public static void test_col()
{
Console.WriteLine("\nTesting col(col_num) ...\n");
Console.WriteLine("\tExpecting (print col 0 of matrix):\t[[1], [3]]");
data = new List<double[]>() { new double[] { 1, 4, 7 }, new double[] { 3, 11, 19 } };
m_from_list = Matrix.from_list(data);
Console.WriteLine("\t Result (print col 0 of matrix):\t" + m_from_list.col(0));
Console.WriteLine("\n\tExpecting (print col 1 of matrix):\t[[4], [11]]");
Console.WriteLine("\t Result (print col 1 of matrix):\t" + m_from_list.col(1));
}