How can I convert matrix to Matrix?

Question

I want to calculate something like: Matrix<float> * Matrix<double>

the Matrix<float> has about 6M*3 elements , how can I convert the Matrix<double> to Matrix<float> so that I can get a Matrix<float> result.

How big is "very big", and is created a copy of the original `Matrix` (but using `double` values) prohibitively slow/memory-hungry? (If you haven't at last tried that, that seems like the simplest option...) — Jon Skeet, May 12 '15 at 15:28

Christoph Rüegg · Accepted Answer · 2015-05-12T16:35:04.173

3

You can convert your double matrix argument to a float matrix using the Map function:

Matrix<double> m1 = Matrix<double>.Build.Random(6000000,3);
Matrix<float> m2 = m1.Map(x => (float)x);

Or alternatively

Matrix<float> m2 = m1.Map(Convert.ToSingle);

edited May 12 '15 at 16:35

answered May 12 '15 at 16:28

Christoph Rüegg

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score 1 · Answer 2 · answered May 12 '15 at 15:29

Here's how to convert an array of double to an array of float, then you just need to convert your matrix to array and vice versa

public static float[][] Convert(double[][] mtx)
{
    var floatMtx = new float[mtx.Length][];
    for (int i = 0; i < mtx.Length; i++)
    {
        floatMtx[i] = new float[mtx[i].Length];
        for (int j = 0; j < mtx[i].Length; j++)
            floatMtx[i][j] = (float)mtx[i][j];
    }
    return floatMtx;
}
Or:

public static float[][] Convert(double[][] mtx)
{
    return mtx.Select(i => i.Select(j => (float)j).ToArray()).ToArray();
}

How can I convert matrix to Matrix?

2 Answers2