[FLASH-BUGS] Species Flux Handling with USM MHD in FLASH 4.3

[Jason Galyardt]

Dear FLASH Developers,

I've just started using FLASH 4.3 with the USM MHD solver, and I've noticed
some ungraceful behavior to do with species flux handling. When I use
hy_fullSpecMsFluxHandling=.true. (the default), FLASH crashes with a
segmentation violation right after writing the initial checkpoint and plot
files. Here's the traceback I get for one process in debug mode:

forrtl: severe (174): SIGSEGV, segmentation fault occurred
Image              PC                Routine            Line
Source
libintlc.so.5      00002AB348C8C1F9  Unknown               Unknown  Unknown
libintlc.so.5      00002AB348C8AB70  Unknown               Unknown  Unknown
libifcore.so.5     00002AB347AF7DDF  Unknown               Unknown  Unknown
libifcore.so.5     00002AB347A5F4CF  Unknown               Unknown  Unknown
libifcore.so.5     00002AB347A70BC3  Unknown               Unknown  Unknown
libpthread.so.0    000000308D00ECA0  Unknown               Unknown  Unknown
flash4             000000000112A509  hy_uhd_datarecons         366
hy_uhd_DataReconstructNormalDir_MH.F90
flash4             00000000012F58C4  hy_uhd_datarecons         535
hy_uhd_dataReconstOneStep.F90
flash4             00000000015AAD98  hy_uhd_getriemann         621
hy_uhd_getRiemannState.F90
flash4             00000000016AC695  hy_uhd_unsplit_           494
hy_uhd_unsplit.F90
flash4             000000000075A25D  hydro_                     67
Hydro.F90
flash4             00000000004A289D  driver_evolveflas         287
Driver_evolveFlash.F90
flash4             0000000000503EE1  MAIN__                     51
Flash.F90
flash4             000000000041A176  Unknown               Unknown  Unknown
libc.so.6          000000308C41D9C4  Unknown               Unknown  Unknown
flash4             000000000041A079  Unknown               Unknown  Unknown

I've checked line 366 of hy_uhd_DataReconstructNormalDir_MH.F90, but I
couldn't find any obvious incidences of array indices being out of bounds.

When I set hy_fullSpecMsFluxHandling=.false. in my flash.par file, the
crash does not happen (which is what I expect, looking at the source file
in question). Since this parameter defaults to .true., I would expect it to
play nice with USM. If it's behavior is expected to be unpredictable,
perhaps we need a warning to that effect (or simply set it to .false. when
USM is in use).

I'm using the Intel Fortran compiler version 14.0.0.080. For reference,
here's my setup line:

./setup magnetoHD/SmithMotion -auto -3d -maxblocks=600 +usm
nonIdealMHD=True withDarkMatter=False gravMode=1 withNEI=True
-objdir=smithMotion_NoDM_nonIdealB_dbug -makefile=intel -debug

Note that I've defined the setup flags nonIdealMHD, withDarkMatter,
gravMode, and withNEI in the Config file for my simulation.

Please let me know if you need additional information.

Best Regards,
Jason

----
Jason Galyardt
Department of Physics & Astronomy
University of Georgia
Athens, GA, USA
jeg at uga.edu