[Python-Dev] Math.sqrt(-1) -- nan or ValueError?

Guido van Rossum guido at python.org
Tue Sep 4 23:58:27 CEST 2007

Is this on OSX? That test has been failing (because on that platform
sqrt(-1) returns nan instead of raising ValueError) for years -- but
the test is only run when run in verbose mode, which mostly hides the
issue.  Have you read the comment for the test?

On 9/4/07, Hasan Diwan <hasan.diwan at gmail.com> wrote:
> I'm trying to fix a failing unit test in revision 57974. The test in
> question claims that math.sqrt(-1) should raise ValueError; the code itself
> gives "nan" as a result for that expression. I can modify the test and
> therefore have it pass, but I'm not sure if an exception would be more
> appropriate. I'd be happy for some direction here. Many thanks!

--Guido van Rossum (home page: http://www.python.org/~guido/)

More information about the Python-Dev mailing list