Spreadsheet and VBA For Lissajous Curves

[wellinth]

Lissajous curves are defined by x = a*sin(theta) and y = b*sin(theta). I created a macro enabled Excel spreadsheet to draw them. I can send it to anyone with instructions on how to use it. The spreadsheet uses the VBA code below.

I'll be glad to answer any questions about this. Hope this post helps.

- Tom

Public Sub lissajous()
'Creates data points to draw a Lissajous curve
Dim a As Integer, b As Integer
Dim theta As Double, stepsize As Double, iter As Long
Dim pi2 As Double

'Read a and b from the spreadsheet
'if they are not positive then say so and exit



a = Int(Val(Cells(3, 2).Value))
b = Int(Val(Cells(4, 2).Value))



If a <= 0 Or b <= 0 Or Cells(9, 12).Value Or Cells(10, 12).Value Then

MsgBox "a and b must be positive integers. Try again.", vbExclamation

Else

'Initialize counters, steps, clear ranges and set headings.
theta = 0#
iter = 0
stepsize = Val(Cells(5, 2).Value)
pi2 = 2 * WorksheetFunction.Pi
Range("D:G").ClearContents

Cells(1, 4).Value = "Iteration"
Cells(1, 5).Value = "Step"
Cells(1, 6).Value = "Sin(" & CStr(a) & "* theta)"
Cells(1, 7).Value = "Sin(" & CStr(b) & "* theta)"


'Loop through all values in 0 to 2pi with a stepsize of stepsize
'Create data for plotting

While theta <= pi2
iter = iter + 1
Cells(1 + iter, 4).Value = iter
Cells(1 + iter, 5).Value = theta
Cells(1 + iter, 6).Value = Sin(a * theta)
Cells(1 + iter, 7).Value = Sin(b * theta)

theta = theta + stepsize

Wend

End If


End Sub