petsc-master 2016-10-20
Report Typos and Errors


Relative threshold to use for dropping edges in aggregation graph


#include "petscpc.h" 
PetscErrorCode PCGAMGSetThreshold(PC pc, PetscReal n)
Not collective on PC

Input Parameters

pc - the preconditioner context
threshold - the threshold value, 0.0 means keep all nonzero entries in the graph; negative means keep even zero entries in the graph

Options Database Key

-pc_gamg_threshold <threshold> - Notes: Before aggregating the graph GAMG will remove small values from the graph thus reducing the coupling in the graph and a different (perhaps better) coarser set of points.

See Also


Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages