com.github.thorbenlindhauer.test.util.LinearAlgebraUtil.java Source code

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Here is the source code for com.github.thorbenlindhauer.test.util.LinearAlgebraUtil.java

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/* 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.github.thorbenlindhauer.test.util;

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;

import org.apache.commons.math3.linear.MatrixUtils;

/**
 * @author Thorben
 *
 */
public class LinearAlgebraUtil {

    public static RealVector asVector(double value) {
        return new ArrayRealVector(new double[] { value });
    }

    public static RealMatrix asMatrix(double... values) {
        return new Array2DRowRealMatrix(new double[][] { values });
    }

    public static RealMatrix asSingleRowMatrix(double value, int repetitions) {
        double[] values = new double[repetitions];
        for (int i = 0; i < repetitions; i++) {
            values[i] = value;
        }

        RealMatrix matrix = new Array2DRowRealMatrix(1, repetitions);
        matrix.setRow(0, values);
        return matrix;
    }

    public static RealMatrix asRowMatrix(double... values) {
        RealMatrix matrix = new Array2DRowRealMatrix(1, values.length);
        matrix.setRow(0, values);
        return matrix;
    }

    public static RealMatrix diagonalMatrix(double value, int size) {
        double[] values = new double[size];
        for (int i = 0; i < size; i++) {
            values[i] = value;
        }

        return MatrixUtils.createRealDiagonalMatrix(values);
    }
}