praktikum-holons/src/holeg/power_flow/Util.java

package holeg.power_flow;

import Jama.Matrix;

import java.util.ArrayList;

public class Util {
    public static double[] subtract(double[] a, double[] b) {
        if (a == null)
            throw new IllegalArgumentException("a is null");
        if (b == null)
            throw new IllegalArgumentException("b is null");
        if (a.length != b.length)
            throw new IllegalArgumentException("a size does not match b size");
        double[] r = new double[a.length];
        for (int i = 0; i < r.length; i++)
            r[i] = a[i] - b[i];
        return r;
    }

    public static int[] indicesOf(Bus[] array, BusType value) {
        if (array == null)
            throw new IllegalArgumentException("array is null");
        if (array.length == 0)
            return new int[0];

        ArrayList<Integer> indices = new ArrayList<Integer>(array.length);
        for (int i = 0; i < array.length; i++)
            if (array[i].type.equals(value))
                indices.add(i);
        return indices.stream().mapToInt(i -> i).toArray();
    }

    public static Matrix fromArray(double[] array) {
        if (array == null)
            throw new IllegalArgumentException("array is null");
        Matrix m = new Matrix(array.length, 1);
        for (int i = 0; i < array.length; i++)
            m.set(i, 0, array[i]);
        return m;
    }

    public static Matrix concatColumns(Matrix a, Matrix b) {
        if (a == null)
            throw new IllegalArgumentException("a is null");
        if (b == null)
            throw new IllegalArgumentException("b is null");
        if (a.getRowDimension() != b.getRowDimension())
            throw new IllegalArgumentException("rows count do not match");

        Matrix c = new Matrix(a.getRowDimension(), a.getColumnDimension() + b.getColumnDimension());
        for (int i = 0; i < a.getRowDimension(); i++)
            for (int j = 0; j < a.getColumnDimension(); j++)
                c.set(i, j, a.get(i, j));
        for (int i = 0; i < b.getRowDimension(); i++)
            for (int j = 0; j < b.getColumnDimension(); j++)
                c.set(i, j + a.getColumnDimension(), b.get(i, j));
        return c;
    }

    public static Matrix concatRows(Matrix a, Matrix b) {
        if (a == null)
            throw new IllegalArgumentException("a is null");
        if (b == null)
            throw new IllegalArgumentException("b is null");
        if (a.getColumnDimension() != b.getColumnDimension())
            throw new IllegalArgumentException("columns count do not match");

        Matrix c = new Matrix(a.getRowDimension() + b.getRowDimension(), a.getColumnDimension());
        for (int i = 0; i < a.getRowDimension(); i++)
            for (int j = 0; j < a.getColumnDimension(); j++)
                c.set(i, j, a.get(i, j));
        for (int i = 0; i < b.getRowDimension(); i++)
            for (int j = 0; j < b.getColumnDimension(); j++)
                c.set(i + a.getRowDimension(), j, b.get(i, j));
        return c;
    }
}