Get the star-forest to communicate multi-leaf block data


Collective the first time it is called

Input Parameter#

  • mapping - the mapping from local to global indexing

Output Parameter#


The returned star forest is suitable to exchange local information with other processes sharing the same global block index. For example, suppose a mapping with two processes has been created with

    rank 0 global block indices: [0, 1, 2]
    rank 1 global block indices: [2, 3, 4]

and we want to share the local information

    rank 0 data: [-1, -2, -3]
    rank 1 data: [1, 2, 3]

then, the broadcasting action of mlsf will allow to collect

    rank 0 mlleafdata: [-1, -2, -3, 3]
    rank 1 mlleafdata: [-3, 3, 1, 2]

Use ISLocalToGlobalMappingGetBlockNodeInfo() to index into the multi-leaf data.

See Also#

Low-level Vector Communication, ISLocalToGlobalMappingGetBlockNodeInfo(), PetscSF





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