[Users] OpenMP problem in Hydro_Analysis

[Erik Schnetter]

In the course of a private email discussion I found the following
problem. Since this may be of general interest I repeat my findings in
public. The discussion concerned possible OpenMP problems in GRHydro:

"The routine Hydro_Analysis_LocationSearch may return different
results with OpenMP. If one component contains multiple maxima, then
the last one is returned (without OpenMP), or a random one is returned
(with OpenMP). However, if several components contain the multiple
maxima, then the location of the maximum remains unset, i.e. at the
value it had at the last timestep.

"I suggest to switch off OpenMP in this routine, to insert a check
whether a single component contains multiple maxima and treat this the
same as when several components contain multiple maxima, and to set
the location of the maximum to a special error value (or to introduce
an error flag) so that it is obvious when the routine fails."

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>   http://www.cct.lsu.edu/~eschnett/