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/* ========================================================================== */
/* === CHOLMOD/MATLAB/nesdis mexFunction ==================================== */
/* ========================================================================== */
/* -----------------------------------------------------------------------------
* CHOLMOD/MATLAB Module. Copyright (C) 2005-2006, Timothy A. Davis
* http://www.suitesparse.com
* MATLAB(tm) is a Trademark of The MathWorks, Inc.
* METIS is Copyrighted by G. Karypis
* -------------------------------------------------------------------------- */
/* CHOLMOD's nested dissection, based on METIS_ComputeVertexSeparator, CAMD, and
* CCOLAMD.
*
* Usage:
*
* [p, cp, cmember] = nesdis (A) orders A, using tril(A)
* [p, cp, cmember] = nesdis (A,'sym') orders A, using tril(A)
* [p, cp, cmember] = nesdis (A,'row') orders A*A'
* [p, cp, cmember] = nesdis (A,'col') orders A'*A
*
* Nested dissection ordering. Returns a permutation p such that the Cholesky
* factorization of A(p,p), A(p,:)*A(p,:)', or A(:,p)'*A(:,p) is sparser than
* the unpermuted system. 'mode' defaults to 'sym'.
*
* An optional 3rd input argument:
*
* nesdis (A,mode,opts)
*
* specifies control parameters. opts(1) is the smallest subgraph that should
* not be partitioned (default is 200), opts(2) is 1 if connected components are
* to be split independently (default is 0). opts(3) controls when a separator
* is kept; it is kept if nsep < opts(3)*n, where nsep is the number of nodes in
* the separator and n is the number of nodes in the graph being cut (default is
* 1).
*
* opts(4) is 0 if the smallest subgraphs are not to be ordered. For the 'sym'
* case, or if mode is not present: 1 if to be ordered by CAMD, or 2 if to be
* ordered with CSYMAMD (default is 1). For the other cases: 0 for natural
* ordering, 1 if to be ordered by CCOLAMD.
*
* cp and cmember are optional. cmember(i)=c means that node i is in component
* c, where c is in the range of 1 to the number of components. length(cp) is
* the number of components found. cp is the separator tree; cp(c) is the
* parent of component c, or 0 if c is a root. There can be anywhere from
* 1 to n components, where n is the number of rows of A, A*A', or A'*A.
*
* Requires METIS and the CHOLMOD Partition Module.
*/
#include "cholmod_matlab.h"
void mexFunction
(
int nargout,
mxArray *pargout [ ],
int nargin,
const mxArray *pargin [ ]
)
{
#ifndef NPARTITION
double dummy = 0 ;
Long *Perm, *Cmember, *CParent ;
cholmod_sparse *A, Amatrix, *C, *S ;
cholmod_common Common, *cm ;
Long n, transpose, c, ncomp ;
char buf [LEN] ;
/* ---------------------------------------------------------------------- */
/* start CHOLMOD and set defaults */
/* ---------------------------------------------------------------------- */
cm = &Common ;
cholmod_l_start (cm) ;
sputil_config (SPUMONI, cm) ;
/* ---------------------------------------------------------------------- */
/* get inputs */
/* ---------------------------------------------------------------------- */
if (nargout > 3 || nargin < 1 || nargin > 3)
{
mexErrMsgTxt ("Usage: [p cp cmember] = nesdis (A, mode, opts)") ;
}
if (nargin > 2)
{
double *x = mxGetPr (pargin [2]) ;
n = mxGetNumberOfElements (pargin [2]) ;
if (n > 0) cm->method [0].nd_small = x [0] ;
if (n > 1) cm->method [0].nd_components = x [1] ;
if (n > 2) cm->method [0].nd_oksep = x [2] ;
if (n > 3) cm->method [0].nd_camd = x [3] ;
}
/* ---------------------------------------------------------------------- */
/* get input matrix A */
/* ---------------------------------------------------------------------- */
A = sputil_get_sparse_pattern (pargin [0], &Amatrix, &dummy, cm) ;
S = (A == &Amatrix) ? NULL : A ;
/* ---------------------------------------------------------------------- */
/* get A->stype, default is to use tril(A) */
/* ---------------------------------------------------------------------- */
A->stype = -1 ;
transpose = FALSE ;
if (nargin > 1)
{
buf [0] = '\0' ;
if (mxIsChar (pargin [1]))
{
mxGetString (pargin [1], buf, LEN) ;
}
c = buf [0] ;
if (tolower (c) == 'r')
{
/* unsymmetric case (A*A') if string starts with 'r' */
transpose = FALSE ;
A->stype = 0 ;
}
else if (tolower (c) == 'c')
{
/* unsymmetric case (A'*A) if string starts with 'c' */
transpose = TRUE ;
A->stype = 0 ;
}
else if (tolower (c) == 's')
{
/* symmetric case (A) if string starts with 's' */
transpose = FALSE ;
A->stype = -1 ;
}
else
{
mexErrMsgTxt ("nesdis: unrecognized mode") ;
}
}
if (A->stype && A->nrow != A->ncol)
{
mexErrMsgTxt ("nesdis: A must be square") ;
}
C = NULL ;
if (transpose)
{
/* C = A', and then order C*C' with cholmod_l_nested_dissection */
C = cholmod_l_transpose (A, 0, cm) ;
if (C == NULL)
{
mexErrMsgTxt ("nesdis failed") ;
}
A = C ;
}
n = A->nrow ;
/* ---------------------------------------------------------------------- */
/* get workspace */
/* ---------------------------------------------------------------------- */
CParent = cholmod_l_malloc (n, sizeof (Long), cm) ;
Cmember = cholmod_l_malloc (n, sizeof (Long), cm) ;
Perm = cholmod_l_malloc (n, sizeof (Long), cm) ;
/* ---------------------------------------------------------------------- */
/* order the matrix with CHOLMOD's nested dissection */
/* ---------------------------------------------------------------------- */
ncomp = cholmod_l_nested_dissection (A, NULL, 0, Perm, CParent, Cmember,cm);
if (ncomp < 0)
{
mexErrMsgTxt ("nesdis failed") ;
return ;
}
/* ---------------------------------------------------------------------- */
/* return Perm, CParent, and Cmember */
/* ---------------------------------------------------------------------- */
pargout [0] = sputil_put_int (Perm, n, 1) ;
if (nargout > 1)
{
pargout [1] = sputil_put_int (CParent, ncomp, 1) ;
}
if (nargout > 2)
{
pargout [2] = sputil_put_int (Cmember, n, 1) ;
}
/* ---------------------------------------------------------------------- */
/* free workspace */
/* ---------------------------------------------------------------------- */
cholmod_l_free (n, sizeof (Long), Perm, cm) ;
cholmod_l_free (n, sizeof (Long), CParent, cm) ;
cholmod_l_free (n, sizeof (Long), Cmember, cm) ;
cholmod_l_free_sparse (&C, cm) ;
cholmod_l_free_sparse (&S, cm) ;
cholmod_l_finish (cm) ;
cholmod_l_print_common (" ", cm) ;
/*
if (cm->malloc_count != 0) mexErrMsgTxt ("!") ;
*/
#else
mexErrMsgTxt ("METIS and the CHOLMOD Partition Module not installed\n") ;
#endif
}
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