VB Database Example

Imports System
Imports System.Data

Imports CenterSpace.NMath.Core

Namespace CenterSpace.NMath.Examples.VisualBasic

  A .NET example in Visual Basic showing how to use ADO.NET data structures with matrices.
  Module DatabaseExample

    Sub Main()

      Console.WriteLine()

      Set up "database"
      Dim Table As New DataTable()
      Table.Columns.Add("column1", GetType(Double))
      Table.Columns.Add("column2", GetType(Double))
      Dim Values(1) As Object
      Values(0) = 4.5D
      Values(1) = 3.2D
      Table.Rows.Add(Values)
      Values(0) = -2.4D
      Values(1) = 99
      Table.Rows.Add(Values)

      Create matrix
      Dim A As New DoubleMatrix(Table)
      Console.WriteLine("A...")
      Console.WriteLine(A.ToTabDelimited())
      Console.WriteLine()

      Change matrix by incrementing
      DoubleMatrix.Increment(A)
      Console.WriteLine("A incremented...")
      Console.WriteLine(A.ToTabDelimited())
      Console.WriteLine()

      Refresh data table 
      Table = A.ToDataTable()

      Select rows where column1 is positive
      Dim Rows() As DataRow = Table.Select("column1 > 0")

      Make new matrix of resulting rows.
      A = New DoubleMatrix(Rows)
      Console.WriteLine("A from database...")
      Console.WriteLine(A.ToTabDelimited())

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

    End Sub

  End Module

End Namespace