New Users Page

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Here you can find material on stuff we cover in our weekly meetings, or other interesting information about the AstroBEAR code.

SPECIAL TOPICS

Effectively Implementing AMR

There are some additional controls for AMR other than setting the number of levels in global.data. One can also make use of the namelist variable in physics.data named "refineVariableFactor". If this is not currently in your physics.data file, you can add it under the line for InterpOpts. The input for this variable represents the different q array elements (rho, px, py, pz, E, Bx, By, Bz, tracer1, tracer2, …, tracerM).

Example:

refineVariableFactor = 1.d-21,0d0,0d0,0d0,0d0,0d0,0d0,0d0,0d0,0d0,0d0,0d0,0d0

The input here controls the variable to which refinement is triggered. By setting a slot = 0 means that refinement will not be triggered for this variable. The smaller the number, the less the refinement. The max value for input to this array is 1, and if this line is not included in your physics.data, all the vector components will be initialized to 1.

refineVariableFactor is defined in module_control.f90, in the subroutine SetErrFlag.

Additionally, one can modify the SetErrFlags subroutine in problem.f90 to indicate precise regions of refinement.

Example:

Here, I am asking astrobear to refine within a sphere of r = clump_rad*0.1, where clump_rad is a module specific parameter. Now, all of the refinement will be restricted to this smaller region. This means, less cells, and less computational cost. (A nice reference on cost is here: Tutorials/JobSizes).

Helpful Links

​http://www.mpia.de/homes/dullemon/lectures/fluiddynamics/Chapter_5.pdf - Nicely composed introduction chapter on numerical hydrodynamics.