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 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
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package org.ojalgo.matrix;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.ojalgo.TestUtils;
import org.ojalgo.matrix.decomposition.Cholesky;
import org.ojalgo.matrix.store.GenericStore;
import org.ojalgo.matrix.store.RawStore;
import org.ojalgo.scalar.RationalNumber;
import org.ojalgo.type.context.NumberContext;

/**
 * This problem is taken from example 2.21 of the Scientific Computing, An Introductory Survey.
 *
 * @author apete
 */
public class SimpleCholeskyCase extends BasicMatrixTest {

    private static final NumberContext DEFINITION = NumberContext.of(7, 4);

    /**
     * This matrix is taken from example 2.21 of the Scientific Computing, An Introductory Survey
     *
     * @return The data00 value
     */
    public static MatrixR064 getOriginal() {
        return MatrixR064.FACTORY.copy(RawStore.wrap(new double[][] { { 3.0, -1.0, -1.0 }, { -1.0, 3.0, -1.0 }, { -1.0, -1.0, 3.0 } })).enforce(DEFINITION);
    }

    private static MatrixR064 getFactorL() {
        return MatrixR064.FACTORY.copy(RawStore.wrap(new double[][] { { 1.7321, 0.0, 0.0 }, { -0.5774, 1.6330, 0.0 }, { -0.5774, -0.8165, 1.4142 } }))
                .enforce(DEFINITION);
    }

    private static MatrixR064 getFactorR() {
        return MatrixR064.FACTORY.copy(RawStore.wrap(new double[][] { { 1.7321, -0.5774, -0.5774 }, { 0.0, 1.6330, -0.8165 }, { 0.0, 0.0, 1.4142 } }))
                .enforce(DEFINITION);
    }

    @Override
    @BeforeEach
    public void doBeforeEach() {

        mtrxA = SimpleCholeskyCase.getFactorL();
        mtrxX = SimpleCholeskyCase.getFactorR();
        mtrxB = SimpleCholeskyCase.getOriginal();

        mtrxI = BasicMatrixTest.getIdentity(mtrxA.countRows(), mtrxA.countColumns(), DEFINITION);
        mtrxSafe = BasicMatrixTest.getSafe(mtrxA.countRows(), mtrxA.countColumns(), DEFINITION);

        super.doBeforeEach();
    }

    @Test
    public void testData() {

        NumberContext accuracy = NumberContext.of(4, 3);

        MatrixR064 tmpA = SimpleCholeskyCase.getOriginal();
        MatrixR064 tmpL = SimpleCholeskyCase.getFactorL();
        MatrixR064 tmpR = SimpleCholeskyCase.getFactorR();

        BasicMatrix<?, ?> actMtrx;
        BasicMatrix<?, ?> expMtrx;

        expMtrx = tmpL;
        actMtrx = tmpR.transpose();

        TestUtils.assertEquals(expMtrx, actMtrx, accuracy);

        expMtrx = tmpA;
        actMtrx = tmpL.multiply(tmpR);

        TestUtils.assertEquals(expMtrx, actMtrx, accuracy);
    }

    @Test
    public void testProblem() {

        MatrixR064 tmpMtrx = SimpleCholeskyCase.getOriginal();
        Cholesky<RationalNumber> tmpDecomp = Cholesky.Q128.make();
        tmpDecomp.decompose(GenericStore.Q128.copy(tmpMtrx));

        TestUtils.assertEquals(GenericStore.Q128.copy(tmpMtrx), tmpDecomp, ACCURACY);
    }

}
