1 /* ========================================================================= */
2 /* === AMD_order =========================================================== */
3 /* ========================================================================= */
4
5 /* ------------------------------------------------------------------------- */
6 /* AMD, Copyright (c) Timothy A. Davis, */
7 /* Patrick R. Amestoy, and Iain S. Duff. See ../README.txt for License. */
8 /* email: davis at cise.ufl.edu CISE Department, Univ. of Florida. */
9 /* web: http://www.cise.ufl.edu/research/sparse/amd */
10 /* ------------------------------------------------------------------------- */
11
12 /* User-callable AMD minimum degree ordering routine. See amd.h for
13 * documentation.
14 */
15
16 #include "amd_internal.h"
17
18 /* ========================================================================= */
19 /* === AMD_order =========================================================== */
20 /* ========================================================================= */
21
AMD_order(Int n,const Int Ap[],const Int Ai[],Int P[],double Control[],double Info[])22 GLOBAL Int AMD_order
23 (
24 Int n,
25 const Int Ap [ ],
26 const Int Ai [ ],
27 Int P [ ],
28 double Control [ ],
29 double Info [ ]
30 )
31 {
32 Int *Len, *S, nz, i, *Pinv, info, status, *Rp, *Ri, *Cp, *Ci, ok ;
33 size_t nzaat, slen ;
34 double mem = 0 ;
35
36 #ifndef NDEBUG
37 AMD_debug_init ("amd") ;
38 #endif
39
40 /* clear the Info array, if it exists */
41 info = Info != (double *) NULL ;
42 if (info)
43 {
44 for (i = 0 ; i < AMD_INFO ; i++)
45 {
46 Info [i] = EMPTY ;
47 }
48 Info [AMD_N] = n ;
49 Info [AMD_STATUS] = AMD_OK ;
50 }
51
52 /* make sure inputs exist and n is >= 0 */
53 if (Ai == (Int *) NULL || Ap == (Int *) NULL || P == (Int *) NULL || n < 0)
54 {
55 if (info) Info [AMD_STATUS] = AMD_INVALID ;
56 return (AMD_INVALID) ; /* arguments are invalid */
57 }
58
59 if (n == 0)
60 {
61 return (AMD_OK) ; /* n is 0 so there's nothing to do */
62 }
63
64 nz = Ap [n] ;
65 if (info)
66 {
67 Info [AMD_NZ] = nz ;
68 }
69 if (nz < 0)
70 {
71 if (info) Info [AMD_STATUS] = AMD_INVALID ;
72 return (AMD_INVALID) ;
73 }
74
75 /* check if n or nz will cause size_t overflow */
76 if (((size_t) n) >= SIZE_T_MAX / sizeof (Int)
77 || ((size_t) nz) >= SIZE_T_MAX / sizeof (Int))
78 {
79 if (info) Info [AMD_STATUS] = AMD_OUT_OF_MEMORY ;
80 return (AMD_OUT_OF_MEMORY) ; /* problem too large */
81 }
82
83 /* check the input matrix: AMD_OK, AMD_INVALID, or AMD_OK_BUT_JUMBLED */
84 status = AMD_valid (n, n, Ap, Ai) ;
85
86 if (status == AMD_INVALID)
87 {
88 if (info) Info [AMD_STATUS] = AMD_INVALID ;
89 return (AMD_INVALID) ; /* matrix is invalid */
90 }
91
92 /* allocate two size-n integer workspaces */
93 Len = amd_malloc (n * sizeof (Int)) ;
94 Pinv = amd_malloc (n * sizeof (Int)) ;
95 mem += n ;
96 mem += n ;
97 if (!Len || !Pinv)
98 {
99 /* :: out of memory :: */
100 amd_free (Len) ;
101 amd_free (Pinv) ;
102 if (info) Info [AMD_STATUS] = AMD_OUT_OF_MEMORY ;
103 return (AMD_OUT_OF_MEMORY) ;
104 }
105
106 if (status == AMD_OK_BUT_JUMBLED)
107 {
108 /* sort the input matrix and remove duplicate entries */
109 AMD_DEBUG1 (("Matrix is jumbled\n")) ;
110 Rp = amd_malloc ((n+1) * sizeof (Int)) ;
111 Ri = amd_malloc (MAX (nz,1) * sizeof (Int)) ;
112 mem += (n+1) ;
113 mem += MAX (nz,1) ;
114 if (!Rp || !Ri)
115 {
116 /* :: out of memory :: */
117 amd_free (Rp) ;
118 amd_free (Ri) ;
119 amd_free (Len) ;
120 amd_free (Pinv) ;
121 if (info) Info [AMD_STATUS] = AMD_OUT_OF_MEMORY ;
122 return (AMD_OUT_OF_MEMORY) ;
123 }
124 /* use Len and Pinv as workspace to create R = A' */
125 AMD_preprocess (n, Ap, Ai, Rp, Ri, Len, Pinv) ;
126 Cp = Rp ;
127 Ci = Ri ;
128 }
129 else
130 {
131 /* order the input matrix as-is. No need to compute R = A' first */
132 Rp = NULL ;
133 Ri = NULL ;
134 Cp = (Int *) Ap ;
135 Ci = (Int *) Ai ;
136 }
137
138 /* --------------------------------------------------------------------- */
139 /* determine the symmetry and count off-diagonal nonzeros in A+A' */
140 /* --------------------------------------------------------------------- */
141
142 nzaat = AMD_aat (n, Cp, Ci, Len, P, Info) ;
143 AMD_DEBUG1 (("nzaat: %g\n", (double) nzaat)) ;
144 ASSERT ((MAX (nz-n, 0) <= nzaat) && (nzaat <= 2 * (size_t) nz)) ;
145
146 /* --------------------------------------------------------------------- */
147 /* allocate workspace for matrix, elbow room, and 6 size-n vectors */
148 /* --------------------------------------------------------------------- */
149
150 S = NULL ;
151 slen = nzaat ; /* space for matrix */
152 ok = ((slen + nzaat/5) >= slen) ; /* check for size_t overflow */
153 slen += nzaat/5 ; /* add elbow room */
154 for (i = 0 ; ok && i < 7 ; i++)
155 {
156 ok = ((slen + n) > slen) ; /* check for size_t overflow */
157 slen += n ; /* size-n elbow room, 6 size-n work */
158 }
159 mem += slen ;
160 ok = ok && (slen < SIZE_T_MAX / sizeof (Int)) ; /* check for overflow */
161 ok = ok && (slen < Int_MAX) ; /* S[i] for Int i must be OK */
162 if (ok)
163 {
164 S = amd_malloc (slen * sizeof (Int)) ;
165 }
166 AMD_DEBUG1 (("slen %g\n", (double) slen)) ;
167 if (!S)
168 {
169 /* :: out of memory :: (or problem too large) */
170 amd_free (Rp) ;
171 amd_free (Ri) ;
172 amd_free (Len) ;
173 amd_free (Pinv) ;
174 if (info) Info [AMD_STATUS] = AMD_OUT_OF_MEMORY ;
175 return (AMD_OUT_OF_MEMORY) ;
176 }
177 if (info)
178 {
179 /* memory usage, in bytes. */
180 Info [AMD_MEMORY] = mem * sizeof (Int) ;
181 }
182
183 /* --------------------------------------------------------------------- */
184 /* order the matrix */
185 /* --------------------------------------------------------------------- */
186
187 AMD_1 (n, Cp, Ci, P, Pinv, Len, slen, S, Control, Info) ;
188
189 /* --------------------------------------------------------------------- */
190 /* free the workspace */
191 /* --------------------------------------------------------------------- */
192
193 amd_free (Rp) ;
194 amd_free (Ri) ;
195 amd_free (Len) ;
196 amd_free (Pinv) ;
197 amd_free (S) ;
198 if (info) Info [AMD_STATUS] = status ;
199 return (status) ; /* successful ordering */
200 }
201