[GRASS-user] r.damflood and Courant-Friedrich-Lewy stability condition

[Panagiotis Mavrogiorgos]

Hi all,

In r.damflood if you try to run a calculation using invalid input you get a
warning WRT Courant-Friedrich-Lewy stability condition
<https://en.wikipedia.org/wiki/Courant%E2%80%93Friedrichs%E2%80%93Lewy_condition>.
If the wikipedia article is accurate and it is indeed a necessary condition
for convergence wouldn't it make sense to raise a fatal error (or whatever
is more appropriate) as soon as the condition isn't respected? I mean I
don't see much point in running a potentially lengthy simulation that will
give meaningless results. Am I wrong in this?

If my suggestion has indeed merit, could anyone suggest the most
appropriate way to do this?I don't mind submitting a patch but I am afraid
that I am not really familiar with GRASS C APIs.

These are the relevant lines:
https://trac.osgeo.org/grass/browser/grass-addons/grass7/raster/r.damflood/SWE.c#L504
https://trac.osgeo.org/grass/browser/grass-addons/grass7/raster/r.damflood/SWE.c#L708

thank you,
Panos
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