ILUTPPreconditioner Class

This class performs an Incomplete LU factorization with drop tolerance and partial pivoting. The drop tolerance indicates which additional entries will be dropped from the factorized LU matrices.

Inheritance Hierarchy

SystemObject
Altaxo.Calc.LinearAlgebra.Double.SolversILUTPPreconditioner

Namespace: Altaxo.Calc.LinearAlgebra.Double.Solvers
Assembly: AltaxoCore (in AltaxoCore.dll) Version: 4.8.3179.0 (4.8.3179.0)

Syntax

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public sealed class ILUTPPreconditioner : IPreconditioner<double>

The ILUTPPreconditioner type exposes the following members.

Constructors

	Name	Description
	ILUTPPreconditioner	Initializes a new instance of the ILUTPPreconditioner class with the default settings.
	ILUTPPreconditioner(Double, Double, Double)	Initializes a new instance of the ILUTPPreconditioner class with the specified settings.

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Properties

	Name	Description
	DropTolerance	Gets or sets the absolute drop tolerance which indicates below what absolute value an entry will be dropped from the matrix. The standard value is 0.0001.
	FillLevel	Gets or sets the amount of fill that is allowed in the matrix. The value is a fraction of the number of non-zero entries in the original matrix. The standard value is 200.
	PivotTolerance	Gets or sets the pivot tolerance which indicates at what level pivoting will take place. The standard value is 0.0 which means pivoting will never take place.

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Methods

	Name	Description
	Approximate	Approximates the solution to the matrix equation Ax = b.
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object)
	GetHashCode	Serves as the default hash function. (Inherited from Object)
	GetType	Gets the Type of the current instance. (Inherited from Object)
	Initialize	Initializes the preconditioner and loads the internal data structures.
	ToString	Returns a string that represents the current object. (Inherited from Object)

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Fields

	Name	Description
	DefaultDropTolerance	The default drop tolerance.
	DefaultFillLevel	The default fill level.

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Remarks

The ILUTP-Mem algorithm was taken from:
ILUTP_Mem: a Space-Efficient Incomplete LU Preconditioner
Tzu-Yi Chen, Department of Mathematics and Computer Science,
Pomona College, Claremont CA 91711, USA
Published in:
Lecture Notes in Computer Science
Volume 3046 / 2004
pp. 20 - 28
Algorithm is described in Section 2, page 22

Reference

Altaxo.Calc.LinearAlgebra.Double.Solvers Namespace