Private Const MAX_CLUSTERS As Integer = 2
Private Const VECTORS As Integer = 4
Private Const VEC_LEN As Integer = 4
Private Const DECAY_RATE As Double = 0.96
Private Const MIN_ALPHA As Double = 0.01
Private Const CR As String = Chr(13) + Chr(10)

Private Alpha As Double = 0.6
Private D(MAX_CLUSTERS) As Double

Private w As Double(,) = New Double(,) {{0.2, 0.6, 0.5, 0.9}, _
                                        {0.8, 0.4, 0.7, 0.3}}

Private Pattern As Integer(,) = New Integer(,) {{1, 1, 0, 0}, _
                                                {0, 0, 0, 1}, _
                                                {1, 0, 0, 0}, _
                                                {0, 0, 1, 1}}

Private Tests As Integer(,) = New Integer(,) {{1, 0, 0, 1}, _
                                              {0, 1, 1, 0}, _
                                              {1, 0, 1, 0}, _
                                              {0, 1, 0, 1}}

Private Sub Training()
Dim Iterations As Integer = 0
Dim i As Integer
Dim VecNum As Integer
Dim DMin As Integer

    Do While Alpha > MIN_ALPHA
        Iterations += 1

        For VecNum = 0 To VECTORS - 1

            'Compute input.
            ComputeInput(VecNum)

            'See which is smaller, D(0) or D(1)?
            DMin = Minimum(D(0), D(1))
            'Text1.Text += "Closest is D(" + CStr(DMin) + ")" + CR

            'Update the weights on the winning unit.
            For i = 0 To VECTORS - 1
                w(DMin, i) = w(DMin, i) + (Alpha * (Pattern(VecNum, i) - w(DMin, i)))
                'Text1.Text += " w(" + CStr(i) + ")= " + CStr(w(DMin, i))
            Next i

        Next VecNum

        'Reduce the learning rate.
        Alpha = DECAY_RATE * Alpha

    Loop

    Text1.Text += "Iterations: " + CStr(Iterations) + CR + CR

End Sub

Private Sub Testing()
Dim i, j As Integer
Dim VecNum As Integer
Dim DMin As Integer

'Print clusters created.
    Text1.Text += "Clusters for training input:" + CR
    For VecNum = 0 To VECTORS - 1

        'Compute input.
        ComputeInput(VecNum)

        'See which is smaller, D(0) or D(1)?
        DMin = Minimum(D(0), D(1))

        Text1.Text += CR + "Vector ("
        For i = 0 To VECTORS - 1
            Text1.Text += CStr(Pattern(VecNum, i)) + ", "
        Next i
        Text1.Text += ") fits into category " + CStr(DMin) + CR

    Next VecNum

'Print weight matrix.
    Text1.Text += CR
    For i = 0 To MAX_CLUSTERS - 1
        Text1.Text += "Weights for Node " + CStr(i) + " connections:" + CR
        For j = 0 To VEC_LEN - 1
            Text1.Text += Microsoft.VisualBasic.Format(w(i, j), "#.000") + ", "
        Next
        Text1.Text += CR + CR
    Next

'Print post-training tests.
    Text1.Text += "Categorized test input:" + CR
    For VecNum = 0 To VECTORS - 1

        'Compute input.
        ComputeInput(VecNum)

        'See which is smaller, D(0) or D(1)?
        DMin = Minimum(D(0), D(1))

        Text1.Text += CR + "Vector ("
        For i = 0 To VECTORS - 1
            Text1.Text += CStr(Tests(VecNum, i)) + ", "
        Next i
        Text1.Text += ") fits into category " + CStr(DMin) + CR

    Next VecNum

End Sub

Private Sub ComputeInput(ByVal VectorNumber As Integer)
Dim i, j As Integer
    D(0) = 0.0
    D(1) = 0.0
    For i = 0 To MAX_CLUSTERS - 1
        For j = 0 To VECTORS - 1
            D(i) += (w(i, j) - Tests(VectorNumber, j)) ^ 2
            'Text1.Text += "D= " + CStr(D(i)) + CR
        Next j
    Next i
End Sub

Private Function Minimum(ByVal ValueA As Double, ByVal ValueB As Double) As Integer
    If ValueA > ValueB Then
        Minimum = 1
    ElseIf ValueA < ValueB Then
        Minimum = 0
    End If
End Function

Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) _
                                                            Handles Button1.Click
    Training()
    Testing()
End Sub