How to create formula with lookup table

[janijt]

Hi, I would like to convert formula in the below to labview format, any idea how this could be done easiest way?

I'm planning to use formula node but I'm not not sure about how to use lookup table inside the formula or is it even possible?

br, Jani

   
        Dim dblLookUp(,) As Double = New Double(3, 1) {{4, 4}, {10, 200}, {60, 3000}, {100, 7000}}
   
        If dblAbsValue >= 0 And dblAbsValue <= dblLookUp(0, 0) Then
            dblk = dblLookUp(0, 1) / dblLookUp(0, 0)
            dblValue = dblAbsValue * dblk
            'lblMode.Text = 1
        ElseIf dblAbsValue > dblLookUp(0, 0) And dblAbsValue <= dblLookUp(1, 0) Then
            dblk = (dblLookUp(1, 1) - dblLookUp(0, 1)) / (dblLookUp(1, 0) - dblLookUp(0, 0))
            dblValue = dblk * dblAbsValue - dblk * dblLookUp(0, 0) + dblLookUp(0, 1)
            'lblMode.Text = 2
        ElseIf dblAbsValue > dblLookUp(1, 0) And dblAbsValue <= dblLookUp(2, 0) Then
            dblk = (dblLookUp(2, 1) - dblLookUp(1, 1)) / (dblLookUp(2, 0) - dblLookUp(1, 0))
            dblValue = dblk * dblAbsValue - dblk * dblLookUp(1, 0) + dblLookUp(1, 1)
            'lblMode.Text = 3
        ElseIf dblAbsValue > dblLookUp(2, 0) And dblAbsValue <= dblLookUp(3, 0) Then
            dblk = (dblLookUp(3, 1) - dblLookUp(2, 1)) / (dblLookUp(3, 0) - dblLookUp(2, 0))
            dblValue = dblk * dblAbsValue - dblk * dblLookUp(2, 0) + dblLookUp(2, 1)
            'lblMode.Text = 4
        Else
            dblValue = dblLookUp(3, 1) '* Math.Sign(dblValue)
            'lblMode.Text = 5
        End If

        Return dblValue * intSign

[Andy_C. · Accepted solution]

Hello janijt,

You can definitely use formula node for it. What you would do is to create a constant array for the lookup table. 

Here's an implementation in MathScript Node

[janijt]

Thanks for help!

br, Jani

[GerdW]

Hi Jani,

does it have to be a formula node? This looks like it could be translated easily into native G...

[janijt]

Hi GerdW

No it does not, but I thinkthat formula node is easiest way to do it because calculation is not time critical.

 

br, Jani