VB Vector 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
  vector/vector and vector/scalar operations.
  
  The arithmetic operators +,-,*,/ are overloaded
  for vector-vector and vector-scalar operations. These operators
  have their usual meanings. For example, if u, v, and w are
  vectors, s is a scalar and op is one of +,-,*,/, then
  
    w = u op v
    
  produces a vector w such that
  
    w[i] = u[i] op v[i]
    
  and 
  
    w = s op v
    
  produces a vector w such that
  
    w[i] = s op v[i].
  Module VectorArithmeticExample

    Sub Main()

      Dim length As Integer = 5

      Console.WriteLine()

      Create two vectors v1 and v2. v1 alternates values 1, 0, 1,...
      and v2 alternates values 0, 1, 0,...
      Dim v1 As New FloatVector(length)
      Dim v2 As New FloatVector(length)
      Dim everyOther As New Range(0, Position.End, 2)
      v1.Set(everyOther, 1)
      everyOther.Set(1, Position.End, 2)
      v2.Set(everyOther, 1)
      Console.WriteLine("v1 = {0}", v1.ToString())   v1 = [1 0 1 0 1]
      Console.WriteLine("v2 = {0}", v2.ToString())   v2 = [0 1 0 1 0]

      Summing v1 and v2 will yield a vector of all 1s.
      Dim sum As FloatVector = v1 + v2
      Console.WriteLine("v1 + v2 = {0}", sum.ToString())   v1 + v2 = [1 1 1 1 1]

      Vector scalar operators are also provided.
      Dim a As Single = 2
      Dim asum As FloatVector = v1 + (a * v2)
      Console.WriteLine("v1 + a*v2 = {0}", asum.ToString())   v1 + a*v2 = [1 2 1 2 1]

      If we increase the length of v1 and try to multiply with v2, we
      will get a MismatchedSizeException. Vectors must have the same
      length to be combined using the element-wise operators.
      v1.Resize(length + 1)
      Dim product As FloatVector
      Try
        product = v1 * v2
      Catch e As MismatchedSizeException
        Console.WriteLine("Oops - " + e.Message)
      End Try

      Increment and decrement operators have been overloaded too.
      Console.WriteLine("v2 = {0}", v2.ToString())
      v2 = FloatVector.Increment(v2)
      Console.WriteLine("v2++ = {0}", v2.ToString())

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

    End Sub

  End Module

End Namespace