com.analog.lyric.math.MoreMatrixUtils.java Source code

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/*******************************************************************************
*   Copyright 2015 Analog Devices, Inc.
*
*   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 com.analog.lyric.math;

import org.apache.commons.math3.linear.Array2DRowRealMatrix;
import org.apache.commons.math3.linear.ArrayRealVector;
import org.apache.commons.math3.linear.RealMatrix;
import org.apache.commons.math3.linear.RealVector;

/**
 * More Apache Matrix utilities ala {@linkplain org.apache.commons.math3.linear.MatrixUtils MatrixUtils}.
 * <p>
 * @since 0.08
 * @author Christopher Barber
 */
public class MoreMatrixUtils {
    /**
     * Returns matrix as 2D row-major array.
     * <p>
     * If {@code matrix} is a {@link Array2DRowRealMatrix}, this returns its underlying array,
     * otherwise returns a newly allocated array.
     * <p>
     * @since 0.08
     */
    public static double[][] matrixGetDataRef(RealMatrix matrix) {
        if (matrix instanceof Array2DRowRealMatrix) {
            return ((Array2DRowRealMatrix) matrix).getDataRef();
        }

        return matrix.getData();
    }

    /**
     * Returns vector as a an array.
     * <p>
     * If {@code vector} is a {@link ArrayRealVector}, this returns its underlying array,
     * otherwise returns a newly allocated array.
     * @since 0.08
     */
    public static double[] vectorGetDataRef(RealVector vector) {
        if (vector instanceof ArrayRealVector) {
            return ((ArrayRealVector) vector).getDataRef();
        }

        return vector.toArray();
    }

    /**
     * Return row-real matrix that uses specified underlying representation.
     * <p>
     * Simply shorthand for invoking {@link Array2DRowRealMatrix#Array2DRowRealMatrix(double[][], boolean)}
     * constructor with {@code copyArray} argument set to false.
     * @since 0.08
     */
    public static Array2DRowRealMatrix wrapRealMatrix(double[][] data) {
        return new Array2DRowRealMatrix(data, false);
    }

    /**
     * Return real vector that uses specified underlying representation.
     * <p>
     * Simply shorthand for invoking {@link ArrayRealVector#ArrayRealVector(double[], boolean)}
     * constructor with {@code copyArray} argument set to false.
     * @since 0.08
     */
    public static ArrayRealVector wrapRealVector(double[] data) {
        return new ArrayRealVector(data, false);
    }

}