petsc-3.7.5 2017-01-01

PCREDISTRIBUTE

Redistributes a matrix for load balancing, removing the rows that only have a diagonal entry and then applys a KSP to that new matrix Options for the redistribute preconditioners can be set with -redistribute_ksp_xxx <values> and -redistribute_pc_xxx <values>

Notes: Usually run this with -ksp_type preonly

If you have used MatZeroRows() to eliminate (for example, Dirichlet) boundary conditions for a symmetric problem then you can use, for example, -ksp_type preonly -pc_type redistribute -redistribute_ksp_type cg -redistribute_pc_type bjacobi -redistribute_sub_pc_type icc to take advantage of the symmetry.

This does NOT call a partitioner to reorder rows to lower communication; the ordering of the rows in the original matrix and redistributed matrix is the same.

Developer Notes: Should add an option to this preconditioner to use a partitioner to redistribute the rows to lower communication.

PCREDISTRIBUTE

See Also