// Create a 3x3 matrix double[,] matrix = new double[3, 3];
// Add elements to the matrix matrix[0, 0] = 1; matrix[0, 1] = 2; matrix[0, 2] = 3; matrix[1, 0] = 4; matrix[1, 1] = 5; matrix[1, 2] = 6; matrix[2, 0] = 7; matrix[2, 1] = 8; matrix[2, 2] = 9;
// Multiply two matrices double[,] matrix1 = new double[,] { { 1, 2 }, { 3, 4 } }; double[,] matrix2 = new double[,] { { 5, 6 }, { 7, 8 } }; double[,] result = new double[2, 2]; for (int i = 0; i < 2; i++) { for (int j = 0; j < 2; j++) { for (int k = 0; k < 2; k++) { result[i, j] += matrix1[i, k] * matrix2[k, j]; } } }Package library: System.Numerics.Matrix.