nonsymmetric dynamics

class affects all levels in the multigrid hierarchy. There are two ways to change settings for
a particular level.
The first method for changing a setting on a particular level, such as level d, is to append
the string “(level d)” to the option string (note that a space must separate the option
and the level specification). For instance, assuming decreasing levels starting from 4, one
could set the aggregation schemes as follows:
MLList.set("aggregation: type","Uncoupled");
MLList.set("aggregation: type (level 1)","METIS");
MLList.set("aggregation: type (level 3)","MIS");
If the finest level is 0 and there are 5 levels, ML uses Uncoupled for levels 0, 2 and 4, METIS
for level 1 and MIS for level 3. Parameters that can be set differently on individual levels
are denoted with the symbol ⋆ (this symbol is not part of the parameter name).
The second method for changing a setting on a particular level is by using sublists.
Smoother sublists name must be of the form ”smoother: list (level XX)”, and aggregation
sublist names must be of the form ”aggregation: list (level XX)”, where XX is the level
number (0 is the finest). Parameter names in the sublist do not then need a level number.
Similarly, options for the coarsest level can be specified via the sublist ”coarse: list”. Below
is a short code fragment to illustrate this usage.
ParameterList MLList;
ParameterList &smList = MLList.sublist("smoother: list (level 1)");
smList.set("smoother: type","Jacobi");
smList.set("smoother: sweeps",5);
ParameterList &coarseList = MLList.sublist("coarse: list");
coarseList.set("coarse: type","symmetric Gauss-Seidel");
6.4.2 Parameter Validation
By default, the MultiLevelPreconditioner class validates the input parameter list. A parameter
that is misspelled/unknown or has an incorrect value type will cause an exception
to be thrown and execution to halt. Note that spaces are important within a parameter’s
name. Do not include non-required leading or trailing spaces. Please separate
words by just one space! The option ML print initial list prints the initial list
given to the MultiLevelPreconditioner constructor. The option ML print final list
prints the final list actually used by the MultiLevelPreconditioner constructor. One may
find it useful to print unused parameters by calling PrintUnused() after the construction
of the multilevel hierarchy.
6.4.3 General Options
ML output
[int] Controls the amount of printed information.
Ranges from 0 to 10 (0 is no output, and
10 is incredibly detailed output). Default: 0.
22