9595057553635415, 0.2632608647546777, 0.0462182513606091 }, {-0.0987970594480833, -0.1873133740004731, -0.8116464267094188, 0.5444106161481449 },
      {-0.0790376475584666, -0.1735192394127411, -0.5120876107238650, -0.8375024792591188 } };
    assertTrue(FuzzyEquals.ArrayFuzzyEquals(result.getQ().toArray(), expectedRaw));
  }

  public void testGetR() {
    double[][] expectedRaw = new double[][] { {-101.2175874045612574, -15.2147471550048152, -16.0150033365342956, -6.6095232770767698 },
      {0.0000000000000000, -50.7002117254876197, -25.9433980408179785, -23.0657374934840220 }, {0.0000000000000000, 0.0000000000000000, -27.7931604217022681, -27.3356769161449193 },
      {0.0000000000000000, 0.0000000000000000, 0.0000000000000000, -11.3157732156316868 } };
    assertTrue(FuzzyEquals.ArrayFuzzyEquals(result.getR().toArray(), expectedRaw));
  }

  public void testGetQT() {
    double[][] expectedRaw = new double[][] { {-0.9879705944808324, -0.0889173535032749, -0.0987970594480833, -0.0790376475584666 },
      {0.1189683945357854, -0.9595057553635415, -0.1873133740004731, -0.1735192394127411 }, {0.0984381737009301, 0.2632608647546777, -0.8116464267094188, -0.5120876107238650 },
      {0.0083994941034602, 0.0462182513606091, 0.5444106161481449, -0.8375024792591188 } };
    assertTrue(FuzzyEquals.ArrayFuzzyEquals(result.getQT().toArray(), expectedRaw));
  }

  public void testSolveForVector() {
    double[] expectedRaw = new double[] {0.0090821107573878, -0.0038563963265099, -0.0016307897061976, 0.1428043882617839 };
    assertTrue(FuzzyEquals.ArrayFuzzyEquals(result.solve(rawRHSvect), expectedRaw));

    assertTrue(FuzzyEquals.ArrayFuzzyEquals(result.solve(DoubleArray.copyOf(rawRHSvect)).toArray(), expectedRaw));
  }

  public void testSolveForMatrix() {
    double[][] expectedRaw = new double[][] { {0.0103938059732010, 0.0181642215147756 }, {-0.0147149030138629, -0.0077127926530197 }, {-0.0171480759531631, -0.0032615794123952 },
      {0.2645342893362958, 0.2856087765235678 } };

    assertTrue(FuzzyEquals.ArrayFuzzyEquals(result.solve(DoubleMatrix.copyOf(rawRHSmat)).toArray(), expectedRaw));
  }
}