As an example,

For Each x In Range(rng.Address)

Range(rng.Address)
would refer to the activesheet when the calculation is performed (which may
not be the range intended)

You may have only one sheet in the workbook, but
why not
for each x in rng

--
Regards,
Tom Ogilvy

"Tom Ogilvy" wrote in message
...
if a UDF has an error, in xl97, it stops the calculation loop.

Perhaps one of you UDF's has an error.

--
Regards,
Tom Ogilvy


"David Murphy" wrote in message
...
I have adapted an algorithm for calculating the standard deviation of
levels (20Log(x)) in an Excel function. The function seems to work
correctly but when I reopen the workbook or even open a chart with the
SD values the workbook fails to recalculate sometimes. I use XL97. The
code is provided below. Does anyone have any suggestions?

' This function calculates the positive 2 standard deviation for a
collection of ranges
' Created 6/22/04
' By: Dave Murphy
'
Function SDPDB(ParamArray Levels()) As Variant
Application.Volatile
Dim rng As Variant, S As Double, A As Double, Sig As Double
Dim SigPdB As Double, SigMdB As Double, x As Variant, n As Integer, LA
As Double
A = 0
S = 0
n = 0
For Each rng In Levels()
For Each x In Range(rng.Address)
If Not IsEmpty(x) Then
A = A + 10 ^ (x / 20)
S = S + 10 ^ (x / 10)
n = n + 1
End If
Next x
Next rng
A = A / n
LA = 20 * Application.WorksheetFunction.Log10(A)
Sig = 1 / (n - 1) ^ 0.5 * (S - n * 10 ^ (LA / 10)) ^ 0.5
SDPDB = 20 * Application.WorksheetFunction.Log10(1 + 2 * Sig / A)
End Function

Thanks for any help,
Dave