[Date Index] [Thread Index] [Author Index]

Testing for unevaluated functions

• To: mathgroup at yoda.physics.unc.edu (Mathematica Group)
• Subject: Testing for unevaluated functions
• From: jake at skatter.usask.ca (Jason Breckenridge)
• Date: Mon, 28 Sep 92 19:42:54 CST

Hello mathgroup,

I have a question that I cannot seem to find the answer to in any of the Mma
books that I have available.

I would like to build a function that uses FindMinimum to search for a
minimum (obviously).  The problem is that as one varies one of the parameters
of the function, a definite min. will move outside of the range of the search.

I would like to test for this condition, and if Find Minimum cannot find a
minimum=, then use one of the endpoints.

The question is, is there no general mechanism for testing the return status
of a function, or at least a built-in function?

I would have thought tha there would be a way  to write something like:

If[UnevaluatedQ[FindMinimum[blah]], endpoint, FindMinimum[blah]]

but I can't seem to find anything about any sort of "UnevaluatedQ" in the 
various books.

Testing whether you get a list or not and then taking the list apart seems
a tad inelegant.

Thanks in advance for any info/suggestions.

jake