VB Matrix Arithmetic Example

Imports System

Imports CenterSpace.NMath.Core

Namespace CenterSpace.NMath.Examples.VisualBasic

  A .NET example in Visual Basic showing the element-wise operators overloaded for
  matrix/matrix and matrix/scalar operations.
  
  The arithmetic operators +,-,*,/ are overloaded
  for matrix-matrix and matrix-scalar operations. These operators
  have their usual meanings. For example, if A, B, and C are
  matrices, s is a scalar and op is one of +,-,*,/, then
  
    C = A op B
    
  produces a matrix C such that
  
    C[i,j] = A[i,j] op B[i,j]
    
  and 
  
    C = s op B
    
  produces a matrix C such that
  
    C[i,j] = s op B[i,j].
  Module MatrixArithmeticExample

    Sub Main()

      Console.WriteLine()

      Dim rows As Integer = 3
      Dim cols As Integer = 3

      Create a matrix containing all (1,0)s
      Dim A As New DoubleComplexMatrix(rows, cols, New DoubleComplex(1, 0))
      Create a matrix containing all (0,1)s
      Dim B As New DoubleComplexMatrix(rows, cols, New DoubleComplex(0, 1))
      Console.WriteLine("A = {0}", A.ToString())
      Console.WriteLine("B = {0}", B.ToString())

      Adding them together will yield a matrix of the same size containing 
      all (1,1)s
      Dim S As DoubleComplexMatrix = A + B
      Console.WriteLine("A + B = {0}", S.ToString())

      Vector scalar operators are also provided.
      Dim c As New DoubleComplex(2, 0)

      Produces a matrix containing all (1,2)s
      Dim aSum As DoubleComplexMatrix = A + (c * B)
      Console.WriteLine("A + c*B = {0}", aSum.ToString())

      If we increase the number of rows of A and try to multiply with B, we
      will get a MismatchedSizeException. Matrices must have the same
      dimensions to be combined using the element-wise operators.
      A.Resize(rows + 1, cols)
      Dim P As DoubleComplexMatrix
      Try
        P = A * B
      Catch e As MismatchedSizeException
        Console.WriteLine("Oops - " + e.Message)
      End Try

      Put A back the way it was.
      A.Resize(rows, cols)

      Increment and decrement operators have been overloaded too
      (for real types only).
      Dim Areal As DoubleMatrix = NMathFunctions.Real(A)
      Console.WriteLine("Areal = {0}", Areal.ToString())
      Areal = DoubleMatrix.Increment(Areal)
      Console.WriteLine("Areal++ = {0}", Areal.ToString())

      Console.WriteLine()
      Console.WriteLine("Press Enter Key")
      Console.Read()

    End Sub

  End Module

End Namespace