no.uib.cipr.matrix.sparse
Class ILUT

java.lang.Object
  extended by no.uib.cipr.matrix.sparse.ILUT
All Implemented Interfaces:
Preconditioner

public class ILUT
extends java.lang.Object
implements Preconditioner

ILU preconditioner with fill-in. Uses the dual threshold approach of Saad.


Constructor Summary
ILUT(FlexCompRowMatrix LU)
          Sets up the preconditioner for the given matrix.
ILUT(FlexCompRowMatrix LU, double tau, int p)
          Sets up the preconditioner for the given matrix
 
Method Summary
 Vector apply(Vector b, Vector x)
          Solves the approximate problem with the given right hand side.
 void setMatrix(Matrix A)
          Sets the operator matrix for the preconditioner.
 Vector transApply(Vector b, Vector x)
          Solves the approximate transpose problem with the given right hand side.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ILUT

public ILUT(FlexCompRowMatrix LU,
            double tau,
            int p)
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 matrix
tau - Drop tolerance
p - Number of entries to keep on each row in of the factored matrix. This is in addition to the entries of the original matrix

ILUT

public ILUT(FlexCompRowMatrix LU)
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
Method Detail

apply

public Vector apply(Vector b,
                    Vector x)
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 interface Preconditioner
Parameters:
b - Right hand side of problem
x - Result is stored here
Returns:
x

transApply

public Vector transApply(Vector b,
                         Vector x)
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 interface Preconditioner
Parameters:
b - Right hand side of problem
x - Result is stored here
Returns:
x

setMatrix

public void setMatrix(Matrix A)
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 interface Preconditioner
Parameters:
A - Matrix to setup the preconditioner for. Not modified