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/* ========================================================================= */
/* === AMD_order =========================================================== */
/* ========================================================================= */
/* ------------------------------------------------------------------------- */
/* AMD, Copyright (c) Timothy A. Davis, */
/* Patrick R. Amestoy, and Iain S. Duff. See ../README.txt for License. */
/* email: davis at cise.ufl.edu CISE Department, Univ. of Florida. */
/* web: http://www.cise.ufl.edu/research/sparse/amd */
/* ------------------------------------------------------------------------- */
/* User-callable AMD minimum degree ordering routine. See amd.h for
* documentation.
*/
#include "amd_internal.h"
/* ========================================================================= */
/* === AMD_order =========================================================== */
/* ========================================================================= */
GLOBAL Int AMD_order
(
Int n,
const Int Ap [ ],
const Int Ai [ ],
Int P [ ],
double Control [ ],
double Info [ ]
)
{
Int *Len, *S, nz, i, *Pinv, info, status, *Rp, *Ri, *Cp, *Ci, ok ;
size_t nzaat, slen ;
double mem = 0 ;
#ifndef NDEBUG
AMD_debug_init ("amd") ;
#endif
/* clear the Info array, if it exists */
info = Info != (double *) NULL ;
if (info)
{
for (i = 0 ; i < AMD_INFO ; i++)
{
Info [i] = EMPTY ;
}
Info [AMD_N] = n ;
Info [AMD_STATUS] = AMD_OK ;
}
/* make sure inputs exist and n is >= 0 */
if (Ai == (Int *) NULL || Ap == (Int *) NULL || P == (Int *) NULL || n < 0)
{
if (info) Info [AMD_STATUS] = AMD_INVALID ;
return (AMD_INVALID) ; /* arguments are invalid */
}
if (n == 0)
{
return (AMD_OK) ; /* n is 0 so there's nothing to do */
}
nz = Ap [n] ;
if (info)
{
Info [AMD_NZ] = nz ;
}
if (nz < 0)
{
if (info) Info [AMD_STATUS] = AMD_INVALID ;
return (AMD_INVALID) ;
}
/* check if n or nz will cause size_t overflow */
if (((size_t) n) >= SIZE_T_MAX / sizeof (Int)
|| ((size_t) nz) >= SIZE_T_MAX / sizeof (Int))
{
if (info) Info [AMD_STATUS] = AMD_OUT_OF_MEMORY ;
return (AMD_OUT_OF_MEMORY) ; /* problem too large */
}
/* check the input matrix: AMD_OK, AMD_INVALID, or AMD_OK_BUT_JUMBLED */
status = AMD_valid (n, n, Ap, Ai) ;
if (status == AMD_INVALID)
{
if (info) Info [AMD_STATUS] = AMD_INVALID ;
return (AMD_INVALID) ; /* matrix is invalid */
}
/* allocate two size-n integer workspaces */
Len = amd_malloc (n * sizeof (Int)) ;
Pinv = amd_malloc (n * sizeof (Int)) ;
mem += n ;
mem += n ;
if (!Len || !Pinv)
{
/* :: out of memory :: */
amd_free (Len) ;
amd_free (Pinv) ;
if (info) Info [AMD_STATUS] = AMD_OUT_OF_MEMORY ;
return (AMD_OUT_OF_MEMORY) ;
}
if (status == AMD_OK_BUT_JUMBLED)
{
/* sort the input matrix and remove duplicate entries */
AMD_DEBUG1 (("Matrix is jumbled\n")) ;
Rp = amd_malloc ((n+1) * sizeof (Int)) ;
Ri = amd_malloc (MAX (nz,1) * sizeof (Int)) ;
mem += (n+1) ;
mem += MAX (nz,1) ;
if (!Rp || !Ri)
{
/* :: out of memory :: */
amd_free (Rp) ;
amd_free (Ri) ;
amd_free (Len) ;
amd_free (Pinv) ;
if (info) Info [AMD_STATUS] = AMD_OUT_OF_MEMORY ;
return (AMD_OUT_OF_MEMORY) ;
}
/* use Len and Pinv as workspace to create R = A' */
AMD_preprocess (n, Ap, Ai, Rp, Ri, Len, Pinv) ;
Cp = Rp ;
Ci = Ri ;
}
else
{
/* order the input matrix as-is. No need to compute R = A' first */
Rp = NULL ;
Ri = NULL ;
Cp = (Int *) Ap ;
Ci = (Int *) Ai ;
}
/* --------------------------------------------------------------------- */
/* determine the symmetry and count off-diagonal nonzeros in A+A' */
/* --------------------------------------------------------------------- */
nzaat = AMD_aat (n, Cp, Ci, Len, P, Info) ;
AMD_DEBUG1 (("nzaat: %g\n", (double) nzaat)) ;
ASSERT ((MAX (nz-n, 0) <= nzaat) && (nzaat <= 2 * (size_t) nz)) ;
/* --------------------------------------------------------------------- */
/* allocate workspace for matrix, elbow room, and 6 size-n vectors */
/* --------------------------------------------------------------------- */
S = NULL ;
slen = nzaat ; /* space for matrix */
ok = ((slen + nzaat/5) >= slen) ; /* check for size_t overflow */
slen += nzaat/5 ; /* add elbow room */
for (i = 0 ; ok && i < 7 ; i++)
{
ok = ((slen + n) > slen) ; /* check for size_t overflow */
slen += n ; /* size-n elbow room, 6 size-n work */
}
mem += slen ;
ok = ok && (slen < SIZE_T_MAX / sizeof (Int)) ; /* check for overflow */
ok = ok && (slen < Int_MAX) ; /* S[i] for Int i must be OK */
if (ok)
{
S = amd_malloc (slen * sizeof (Int)) ;
}
AMD_DEBUG1 (("slen %g\n", (double) slen)) ;
if (!S)
{
/* :: out of memory :: (or problem too large) */
amd_free (Rp) ;
amd_free (Ri) ;
amd_free (Len) ;
amd_free (Pinv) ;
if (info) Info [AMD_STATUS] = AMD_OUT_OF_MEMORY ;
return (AMD_OUT_OF_MEMORY) ;
}
if (info)
{
/* memory usage, in bytes. */
Info [AMD_MEMORY] = mem * sizeof (Int) ;
}
/* --------------------------------------------------------------------- */
/* order the matrix */
/* --------------------------------------------------------------------- */
AMD_1 (n, Cp, Ci, P, Pinv, Len, slen, S, Control, Info) ;
/* --------------------------------------------------------------------- */
/* free the workspace */
/* --------------------------------------------------------------------- */
amd_free (Rp) ;
amd_free (Ri) ;
amd_free (Len) ;
amd_free (Pinv) ;
amd_free (S) ;
if (info) Info [AMD_STATUS] = status ;
return (status) ; /* successful ordering */
}
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