Functions File Reference

#include "defun-dld.h"
#include "error.h"
#include "gripes.h"
#include "oct-obj.h"
#include "utils.h"
#include "oct-map.h"
#include "MatrixType.h"
#include "SparseCmplxLU.h"
#include "SparsedbleLU.h"
#include "ov-re-sparse.h"
#include "ov-cx-sparse.h"
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 DEFUN_DLD (luinc, args, nargout,"-*- texinfo -*-\n\ @deftypefn {Loadable Function} {[@var{L}, @var{U}, @var{P}, @var{Q}] =} luinc (@var{A}, '0')\n\ @deftypefnx {Loadable Function} {[@var{L}, @var{U}, @var{P}, @var{Q}] =} luinc (@var{A}, @var{droptol})\n\ @deftypefnx {Loadable Function} {[@var{L}, @var{U}, @var{P}, @var{Q}] =} luinc (@var{A}, @var{opts})\n\ @cindex LU decomposition\n\ Produce the incomplete LU@tie{}factorization of the sparse matrix @var{A}.\n\ Two types of incomplete factorization are possible, and the type\n\ is determined by the second argument to @code{luinc}.\n\ \n\ Called with a second argument of '0', the zero-level incomplete\n\ LU@tie{}factorization is produced. This creates a factorization of @var{A}\n\ where the position of the non-zero arguments correspond to the same\n\ positions as in the matrix @var{A}.\n\ \n\ Alternatively, the fill-in of the incomplete LU@tie{}factorization can\n\ be controlled through the variable @var{droptol} or the structure\n\ @var{opts}. The @sc{umfpack} multifrontal factorization code by Tim A.\n\ Davis is used for the incomplete LU@tie{}factorization, (availability\n\ @url{})\n\ \n\ @var{droptol} determines the values below which the values in the\n\ LU@tie{} factorization are dropped and replaced by zero. It must be a\n\ positive scalar, and any values in the factorization whose absolute value\n\ are less than this value are dropped, expect if leaving them increase the\n\ sparsity of the matrix. Setting @var{droptol} to zero results in a complete\n\ LU@tie{}factorization which is the default.\n\ \n\ @var{opts} is a structure containing one or more of the fields\n\ \n\ @table @code\n\ @item droptol\n\ The drop tolerance as above. If @var{opts} only contains @code{droptol}\n\ then this is equivalent to using the variable @var{droptol}.\n\ \n\ @item milu\n\ A logical variable flagging whether to use the modified incomplete\n\ LU@tie{} factorization. In the case that @code{milu} is true, the dropped\n\ values are subtracted from the diagonal of the matrix @var{U} of the\n\ factorization. The default is @code{false}.\n\ \n\ @item udiag\n\ A logical variable that flags whether zero elements on the diagonal of\n\ @var{U} should be replaced with @var{droptol} to attempt to avoid singular\n\ factors. The default is @code{false}.\n\ \n\ @item thresh\n\ Defines the pivot threshold in the interval [0,1]. Values outside that\n\ range are ignored.\n\ @end table\n\ \n\ All other fields in @var{opts} are ignored. The outputs from @code{luinc}\n\ are the same as for @code{lu}.\n\ \n\ Given the string argument 'vector', @code{luinc} returns the values of\n\ @var{p} @var{q} as vector values.\n\ @seealso{sparse, lu}\n\ @end deftypefn")

Function Documentation

DEFUN_DLD ( luinc  ,
args  ,
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