Computes the incomplete LU factorization of a sparse matrix in CSR format using a dual truncation mechanism. More...

Public Member Functions
subroutine	ilut (n, a, ja, ia, lfil, droptol, alu, jlu, ju, iwk, w, jw, ierr)

Detailed Description

Computes the incomplete LU factorization of a sparse matrix in CSR format using a dual truncation mechanism.

Parameters

[in]	n	The row dimension of the matrix.
[in]	a	The non-zero elements of matrix A.
[in]	ja	The column indices of matrix A.
[in]	ia	The index in A where the requested row starts.
[in]	lfil	The fill-in parameter. Each row of L and each row of U will have a maximum of `lfil` elements, excluding the diagonal element. `lfil` must be greater than or equal to zero.
[in]	droptol	The threshold for dropping small terms in the factorization.
[out]	alu	The factored matrix stored in Modified Sparse Row (MSR) format containing the L and U factors together. The diagonal, stored in ALU(1:N), is inverted. Each i-th row of the ALU, JLU matrix contains the i-th row of L, excluding the diagonal entry, followed by the i-th row of U.
[out]	jlu	The column indices for the factored matrix.
[out]	ju	An N-element array containing the pointers to the beginning of each row of U in the factored matrix.
[in]	iwk	The lengths of `alu` and `jlu`.
[out]	w	An N+1 element workspace array.
[out]	jw	A 2*N element workspace array.
[out]	ierr	Error flag: 0: Successful return .gt. 0: Zero pivot encountered at step number IERR. -1: Input matrix is incorrect. The elimination process generated a row in L or U whose length is greater than N. -2: The matrix L overflows the output array. -3: The matrix U overflows the output array. -4: Illegal value for @P lfil. -5: Zero-valued row encountered.

Definition at line 343 of file sparskit.f90.

Constructor & Destructor Documentation

subroutine sparskit::ilut::ilut	(	integer(int32), intent(in)	n,
		real(real64), dimension(*), intent(in)	a,
		integer(int32), dimension(*), intent(in)	ja,
		integer(int32), dimension(n+1), intent(in)	ia,
		integer(int32), intent(in)	lfil,
		real(real64), intent(in)	droptol,
		real(real64), dimension(*), intent(out)	alu,
		integer(int32), dimension(*), intent(out)	jlu,
		integer(int32), dimension(n), intent(out)	ju,
		integer(int32), intent(in)	iwk,
		real(real64), dimension(n+1), intent(out)	w,
		integer(int32), dimension(2*n), intent(out)	jw,
		integer(int32), intent(out)	ierr )

Definition at line 343 of file sparskit.f90.

The documentation for this interface was generated from the following file: