1 /* ========================================================================= */
2 /* === AMD_valid =========================================================== */
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 /* Check if a column-form matrix is valid or not. The matrix A is
13 * n_row-by-n_col. The row indices of entries in column j are in
14 * Ai [Ap [j] ... Ap [j+1]-1]. Required conditions are:
15 *
16 * n_row >= 0
17 * n_col >= 0
18 * nz = Ap [n_col] >= 0 number of entries in the matrix
19 * Ap [0] == 0
20 * Ap [j] <= Ap [j+1] for all j in the range 0 to n_col.
21 * Ai [0 ... nz-1] must be in the range 0 to n_row-1.
22 *
23 * If any of the above conditions hold, AMD_INVALID is returned. If the
24 * following condition holds, AMD_OK_BUT_JUMBLED is returned (a warning,
25 * not an error):
26 *
27 * row indices in Ai [Ap [j] ... Ap [j+1]-1] are not sorted in ascending
28 * order, and/or duplicate entries exist.
29 *
30 * Otherwise, AMD_OK is returned.
31 *
32 * In v1.2 and earlier, this function returned TRUE if the matrix was valid
33 * (now returns AMD_OK), or FALSE otherwise (now returns AMD_INVALID or
34 * AMD_OK_BUT_JUMBLED).
35 */
36
37 #include "amd_internal.h"
38
AMD_valid(Int n_row,Int n_col,const Int Ap[],const Int Ai[])39 GLOBAL Int AMD_valid
40 (
41 /* inputs, not modified on output: */
42 Int n_row, /* A is n_row-by-n_col */
43 Int n_col,
44 const Int Ap [ ], /* column pointers of A, of size n_col+1 */
45 const Int Ai [ ] /* row indices of A, of size nz = Ap [n_col] */
46 )
47 {
48 Int nz, j, p1, p2, ilast, i, p, result = AMD_OK ;
49
50 if (n_row < 0 || n_col < 0 || Ap == NULL || Ai == NULL)
51 {
52 return (AMD_INVALID) ;
53 }
54 nz = Ap [n_col] ;
55 if (Ap [0] != 0 || nz < 0)
56 {
57 /* column pointers must start at Ap [0] = 0, and Ap [n] must be >= 0 */
58 AMD_DEBUG0 (("column 0 pointer bad or nz < 0\n")) ;
59 return (AMD_INVALID) ;
60 }
61 for (j = 0 ; j < n_col ; j++)
62 {
63 p1 = Ap [j] ;
64 p2 = Ap [j+1] ;
65 AMD_DEBUG2 (("\nColumn: "ID" p1: "ID" p2: "ID"\n", j, p1, p2)) ;
66 if (p1 > p2)
67 {
68 /* column pointers must be ascending */
69 AMD_DEBUG0 (("column "ID" pointer bad\n", j)) ;
70 return (AMD_INVALID) ;
71 }
72 ilast = EMPTY ;
73 for (p = p1 ; p < p2 ; p++)
74 {
75 i = Ai [p] ;
76 AMD_DEBUG3 (("row: "ID"\n", i)) ;
77 if (i < 0 || i >= n_row)
78 {
79 /* row index out of range */
80 AMD_DEBUG0 (("index out of range, col "ID" row "ID"\n", j, i));
81 return (AMD_INVALID) ;
82 }
83 if (i <= ilast)
84 {
85 /* row index unsorted, or duplicate entry present */
86 AMD_DEBUG1 (("index unsorted/dupl col "ID" row "ID"\n", j, i));
87 result = AMD_OK_BUT_JUMBLED ;
88 }
89 ilast = i ;
90 }
91 }
92 return (result) ;
93 }
94