Cubic splines

[Eric Desart]

Sorry all,

A dumb question.
I was searching the Excel groups for a Cubic spline smoothing.

I find numerous messages refering to code entered by David Braden.
In some I find a link:

Most (all?) look like this:
http://groups.google.com/[email protected]

But this leads nowhere.

Can somebody help me locating this code?
I really tried myself.

TIA
Eric

 

[Debra Dalgleish]

Try this link instead:

http://groups.google.ca/[email protected]

 

[Eric Desart]

Hello Debra,

A million thanks .... that one works.

I tried again in Ron de Bruyn's Google search and via Google.com by
literally copying text from the David Braden post as text and they couldn't
find it.

You helped me a lot.
And thanks to David to.

Kind regards
Eric

PS: maybe an idea for David to reenter that post that google.com can find it
too. (it's often referred to).

 

[Tom Ogilvy]

I don't think David has posted in at least 6 months or more, so his
interests must lie elsewhere, at least for the present.

But you have been a bit of a stranger as well.

 

[Dana DeLouis]

Eric. Just for feedback, David's code works really well! For example, he
gave 7 data points for testing, with x values running from 1-7.
As a custom function, the Cubic Spline equations of that test data would be
the following: The returned values match David exactly. :>)

Function Spline(num)
Dim t, n
n = num - Int(num)

Select Case num
Case Is < 1
t = "#N/A"
Case Is < 2
t = 3 + (21 * n) / 26 - (21 * n ^ 3) / 26
Case Is < 3
t = 3 - (21 * n) / 13 - (63 * n ^ 2) / 26 + (53 * n ^ 3) / 26
Case Is < 4
t = 1 - (9 * n) / 26 + (48 * n ^ 2) / 13 - (61 * n ^ 3) / 26
Case Is < 5
t = 2 - (87 * n ^ 2) / 26 + (61 * n ^ 3) / 26
Case Is < 6
t = 1 + (9 * n) / 26 + (48 * n ^ 2) / 13 - (53 * n ^ 3) / 26
Case Is <= 7
t = 3 + (21 * n) / 13 - (63 * n ^ 2) / 26 + (21 * n ^ 3) / 26
Case Else
t = "#N/A"
End Select

Spline = t
End Function


--
Dana DeLouis
Win XP & Office 2003

Hello Debra,

A million thanks .... that one works.

I tried again in Ron de Bruyn's Google search and via Google.com by
literally copying text from the David Braden post as text and they
couldn't
find it.

You helped me a lot.
And thanks to David to.

Kind regards
Eric

PS: maybe an idea for David to reenter that post that google.com can find
it
too. (it's often referred to).

 

[Eric Desart]

Thanks Tom & Dana,

I'll play with David's code next weekend.
Tom I know I've been busy.

But to smooth my consience a bit.
I still help people a lot with physical acoustics in studio groups.
In Excel I'm still stuck with a lot of old macro4 programs.

Dana,
checking your function, it seems I still must search how to make those
formulas for n numbers of x.
Must take some time to better understand.

Warm regards
Eric