cern.colt.matrix.tfloat.algo.solver.preconditioner
Class FloatILUT

java.lang.Object
  cern.colt.matrix.tfloat.algo.solver.preconditioner.FloatILUT

All Implemented Interfaces:

FloatPreconditioner

public class FloatILUT
extends Object
implements FloatPreconditioner

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

Constructor Summary

FloatILUT(RCMFloatMatrix2D LU)
Sets up the preconditioner for the given matrix.

FloatILUT(RCMFloatMatrix2D LU, float tau, int p)
Sets up the preconditioner for the given matrix

Method Summary

FloatMatrix1D	apply(FloatMatrix1D b, FloatMatrix1D x) Solves the approximate problem with the given right hand side.
void	setMatrix(FloatMatrix2D A) Sets the operator matrix for the preconditioner.
FloatMatrix1D	transApply(FloatMatrix1D b, FloatMatrix1D x) Solves the approximate transpose problem with the given right hand side.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FloatILUT

public FloatILUT(RCMFloatMatrix2D LU,
                 float 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

FloatILUT

public FloatILUT(RCMFloatMatrix2D LU)

Sets up the preconditioner for the given matrix. Uses a drop-tolerance of 10^-6, and keeps 25 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 FloatMatrix1D apply(FloatMatrix1D b,
                           FloatMatrix1D x)

Description copied from interface: FloatPreconditioner

Solves the approximate problem with the given right hand side. Result is stored in given solution vector

Specified by:

apply in interface FloatPreconditioner

Parameters:

b - Right hand side of problem

x - Result is stored here

Returns:

x

transApply

public FloatMatrix1D transApply(FloatMatrix1D b,
                                FloatMatrix1D x)

Description copied from interface: FloatPreconditioner

Solves the approximate transpose problem with the given right hand side. Result is stored in given solution vector

Specified by:

transApply in interface FloatPreconditioner

Parameters:

b - Right hand side of problem

x - Result is stored here

Returns:

x

setMatrix

public void setMatrix(FloatMatrix2D A)

Description copied from interface: FloatPreconditioner

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 FloatPreconditioner

Parameters:

A - Matrix to setup the preconditioner for. Not modified