Description of ILU

ILU<Matrix>		Programmers Guide
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Category:itl,functors

Component type:type

Description

Usage: Matrix A; ILU precond(A); qmr(A, x, b, precond.left(), precond.right(), iter); Matrix has to be unsymmetric. For symmetric one, use incomlete cholesky. Notes: The idea under a concrete Preconditioner such as Incomplete Cholesky is to create a Preconditioner object to use in iterative methods.

Example

In ilu.cpp:

typedef matrix< Type, rectangle<>, 
	        array< compressed<> >, 
                row_major >::type Matrix;
  Matrix A(5, 5);
  dense1D<Type> x(A.nrows(), Type(0));
  dense1D<Type> b(A.ncols());
  for (dense1D<Type>::iterator i=b.begin(); i!=b.end(); i++)
    *i = 1.;
  // ilu preconditioner 
  ILU<Matrix> precond(A);
  //iteration
  noisy_iteration<double> iter(b, max_iter, 1.e-6);
  //qmr algorithm
  qmr(A, x, b, precond.left(), precond.right(), iter);

Definition

ilu.h

Template Parameters

Parameter	Description	Default
`Matrix`	An MTL Matrix

Model of

Members

Member	Where defined	Description
`Precond`		The preconditioner type
`Left`		The left preconditioner type
`Right`		The right preconditioner type
`ILU ()`		Default Constructor
`ILU (const Matrix& A_)`		Construct from Matrix A
`Precond operator() ()`		return a left or right Preconditioner object.
`Left left ()`		return the left part of a Split Preconditioner object
`Right right ()`		return the right part of a Split Preconditioner object
`void print ()`

New members

Notes

See also