using System;

using MathNet.Numerics.LinearAlgebra;

​

public static class Program {

    public static void Main() {

        // Sample input

        var input = 

          @"1, 2, 3

            4, 5, 6

            7, 8, 9";

        var res = ParseMatrix(input);

        Console.WriteLine(res);

    }

    public static Matrix<double> ParseMatrix(string input) {

        // Get lines

        var lines = input.Split(Environment.NewLine);

        // Initialize the result variable

        var result = new double[lines.Length][];

        // Loop over the lines

        for (var i = 0; i < lines.Length; i++)

        {

            // Split the line into its elements

            var els = lines[i].Split(',');

            // Initialize a blank row

            var row = new double[els.Length];

            // Loop over the elements

            for (var ii = 0; ii < els.Length; ii++)

            {

                // Parse the element to a double and insert it into a row

                row[ii] = double.Parse(els[ii]);    

            }

            // Insert the row into the final result

            result[i] = row;

        }

        // Print out the result

        foreach (var l in result)

        {

            Console.WriteLine(string.Join(", ", l));

        }

        Matrix<double> matrix = Matrix<double>.Build.DenseOfColumns(result);

        return matrix;

    }

}