How to Use a Matrix in Vb.Net

It is relatively easy to work with matrices in VB.NET.

A matrix is a grid and each location in this grid contains a piece of information. Take a chessboard for example: It is a matrix and each square is one of its elements. Matrices are useful in real life to represent large amounts of data. The data can be processed more conveniently because it is represented in a concise manner. Using a matrix in VB.NET is just like using it in math. However, you must know how to write code to work with matrices.

Instructions

1. Open VB.NET and create a TWO-dimensional array. You must first declare a class for your new matrix. You use the "M" variable for the number of columns and the "N" variable for the number of rows. Here is the code to generate this class in VB.NET:

   Public Class Matrix
   Implements ICloneable
   Private M As Integer
   Private N As Integer
   Public val(,) As Double
   Private currentX As Integer
   Private currentY As Integer
   End Class

   Note that the number of columns and the number of rows are integers. "val(,)" is an array with two dimensions that contains the elements of your matrix.

2. Assign proper dimensions to your matrix in the class constructor by using this code:

   Public Sub New(ByVal X As Integer, ByVal Y As Integer)
   SetDimensions(X, Y)
   currentX = 0
   currentY = 0
   End Sub

   Here is how you create a square matrix:

   Public Sub New(ByVal X As Integer)
   SetDimensions(X, X)
   currentX = 0
   currentY = 0
   End Sub

3. Add one matrix to another by using a function that takes a matrix as a parameter and does element-by-element addition. The result will be a matrix. Use this code for your function:

   Public Function Add(ByVal C As Matrix) As Matrix
   If M <> C.M Or N <> C.N Then
   Throw New Exception("Matrices size Mismatch.")
   End If
   Dim B As Matrix = New Matrix(M, N)
   For i As Integer = 0 To M - 1
   For j As Integer = 0 To N - 1
   B.val(i, j) = val(i, j) + C.val(i, j)
   Next
   Next
   Return B
   End Function

4. Multiply one matrix by another by using a function that returns a matrix. Note that you can only multiply two matrices only if the number of columns of the first is equal to the number of rows of the second. This function multiplies matrix "X" with matrix "Y," and returns the new matrix:

   public class Test
   public Shared Sub Main
   Dim X As New Matrix(2.0F, 1.0F, 3.0F, 1.0F, 0.0F, 4.0F)
   Dim Y As New Matrix(0.0F, 1.0F, -1.0F, 0.0F, 0.0F, 0.0F)
   X.Multiply(Y, MatrixOrder.Append)
   Dim i As Integer
   For i = 0 To X.Elements.Length - 1
   Console.WriteLine(X.Elements(i).ToString())
   Next i
   End Sub
   End class

   Note that this function also reads the resulting matrix.

5. Raise a matrix to power by multiplying it with itself.

References

• Microsoft: Matrix.Multiply Method
• CodeProject: A Matrix Class Explained with Mathematical Equations

Resources

• Cycling74.com: What is a Matrix?
• Microsoft: Arrays in Visual Basic