Software/Visual_Studio/SideChains/Colourful/Implementation/Utils/MatrixFactory.cs


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46

using Vector = System.Collections.Generic.IReadOnlyList<double>;
using Matrix = System.Collections.Generic.IReadOnlyList<System.Collections.Generic.IReadOnlyList<double>>;

namespace Colourful.Implementation
{
    internal static class MatrixFactory
    {
        public static double[][] CreateEmpty(int rows, int columns)
        {
            var result = new double[rows][];
            for (var i = 0; i < rows; i++)
            {
                result[i] = new double[columns];
            }

            return result;
        }

        public static Matrix CreateIdentity(int size)
        {
            var result = new double[size][];
            for (var i = 0; i < size; i++)
            {
                result[i] = new double[size];
                result[i][i] = 1;
            }

            // ReSharper disable once CoVariantArrayConversion
            return result;
        }

        public static Matrix CreateDiagonal(params double[] items)
        {
            var size = items.Length;
            var result = new double[size][];
            for (var i = 0; i < size; i++)
            {
                result[i] = new double[size];
                result[i][i] = items[i];
            }

            // ReSharper disable once CoVariantArrayConversion
            return result;
        }
    }
}