help on UDF code

[Guest]

I have the following code to create a UDF to calculate reciprocals:

Function Reciprocal(a)
Reciprocal(a) = (1 / a)
End Function

The code is in a module.

I get #VALUE! errors when I try to run it. So I think this means that Excel
recognizes the UDF (otherwise it would return a #NAME error, right?)

So what's the problem here?

 

[Guest]

Avoid the appearance of recursion:

Function Reciprocal(a)
Reciprocal = (1 / a)
End Function

 

[Guest]

OK, that works, thanks.

What do you mean by the appearance of recursion?

 

[Guest]

There are some functions that are actually defined in term of themselves.
Factorials or Ackerman's function for example. See:


http://www.nist.gov/dads/HTML/ackermann.html