Changes between Version 25 and Version 26 of PhysicsDataExplained
- Timestamp:
- 06/11/11 23:54:51 (14 years ago)
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PhysicsDataExplained
v25 v26 69 69 [[BR]] 70 70 71 == = MHD Variables ===71 == MHD Variables == 72 72 73 73 * '''''{{{lMHD:}}}''''' Logical switch used to turn MHD on or off. MHD requires the face-centered {{{aux}}} array, so if you turn MHD on, be sure to set {{{MaintainAuxArrays}}} in [GlobalDataExplained#GlobalData global.data] to {{{T}}}. … … 75 75 [[BR]] 76 76 77 == = Tracer Settings ===77 == Tracer Settings == 78 78 79 79 Tracer variables are used to track the movement of specific quantities of matter within your simulation. If, for instance, you had one or more clumps suspended in an ambient medium and wanted to track the way the clump matter moves through the domain, you would use a tracer. … … 86 86 * ''''''{{{NrTracerVars:}}}''''' Indicates the number of tracer variables to use in this problem. If {{{NrTracerVars}}} is {{{0}}}, then tracers will not be active. Tracking tracer variables costs memory and CPU cycles, so it's best to leave this switched off if you don't anticipate needing them. Under no circumstances should {{{NrTracerVars}}} be less than 0. 87 87 [[BR]] 88 89 == Non-Solver Variables == 90 91 AstroBEAR supports several specialized variables that are not handled by the solver. These variables are useful for debugging, but they are derived from AstroBEAR's operations rather than being calculated by the solver. These variables do not add significantly to the calculation cost per cell, but they do increase the memory load of AstroBEAR. As such, it's best to turn them off if you are not actively using them to debug your code. 92 93 All of the flags below are boolean: 94 95 * '''''{{{lCheckDivergence:}}}''''' Stores the divergence of the magnetic field. Ideally, this quantity should be 0, but when dealing with numerical approximations this is not always guaranteed. Nevertheless, high divergence values indicate serious problems with either the solver or the problem setup. 96 97 * '''''{{{lOutputErrFlag:}}}''''' Stores the error flags for a grid. This is useful when debugging unusual refinement patterns in your problem. 98 99 * '''''{{{lMPI_ID:}}}''''' Stores the MPI ID of a grid. It may seem redundant (since a grid can have only one MPI ID), but outputting it as a variable allows us to use visualization tools to see how AstroBEAR is distributing the grids.
