1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
//------------------------------------------------------------------------------
// LG_nself_edges: count the # of diagonal entries in a matrix
//------------------------------------------------------------------------------
// LAGraph, (c) 2019-2022 by The LAGraph Contributors, All Rights Reserved.
// SPDX-License-Identifier: BSD-2-Clause
//
// For additional details (including references to third party source code and
// other files) see the LICENSE file or contact permission@sei.cmu.edu. See
// Contributors.txt for a full list of contributors. Created, in part, with
// funding and support from the U.S. Government (see Acknowledgments.txt file).
// DM22-0790
// Contributed by Timothy A. Davis, Texas A&M University
//------------------------------------------------------------------------------
#define LG_FREE_ALL \
{ \
GrB_free (&M) ; \
GrB_free (&D) ; \
GrB_free (&d) ; \
}
#include "LG_internal.h"
int LG_nself_edges
(
// output:
int64_t *nself_edges, // # of entries
// input:
GrB_Matrix A, // matrix to count
char *msg // error message
)
{
//--------------------------------------------------------------------------
// extract the diagonal and count its entries
//--------------------------------------------------------------------------
GrB_Matrix D = NULL, M = NULL ;
GrB_Vector d = NULL ;
LG_ASSERT (nself_edges != NULL, GrB_NULL_POINTER) ;
(*nself_edges) = LAGRAPH_UNKNOWN ;
GrB_Index nrows, ncols ;
GRB_TRY (GrB_Matrix_nrows (&nrows, A)) ;
GRB_TRY (GrB_Matrix_ncols (&ncols, A)) ;
GrB_Index n = LAGRAPH_MIN (nrows, ncols) ;
// FUTURE: use a method that does not require atype
GrB_Type atype ;
char atype_name [LAGRAPH_MAX_NAME_LEN] ;
LG_TRY (LAGraph_Matrix_TypeName (atype_name, A, msg)) ;
LG_TRY (LAGraph_TypeFromName (&atype, atype_name, msg)) ;
#if LAGRAPH_SUITESPARSE
//----------------------------------------------------------------------
// SuiteSparse:GraphBLAS
//----------------------------------------------------------------------
GRB_TRY (GrB_Vector_new (&d, atype, n)) ;
GRB_TRY (GxB_Vector_diag (d, A, 0, NULL)) ;
GRB_TRY (GrB_Vector_nvals ((GrB_Index *) nself_edges, d)) ;
#else
//----------------------------------------------------------------------
// pure GrB version
//----------------------------------------------------------------------
GRB_TRY (GrB_Matrix_new (&M, GrB_BOOL, nrows, ncols)) ;
GRB_TRY (GrB_Matrix_new (&D, atype, nrows, ncols)) ;
for (int64_t i = 0 ; i < n ; i++)
{
// M (i,i) = true
GRB_TRY (GrB_Matrix_setElement (M, (bool) true, i, i)) ;
}
// D<M,struct> = A
GRB_TRY (GrB_assign (D, M, NULL, A, GrB_ALL, nrows, GrB_ALL, ncols,
GrB_DESC_S)) ;
GRB_TRY (GrB_Matrix_nvals ((GrB_Index *) nself_edges, D)) ;
#endif
LG_FREE_ALL ;
return (GrB_SUCCESS) ;
}