ccolamdmex.c

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/* ========================================================================== */
/* === ccolamd mexFunction ================================================== */
/* ========================================================================== */
 
/* ----------------------------------------------------------------------------
 * CCOLAMD, Copyright (C), Univ. of Florida.  Authors: Timothy A. Davis,
 * Sivasankaran Rajamanickam, and Stefan Larimore
 * -------------------------------------------------------------------------- */
 
/* 
 * Usage:
 *      p = ccolamd (A) ;
 *      [p stats] = ccolamd (A, knobs, cmember) ;
 *
 * See ccolamd.m for a description.
 */
 
/* ========================================================================== */
/* === Include files ======================================================== */
/* ========================================================================== */
 
#include "ccolamd.h"
#include "mex.h"
#include "matrix.h"
#include <stdlib.h>
#include <string.h>
#define Long SuiteSparse_long
 
/* ========================================================================== */
/* === ccolamd mexFunction ================================================== */
/* ========================================================================== */
 
void mexFunction
(
    /* === Parameters ======================================================= */
 
    int nargout,
    mxArray *pargout [ ],
    int nargin,
    const mxArray *pargin [ ]
)
{
    /* === Local variables ================================================== */
 
    Long *A ;                   /* ccolamd's copy of the matrix and workspace */
    Long *cmember ;             /* ccolamd's copy of the constraint set */
    double *in_cmember ;        /* input constraint set */
    Long *p ;                   /* ccolamd's copy of the column pointers */
    Long Alen ;                 /* size of A */
    Long cslen ;                /* size of CS  */
    Long n_col ;                /* number of columns of A */
    Long n_row ;                /* number of rows of A */
    Long nnz ;                  /* number of entries in A */
    Long full ;                 /* TRUE if input matrix full, FALSE if sparse */
    double knobs [CCOLAMD_KNOBS] ; /* ccolamd user-controllable parameters */
    double *out_perm ;          /* output permutation vector */
    double *out_stats ;         /* output stats vector */
    double *in_knobs ;          /* input knobs vector */
    Long i ;                    /* loop counter */
    mxArray *Ainput ;           /* input matrix handle */
    Long spumoni ;              /* verbosity variable */
    Long stats [CCOLAMD_STATS] ;/* stats for ccolamd */
 
    /* === Check inputs ===================================================== */
 
    if (nargin < 1 || nargin > 3 || nargout < 0 || nargout > 2)
    {
        mexErrMsgTxt ("Usage: [p stats] = ccolamd (A, knobs, cmember)") ;
    }
 
    /* === Get cmember ====================================================== */
 
    cmember = NULL ;
    cslen = 0 ;
    if (nargin > 2)
    {
        in_cmember = mxGetPr (pargin [2]) ;
        cslen = mxGetNumberOfElements (pargin [2]) ;
        if (cslen != 0)
        {
            cmember = (Long *) mxCalloc (cslen, sizeof (Long)) ;
            for (i = 0 ; i < cslen ; i++)
            {
                /* convert cmember from 1-based to 0-based */
                cmember[i] = ((Long) in_cmember [i] - 1) ;
            }
        }
    }
 
    /* === Get knobs ======================================================== */
 
    ccolamd_l_set_defaults (knobs) ;
    spumoni = 0 ;
 
    /* check for user-passed knobs */
    if (nargin > 1)
    {
        in_knobs = mxGetPr (pargin [1]) ;
        i = mxGetNumberOfElements (pargin [1]) ;
        if (i > 0) knobs [CCOLAMD_LU] = (in_knobs [0] != 0) ;
        if (i > 1) knobs [CCOLAMD_DENSE_ROW]  = in_knobs [1] ;
        if (i > 2) knobs [CCOLAMD_DENSE_COL]  = in_knobs [2] ;
        if (i > 3) knobs [CCOLAMD_AGGRESSIVE] = (in_knobs [3] != 0) ;
        if (i > 4) spumoni = (in_knobs [4] != 0) ;
    }
 
    /* print knob settings if spumoni is set */
    if (spumoni)
    {
        mexPrintf ("\nccolamd version %d.%d, %s:\nknobs(1): %g, order for %s\n",
            CCOLAMD_MAIN_VERSION, CCOLAMD_SUB_VERSION, CCOLAMD_DATE,
            in_knobs [0],
            (knobs [CCOLAMD_LU] != 0) ? "lu(A)" : "chol(A'*A)") ;
        if (knobs [CCOLAMD_DENSE_ROW] >= 0)
        {
            mexPrintf ("knobs(2): %g, rows with > max(16,%g*sqrt(size(A,2)))"
                " entries removed\n", in_knobs [1], knobs [CCOLAMD_DENSE_ROW]) ;
        }
        else
        {
            mexPrintf ("knobs(2): %g, no dense rows removed\n", in_knobs [1]) ;
        }
        if (knobs [CCOLAMD_DENSE_COL] >= 0)
        {
            mexPrintf ("knobs(3): %g, cols with > max(16,%g*sqrt(min(size(A)))"
                " entries removed\n", in_knobs [2], knobs [CCOLAMD_DENSE_COL]) ;
        }
        else
        {
            mexPrintf ("knobs(3): no dense columns removed\n", in_knobs [2]) ;
        }
        mexPrintf ("knobs(4): %g, aggressive absorption: %s\n",
            in_knobs [3], (knobs [CCOLAMD_AGGRESSIVE] != 0) ? "yes" : "no") ;
        mexPrintf ("knobs(5): %g, statistics and knobs printed\n",
            in_knobs [4]) ;
    }
 
    /* === If A is full, convert to a sparse matrix ========================= */
 
    Ainput = (mxArray *) pargin [0] ;
    if (mxGetNumberOfDimensions (Ainput) != 2)
    {
        mexErrMsgTxt ("ccolamd: input matrix must be 2-dimensional") ;
    }
    full = !mxIsSparse (Ainput) ;
    if (full)
    {
        mexCallMATLAB (1, &Ainput, 1, (mxArray **) pargin, "sparse") ;
    }
 
    /* === Allocate workspace for ccolamd =================================== */
 
    /* get size of matrix */
    n_row = mxGetM (Ainput) ;
    n_col = mxGetN (Ainput) ;
 
    /* get column pointer vector */
    p = (Long *) mxCalloc (n_col+1, sizeof (Long)) ;
    (void) memcpy (p, mxGetJc (Ainput), (n_col+1)*sizeof (Long)) ;
    nnz = p [n_col] ;
    Alen = (Long) ccolamd_l_recommended (nnz, n_row, n_col) ;
    if (Alen == 0)
    {
        mexErrMsgTxt ("ccolamd: problem too large") ;
    }
 
    /* === Copy input matrix into workspace ================================= */
 
    A = (Long *) mxCalloc (Alen, sizeof (Long)) ;
    (void) memcpy (A, mxGetIr (Ainput), nnz*sizeof (Long)) ;
 
    if (full)
    {
        mxDestroyArray (Ainput) ;
    }
 
    /* Check constraint set size */
    if (cmember != NULL && cslen != n_col)
    {
        mexErrMsgTxt ("ccolamd: cmember must be of length equal to #cols of A");
    }
 
    /* === Order the columns (destroys A) =================================== */
 
    if (!ccolamd_l (n_row, n_col, Alen, A, p, knobs, stats, cmember))
    {
        ccolamd_l_report (stats) ;
        mexErrMsgTxt ("ccolamd error!") ;
    }
    mxFree (A) ;
    mxFree (cmember) ;
 
    /* === Return the permutation vector ==================================== */
 
    pargout [0] = mxCreateDoubleMatrix (1, n_col, mxREAL) ;
    out_perm = mxGetPr (pargout [0]) ;
    for (i = 0 ; i < n_col ; i++)
    {
        /* ccolamd is 0-based, but MATLAB expects this to be 1-based */
        out_perm [i] = p [i] + 1 ;
    }
    mxFree (p) ;
 
    /* === Return the stats vector ========================================== */
 
    /* print stats if spumoni is set */
    if (spumoni)
    {
        ccolamd_l_report (stats) ;
    }
 
    if (nargout == 2)
    {
        pargout [1] = mxCreateDoubleMatrix (1, CCOLAMD_STATS, mxREAL) ;
        out_stats = mxGetPr (pargout [1]) ;
        for (i = 0 ; i < CCOLAMD_STATS ; i++)
        {
            out_stats [i] = stats [i] ;
        }
 
        /* fix stats (5) and (6), for 1-based information on jumbled matrix. */
        /* note that this correction doesn't occur if symamd returns FALSE */
        out_stats [CCOLAMD_INFO1] ++ ; 
        out_stats [CCOLAMD_INFO2] ++ ; 
    }
}