Chapter 1 parallel sparse solver - freeFEM.org

22 CHAPTER 1. PARALLEL SPARSE SOLVER
iparms[0]
Solver identification:
0: BiCGStab, 1: GMRES, 2: PCG. By default=1
iparms[1]
Preconditioner identification:
0: BOOMER AMG, 1: PILUT, 2: Parasails, 3: Schwarz Default=0
iparms[2] Maximum of iteration: Default=1000
iparms[3] Krylov subspace dim: Default= 40
iparms[4] Solver print info level: Default=2
iparms[5] Solver log : Default=1
iparms[6] Solver stopping criteria only for BiCGStab : Default=1
dparms[0] Tolerance for convergence : De f ault = 1.0e − 11
Table 1.13: Definitions of common entries of iparms and dparms vectors for every preconditionner
in HYPRE
iparms[7] AMG interpolation type: Default=6
iparms[8]
Specifies the use of GSMG - geometrically
smooth coarsening and interpolation: Default=1
iparms[9] AMG coarsen type: Default=6
iparms[10]
Defines whether local or global measures
are used: Default=1
iparms[11] AMG cycle type: Default=1
iparms[12] AMG Smoother type: Default=1
iparms[13] AMG number of levels for smoothers: Default=3
iparms[14] AMG number of sweeps for smoothers: Default=2
iparms[15] Maximum number of multigrid levels: Default=25
Defines which variant of the Schwarz method is used:
0: hybrid multiplicative Schwarz method (no overlap across processor boundaries)
iparms[16]
1: hybrid additive Schwarz method (no overlap across processor boundaries)
2: additive Schwarz method
3: hybrid multiplicative Schwarz method (with overlap across processor boundaries)
Default=1
iparms[17] Size of the system of PDEs: Default=1
iparms[18] Overlap for the Schwarz method: Default=1
Type of domain used for the Schwarz method
iparms[19]
0: each point is a domain
1: each node is a domain (only of interest in “systems” AMG)
2: each domain is generated by agglomeration (default)
dparms[1] AMG strength threshold: Default=0.25
dparms[2] Truncation factor for the interpolation: Default=1e-2
dparms[3]
Sets a parameter to modify the definition
of strength for diagonal dominant portions of the matrix: Default=0.9
dparms[3]
Defines a smoothing parameter for the additive Schwarz method
Default=1.
Table 1.14: Definitions of other entries of iparms and dparms if preconditionner is BOOMER
AMG