Random Swap Mutation Operator

' This is like single swap, but swaps a random string of consecutive values instead

        ' Doubles(0) = Minimum Swap Size [0, 0.33]
        ' Doubles(1) = Maximum Swap Size [0, 0.33]

        'This will generate the Y value for the ChildMutationWithRandomSizedSwaps function
        Public Function RSS_GetY(ByRef randswapsize As Integer, ByVal XPos As Integer)
            Dim done As Boolean = False

            'Need to determine the start, end, and width of the invalid area.
            'Special case: when X is between 0 and randomswapsize - 1
            'Start and End of invalid area variables refer to indexes 
            Dim StartofInvalidArea, WidthofInvalidArea As Integer
            Dim LeftNumberofValid, RightNumberofValid, EndofInvalidArea As Integer
            StartofInvalidArea = XPos - randswapsize + 1
            If (StartofInvalidArea < 0) Then 'If start pos of invalid area < 0 then it corrects itself + corrects width of invalid area
                Dim temp22 As Integer = StartofInvalidArea * -1
                StartofInvalidArea = 0
                WidthofInvalidArea = (randswapsize + randswapsize - 1) - temp22
            Else
                WidthofInvalidArea = randswapsize + randswapsize - 1
            End If
            EndofInvalidArea = StartofInvalidArea + WidthofInvalidArea - 1

            'Determine the quantity of valid spots for Y to the left and right of the invalid area
            '  LeftNumberofValid refers to quantity of valid values left of the invalid area
            '  Rightnumberofvalid refrs to quantity of valid values right of the invalid area
            LeftNumberofValid = StartofInvalidArea
            RightNumberofValid = (AlleleCount - randswapsize) - LeftNumberofValid - WidthofInvalidArea + 1
            If (LeftNumberofValid < 0) Then 'if left number of valid less than zero then set to 0
                LeftNumberofValid = 0
            End If
            If (RightNumberofValid < 0) Then 'if right number of valid less than zero then set to 0
                RightNumberofValid = 0
            End If

            'Y can either be on the left of the invalid area or the right
            '  Depending on the random number generated, Y will end up on either side
            Dim StartYPos As Integer = RAND.Next(0, (LeftNumberofValid + RightNumberofValid - 1))
            If (StartYPos < LeftNumberofValid) Then
                Return StartYPos
            Else
                StartYPos = EndofInvalidArea + (StartYPos - LeftNumberofValid) + 1
                Return StartYPos
            End If
        End Function

        Public Sub RandomSwap_Mutation(ByRef Child1 As PChromo)
            Dim K As Integer

            'X refers to the starting index of the first swap area
            'Y refers to the starting index of the second swap area
            'These areas are "randomwapsize" long
            Dim randswapsize = RAND.Next(RandomSwap_Master.Doubles(0) * AlleleCount, RandomSwap_Master.Doubles(1) * AlleleCount) 'Doubles(0) = min swap size || Doubles(1) = max swap size
            Dim X As Integer = RAND.Next(0, AlleleCount - randswapsize)
            Dim Y As Integer = RSS_GetY(randswapsize, X) 'Calls purpose built function for determining Y value

            'Swap the Values
            For counter As Integer = 0 To (randswapsize - 1)
                K = Child1.Alleles(X + counter)
                Child1.Alleles(X + counter) = Child1.Alleles(Y + counter)
                Child1.Alleles(Y + counter) = K
            Next
        End Sub