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
//------------------------------------------------------------------------------
// LAGraph_Matrix_Structure: return the structure of 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 and Scott Kolodziej, Texas A&M University
//------------------------------------------------------------------------------
// LAGraph_Matrix_Structure: return the structure of a matrix as a boolean
// matrix, where C(i,j)=true if the entry A(i,j) is present in the matrix A.
#define LG_FREE_ALL GrB_free (C) ;
#include "LG_internal.h"
int LAGraph_Matrix_Structure
(
// output:
GrB_Matrix *C, // a boolean matrix with same structure of A, with C(i,j)
// set to true if A(i,j) appears in the sparsity structure
// of A.
// input:
GrB_Matrix A,
char *msg
)
{
//--------------------------------------------------------------------------
// check inputs
//--------------------------------------------------------------------------
LG_CLEAR_MSG ;
GrB_Index nrows, ncols ;
LG_ASSERT_MSG (C != NULL, GrB_NULL_POINTER, "&C != NULL") ;
LG_ASSERT (A != NULL, GrB_NULL_POINTER) ;
(*C) = NULL ;
//--------------------------------------------------------------------------
// get the size of A
//--------------------------------------------------------------------------
GRB_TRY (GrB_Matrix_nrows (&nrows, A)) ;
GRB_TRY (GrB_Matrix_ncols (&ncols, A)) ;
//--------------------------------------------------------------------------
// C<s(A)> = true
//--------------------------------------------------------------------------
GRB_TRY (GrB_Matrix_new (C, GrB_BOOL, nrows, ncols)) ;
GRB_TRY (GrB_assign (*C, A, NULL, (bool) true,
GrB_ALL, nrows, GrB_ALL, ncols, GrB_DESC_S)) ;
return (GrB_SUCCESS) ;
}