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| IncompleteLUT () |
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template<typename MatrixType > |
| IncompleteLUT (const MatrixType &mat, const RealScalar &droptol=NumTraits< Scalar >::dummy_precision(), int fillfactor=10) |
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EIGEN_CONSTEXPR Index | rows () const EIGEN_NOEXCEPT |
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EIGEN_CONSTEXPR Index | cols () const EIGEN_NOEXCEPT |
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ComputationInfo | info () const |
| Reports whether previous computation was successful. More...
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template<typename MatrixType > |
void | analyzePattern (const MatrixType &amat) |
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template<typename MatrixType > |
void | factorize (const MatrixType &amat) |
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template<typename MatrixType > |
IncompleteLUT & | compute (const MatrixType &amat) |
| Compute an incomplete LU factorization with dual threshold on the matrix mat No pivoting is done in this version. More...
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void | setDroptol (const RealScalar &droptol) |
| Set control parameter droptol. More...
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void | setFillfactor (int fillfactor) |
| Set control parameter fillfactor. More...
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template<typename Rhs , typename Dest > |
void | _solve_impl (const Rhs &b, Dest &x) const |
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template<typename _MatrixType > |
void | analyzePattern (const _MatrixType &amat) |
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template<typename _MatrixType > |
void | factorize (const _MatrixType &amat) |
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| SparseSolverBase () |
| Default constructor. More...
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| ~SparseSolverBase () |
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IncompleteLUT< _Scalar, int > & | derived () |
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const IncompleteLUT< _Scalar, int > & | derived () const |
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const Solve< IncompleteLUT< _Scalar, int >, Rhs > | solve (const MatrixBase< Rhs > &b) const |
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const Solve< IncompleteLUT< _Scalar, int >, Rhs > | solve (const SparseMatrixBase< Rhs > &b) const |
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void | _solve_impl (const SparseMatrixBase< Rhs > &b, SparseMatrixBase< Dest > &dest) const |
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template<typename _Scalar, typename _StorageIndex = int>
class Eigen::IncompleteLUT< _Scalar, _StorageIndex >
Incomplete LU factorization with dual-threshold strategy.
\implsparsesolverconcept
During the numerical factorization, two dropping rules are used : 1) any element whose magnitude is less than some tolerance is dropped. This tolerance is obtained by multiplying the input tolerance droptol
by the average magnitude of all the original elements in the current row. 2) After the elimination of the row, only the fill
largest elements in the L part and the fill
largest elements in the U part are kept (in addition to the diagonal element ). Note that fill
is computed from the input parameter fillfactor
which is used the ratio to control the fill_in relatively to the initial number of nonzero elements.
The two extreme cases are when droptol=0
(to keep all the fill*2
largest elements) and when fill=n/2
with droptol
being different to zero.
References : Yousef Saad, ILUT: A dual threshold incomplete LU factorization, Numerical Linear Algebra with Applications, 1(4), pp 387-402, 1994.
NOTE : The following implementation is derived from the ILUT implementation in the SPARSKIT package, Copyright (C) 2005, the Regents of the University of Minnesota released under the terms of the GNU LGPL: http://www-users.cs.umn.edu/~saad/software/SPARSKIT/README However, Yousef Saad gave us permission to relicense his ILUT code to MPL2. See the Eigen mailing list archive, thread: ILUT, date: July 8, 2012: http://listengine.tuxfamily.org/lists.tuxfamily.org/eigen/2012/07/msg00064.html alternatively, on GMANE: http://comments.gmane.org/gmane.comp.lib.eigen/3302