Imports System

Class Sample
  ' 任意の長さ・型の単位行列を生成する
  Shared Function CreateIdentityMatrix(ByVal length As Integer, ByVal typeOfMatrix As Type) As Array
    ' 指定された型でlength×length行列となる2次元配列を作成
    Dim matrix As Array = Array.CreateInstance(typeOfMatrix, length, length)

    ' 行列の対角成分に1、それ以外を0に設定する
    For i As Integer = 0 To length - 1
      For j As Integer = 0 To length - 1
        If i = j Then
          matrix.SetValue(1, i, j)
        Else
          matrix.SetValue(0, i, j)
        End If
      Next
    Next

    Return matrix
  End Function

  ' 行列を表示する
  Shared Sub PrintMatrix(ByVal matrix As Array)
    For i As Integer = 0 To matrix.GetLength(1) - 1
      Console.Write("(")
      For j As Integer = 0 To matrix.GetLength(0) - 1
        Console.Write("{0,-5} ", matrix.GetValue(i, j))
      Next
      Console.WriteLine(")")
    Next
  End Sub

  Shared Sub Main()
    ' Integer型で2行2列の単位行列を作成
    Dim matrix1 As Integer(,) = DirectCast(CreateIdentityMatrix(2, GetType(Integer)), Integer(,))

    PrintMatrix(matrix1)
    Console.WriteLine()

    ' Single型で4行4列の単位行列を作成
    Dim matrix2 As Single(,) = DirectCast(CreateIdentityMatrix(4, GetType(Single)), Single(,))

    ' 行列内の各要素をスケーリング
    For i As Integer = 0 To 3
      For j As Integer = 0 To 3
        matrix2(i, j) *= 0.25F
      Next
    Next

    PrintMatrix(matrix2)
    Console.WriteLine()
  End Sub
End Class

(1     0     )
(0     1     )

(0.25  0     0     0     )
(0     0.25  0     0     )
(0     0     0.25  0     )
(0     0     0     0.25  )