Sima: I did not mean to imply that the Formula Node will allow you to
create
a user-defined formula. You can't. All I was saying is that comparison
operations cannot be done with the VIs that you were trying to
use, and this was in the LabVIEW documentation. The "Eval" functions in
the Analyze->Mathematics->Formula section allow you to have
variable formulas, but based on the documentation none of these VIs
handle
comparison functions. For what you're doing you will probably need to
code up your own parser. Over the years I've seen various types of
formula parsers, so perhaps if you did a web search you might be able
to turn something up.
You didn't say how critical being able to do this is to your application. An alternate (though admittedly clumsy) solution may be to use the Matlab or Mathscript node. You can write out your function to a file and then have the Matlab/Mathscript node call the function. You can check the Matlab/Mathscript documentation on this, or just head over to the
MathScript forum.
