Public Member Functions | |
AdditionalData (const double omega=1, const double min_diagonal=0, const unsigned int overlap=0) | |
Public Attributes | |
double | omega |
double | min_diagonal |
unsigned int | overlap |
omega
specifies the relaxation parameter in the SOR preconditioner. The parameter min_diagonal
can be used to make the application of the preconditioner also possible when some diagonal elements are zero. In a default application this would mean that we divide by zero, so by setting the parameter min_diagonal
to a small nonzero value the SOR will work on a matrix that is not too far away from the one we want to treat. Finally, overlap
governs the overlap of the partitions when the preconditioner runs in parallel, forming a so-called additive Schwarz preconditioner. TrilinosWrappers::PreconditionSOR::AdditionalData::AdditionalData | ( | const double | omega = 1 , |
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const double | min_diagonal = 0 , |
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const unsigned int | overlap = 0 | |||
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Constructor. By default, set the damping parameter to one, we do not modify the diagonal, and there is no overlap (i.e. in parallel, we run a BlockJacobi preconditioner, where each block is inverted approximately by an SOR.
This specifies the (over-) relaxation parameter in the SOR preconditioner.
This specifies the minimum value the diagonal elements should have. This might be necessary when the SOR preconditioner is used on matrices with zero diagonal elements. In that case, a straight-forward application would not be possible since we divide by the diagonal element.
This determines how large the overlap of the local matrix portions on each processor in a parallel application should be.