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Whisky: Problems and how to fix them
CompilingWhen using the GetCactus script it puts the MoL directories in the wrong places.This is a problem with old versions of the script. Download the latest version and it should be fixed.When compiling on a Linux machine there are numerous errors in compiling a Fortran routine (favourites include NewRad.F or Sources.F in BSSN_MoL, or ADMConstraints.F in ADMConstraints). One of the first errors says invalid character in label field.This is a problem (which isn't strictly a bug) with the C preprocessor. Two possible solutions are given on the Cactus web pages.When compiling on a non-Linux machine there are numerous errors as above.This usually indicates that I forgot to include a carriage return at the end of a file in Whisky. I hope that I've found all of these by now; if updating the distribution doesn't help then complain to me.RunningThe code stops, complaining about the stencil width.The size of the ghost zones needs to be correct both in Whisky and in the driver. These are changed by the parameters whisky::whisky_stencil and driver::ghost_size. These must be at least 2. For PPM these must be at least 3. When ENO is implemented they must be at least the order of the ENO reconstruction.Trying to run a "lower dimensional" test by reducing the size of the box suddenly stops it doing any evolution.Cactus uses internal ghosts zones. So to run a "1d" test in the x direction you would set driver::global_ny to be 2*driver::ghost_size+1, and similarly for driver::global_nz.The code stops, complaining that the specific energy is below zero or the pressure has failed to converge.These errors occur in the routine that converts between conservative and primitive variables. The trouble is, it's difficult to tell whether this is caused by a bug or not. Various possibilities include
In an evolution, suddenly large parts of the domain are set to the atmosphere unphysically.This probably indicates that a NaN has occured in the update terms. The atmosphere condition forces this point to be reset, so the NaN is "quietly lost". Why a NaN should be produced is more complicated. Favourite possibilities are
When restoring a saved model in RNSID it produces nonsense initial data.There are two possibilities.
When running on a DEC machine the code stops in Whisky_TOVSolver complaining that the grid is too small, giving a nonsense number, or core dumps.This is a problem of the Digital Fortran 90 compiler; it's known to occur with version V5.2-705 which is installed on the holodec machines at the AEI. IH thinks that all the fixes are more dangerous than the current version, so this will not be changed. The thorn Whisky_TOVSolverC should be used instead.
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This page is maintained by Ian Hawke. |
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