Package no.uib.cipr.matrix.sparse
Class ILUT
java.lang.Object
no.uib.cipr.matrix.sparse.ILUT
- All Implemented Interfaces:
Preconditioner
ILU preconditioner with fill-in. Uses the dual threshold approach of Saad.
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Constructor Summary
ConstructorsConstructorDescriptionSets up the preconditioner for the given matrix.ILUT
(FlexCompRowMatrix LU, double tau, int p) Sets up the preconditioner for the given matrix -
Method Summary
Modifier and TypeMethodDescriptionSolves the approximate problem with the given right hand side.void
Sets the operator matrix for the preconditioner.transApply
(Vector b, Vector x) Solves the approximate transpose problem with the given right hand side.
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Constructor Details
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ILUT
Sets up the preconditioner for the given matrix- Parameters:
LU
- Matrix to use internally. For best performance, its non-zero pattern should conform to that of the system matrixtau
- Drop tolerancep
- Number of entries to keep on each row in of the factored matrix. This is in addition to the entries of the original matrix
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ILUT
Sets up the preconditioner for the given matrix. Uses a drop-tolerance of 10-6, and keeps 50 entries on each row, including the main diagonal and any previous entries in the matrix structure- Parameters:
LU
- Matrix to use internally. For best performance, its non-zero pattern should conform to that of the system matrix
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Method Details
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apply
Description copied from interface:Preconditioner
Solves the approximate problem with the given right hand side. Result is stored in given solution vector- Specified by:
apply
in interfacePreconditioner
- Parameters:
b
- Right hand side of problemx
- Result is stored here- Returns:
- x
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transApply
Description copied from interface:Preconditioner
Solves the approximate transpose problem with the given right hand side. Result is stored in given solution vector- Specified by:
transApply
in interfacePreconditioner
- Parameters:
b
- Right hand side of problemx
- Result is stored here- Returns:
- x
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setMatrix
Description copied from interface:Preconditioner
Sets the operator matrix for the preconditioner. This method must be called before a preconditioner is used by an iterative solver- Specified by:
setMatrix
in interfacePreconditioner
- Parameters:
A
- Matrix to setup the preconditioner for. Not modified
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