On 5 Nov 2010, at 17:40, Frank Loeffler wrote:
On Fri, Nov 05, 2010 at 05:32:49PM +0100, Ian Hinder wrote:
I have also noticed that the WeylScal4 test is newly failing as of last night.
This one.
I modified the parameter files yesterday to remove the Carpet::poison_value parameter as the new Mercurial version of Carpet doesn't understand that parameter. The test passed on my laptop so I committed the new parameter file, but it seems to fail with NaNs on Damiana. I'm looking into it now.
Roland is as well. The problem doesn't seem to come from Weylscal4 itself, because already the evolved metric develops NaNs. Looking at the used refinement levels I would guess that they are simply too small, without enough space between them.
That sounds likely. It's probably a good idea to use NaN as the poison value (which is the default) in all test suites. For production runs, it's useful to have an identifiable non-NaN value because (a) it propagates more slowly, meaning that it can be seen when visualising data output every few iterations, and (b) because you can tell that it comes from a bug rather than a numerical problem. But in a test suite, we want any failure to be as obvious as possible, and a NaN is a good way to get a problem noticed. For example, any norm output would be sensitive to it.