UDF inside UDF??

[ShelleyBelly]

Hi There,

Not sure if i'm asking the impossible but think i might just be.

i'm making a UDF and the algebra requires going to the Nth term, so instead of writing the same section of the formula over again i've written the architecture of it and then incorporated that as a UDF inside the former.

My question is, as the second UDF will only be used in conjunction with the first, is it possible to write it inside the first UDF.

Sorry for the poor explanation. Basically can you put a function inside another as below, or must they be separate??


Cheers



Function MP(Lat1)

'a = 6378137 ' Part of the WGS-84
'b = 6356752.3142 ' ellipsiod datum
f = 1 / 298.257223563

Lat1 = Radians(Lat1)

a = 21600 / (2 * Pi)
e = (2 * f - f ^ 2) ^ 0.5

Function Nth(n, Lat1)

Nth = e ^ (n + 1) / n * Sin(Lat1) ^ n

End Function


MP = a * Log(10) * Log10(Tan(Radians(45) + Lat1 / 2)) - a * (Nth(1, Lat1) + Nth(3, Lat1) + Nth(5, Lat1) + Nth(7, Lat1) + Nth(9, Lat1) + Nth(11, Lat1))

End Function

 

[shg]

You can't nest procedures within other procedures.

You could do it something like this, though I'm skeptical of the formula:

Option Explicit
Const pi          As Double = 3.14159265358979
Const D2R         As Double = pi / 180
Const f           As Double = 1 / 298.257223563
Const e           As Double = (2 * f - f ^ 2) ^ 0.5
Const a           As Double = 21600 / (2 * pi)
 
Function MP(ByVal Lat1 As Double)
    Lat1 = D2R * Lat1
    MP = a * Log(Tan(D2R * 45 + Lat1 / 2)) - _
         a * (Nth(1, Lat1) + Nth(3, Lat1) + Nth(5, Lat1) + Nth(7, Lat1) + Nth(9, Lat1) + Nth(11, Lat1))
End Function
 
Function Nth(n, Lat1)
    Nth = e ^ (n + 1) / n * Sin(Lat1) ^ n
End Function

Log in VBA is natural log.

EDIT: I'm skeptical of both formulas.