Reference documentation for deal.II version 9.4.0

#include <deal.II/lac/trilinos_precondition.h>
Public Member Functions  
AdditionalData (const double ilut_drop=0., const unsigned int ilut_fill=0, const double ilut_atol=0., const double ilut_rtol=1., const unsigned int overlap=0)  
Public Attributes  
double  ilut_drop 
unsigned int  ilut_fill 
double  ilut_atol 
double  ilut_rtol 
unsigned int  overlap 
Standardized data struct to pipe additional parameters to the preconditioner. The Trilinos ILUT decomposition allows for some fill in, so it actually is a threshold incomplete LU factorization. The amount of fillin, and hence, the amount of memory used by this preconditioner, is controlled by the parameters ilut_drop
and ilut_fill
, which specifies a threshold about which values should form the incomplete factorization and the level of additional fillin. When forming the preconditioner, for certain problems bad conditioning (or just bad luck) can cause the preconditioner to be very poorly conditioned. Hence it can help to add diagonal perturbations to the original matrix and form the preconditioner for this slightly better matrix. ilut_atol
is an absolute perturbation that is added to the diagonal before forming the prec, and ilu_rtol
is a scaling factor \(rtol \geq 1\). The last parameter specifies the overlap of the partitions when the preconditioner runs in parallel.
Definition at line 1099 of file trilinos_precondition.h.