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set whatis	"block-structured AMR framework"
set url		""
set license	"BSD"
set licensefile "license.txt"
set maintainer	"Achim Gsell <>"

set help	"
BoxLib contains all the functionality needed to write a parallel,
block-structured AMR application. The fundamental parallel abstraction is
the MultiFab, which holds the data on the union of grids at a level. A
MultiFab is composed of FAB's; each FAB is an array of data on a single
grid. During each MultiFab operation the FAB's composing that MultiFab are
distributed among the cores. MultiFab's at each level of refinement are
distributed independently. The software supports two data distribution
schemes, as well as a dynamic switching scheme that decides which approach
to use based on the number of grids at a level and the number of processors.
The first scheme is based on a heuristic knapsack algorithm; the second is
based on the use of a Morton-ordering space-filling curve. MultiFab
operations are performed with an owner computes rule with each processor
operating independently on its local data. For operations that require data
owned by other processors, the MultiFab operations are preceded by a data
exchange between processors. Each processor contains meta-data that is
needed to fully specify the geometry and processor assignments of the
MultiFab's. At a minimum, this requires the storage of an array of boxes
specifying the index space region for each AMR level of refinement. The
meta-data can thus be used to dynamically evaluate the necessary
communication patterns for sharing data amongst processors, enabling us to
optimize communications patterns within the algorithm. One of the advantages
of computing with fewer, larger grids in the hybrid OpenMP--MPI approach
is that the size of the meta-data is substantially reduced.

source		$env(PSI_LIBMODULES)