Mercurial > octave-antonio
diff doc/interpreter/sparse.txi @ 5322:22994a5730f9
[project @ 2005-04-29 13:04:24 by dbateman]
author | dbateman |
---|---|
date | Fri, 29 Apr 2005 13:04:25 +0000 |
parents | 5bdc3f24cd5f |
children | d2d11284528e |
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--- a/doc/interpreter/sparse.txi Fri Apr 29 05:20:01 2005 +0000 +++ b/doc/interpreter/sparse.txi Fri Apr 29 13:04:25 2005 +0000 @@ -415,9 +415,10 @@ @sc{Octave} includes a poly-morphic solver for sparse matrices, where the exact solver used to factorize the matrix, depends on the properties -of the sparse matrix, itself. As the cost of determining the matrix type -is small relative to the cost of factorizing the matrix itself, the matrix -type is re-determined each time it is used in a linear equation. +of the sparse matrix, itself. The cost of determining the matrix type +is small relative to the cost of factorizing the matrix itself, but in any +case the matrix type is cached once it is calculated, so that it is not +re-determined each time it is used in a linear equation. The selection tree for how the linear equation is solve is @@ -456,11 +457,9 @@ @item If the matrix is upper or lower triangular perform a sparse forward or backward subsitution, and goto 9 -@item If the matrix is a permuted upper or lower triangular matrix, perform -a sparse forward or backward subsitution, and goto 9 - -FIXME: Detection of permuted triangular matrices not written yet, and so - the code itself is not tested either +@item If the matrix is a upper triangular matrix with column permutations +or lower triangular matrix with row permutations, perform a sparse forward +or backward subsitution, and goto 9 @item If the matrix is hermitian with a real positive diagonal, attempt sparse Cholesky factorization. @@ -494,6 +493,12 @@ In cases where, this might be a problem the user is recommended to disable the banded solvers as above, at a significant cost in terms of speed. +The user can force the type of the matrix with the @code{matrix_type} +function. This overcomes the cost of discovering the type of the matrix. +However, it should be noted incorrectly identifying the type of the matrix +will lead to unpredictable results, and so @code{matrix_type} should be +use dwith care. + @node Iterative Techniques, Oct-Files, Sparse Linear Algebra, Sparse Matrices @section Iterative Techniques applied to sparse matrices @@ -965,7 +970,7 @@ @item colperm Returns the column permutations such that the columns of `S (:, P)' are ordered in terms of increase number of non-zero elements. @item dmperm -Perfrom a Deulmage-Mendelsohn permutation on the sparse matrix S. +Perform a Deulmage-Mendelsohn permutation on the sparse matrix S. @item symamd For a symmetric positive definite matrix S, returns the permutation vector p such that `S (P, P)' tends to have a sparser Cholesky factor than S. @item symrcm @@ -979,12 +984,16 @@ @emph{Not implemented} @item eigs @emph{Not implemented} +@item matrix_type +Identify the matrix type or mark a matrix as a particular type. @item normest @emph{Not implemented} @item spdet Compute the determinant of sparse matrix A using UMFPACK. @item spinv Compute the inverse of the square matrix A. +@item spkron +Form the kronecker product of two sparse matrices. @item splu Compute the LU decomposition of the sparse matrix A, using subroutines from UMFPACK. @item sprank @@ -1066,6 +1075,8 @@ matrix. * luinc:: Produce the incomplete LU factorization of the sparse A. +* matrix_type:: Identify the matrix type or mark a matrix as a particular + type. * nnz:: returns number of non zero elements in SM See also: sparse * nonzeros:: Returns a vector of the non-zero values of the sparse matrix S @@ -1089,6 +1100,7 @@ * spfun:: Compute `f(X)' for the non-zero values of X This results in a sparse matrix with the same structure as X. * spinv:: Compute the inverse of the square matrix A. +* spkron:: Form the kronecker product of two sparse matrices. * splu:: Compute the LU decomposition of the sparse matrix A, using subroutines from UMFPACK. * spmax:: For a vector argument, return the maximum value. @@ -1147,12 +1159,17 @@ @DOCSTRING(issparse) -@node luinc, nnz, issparse, Function Reference +@node luinc, matrix_type, issparse, Function Reference @subsubsection luinc @DOCSTRING(luinc) -@node nnz, nonzeros, luinc, Function Reference +@node matrix_type, nnz, luinc, Function Reference +@subsubsection matrix_type + +@DOCSTRING(matrix_type) + +@node nnz, nonzeros, matrix_type, Function Reference @subsubsection nnz @DOCSTRING(nnz) @@ -1227,12 +1244,17 @@ @DOCSTRING(spfun) -@node spinv, splu, spfun, Function Reference +@node spinv, spkron, spfun, Function Reference @subsubsection spinv @DOCSTRING(spinv) -@node splu, spmax, spinv, Function Reference +@node spkron, splu, spinv, Function Reference +@subsubsection spkron + +@DOCSTRING(spkron) + +@node splu, spmax, spkron, Function Reference @subsubsection splu @DOCSTRING(splu)