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
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
|
//------------------------------------------------------------------------------
// gbvdiag: extract a diaogonal of a matrix, as a vector
//------------------------------------------------------------------------------
// SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2022, All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
//------------------------------------------------------------------------------
// Usage:
// v = gbvdiag (A, k, desc)
#include "gb_interface.h"
#define USAGE "usage: v = gbvdiag (A, k, desc)"
void mexFunction
(
int nargout,
mxArray *pargout [ ],
int nargin,
const mxArray *pargin [ ]
)
{
//--------------------------------------------------------------------------
// check inputs
//--------------------------------------------------------------------------
gb_usage (nargin >= 1 && nargin <= 3 && nargout <= 2, USAGE) ;
//--------------------------------------------------------------------------
// get the descriptor
//--------------------------------------------------------------------------
base_enum_t base ;
kind_enum_t kind ;
GxB_Format_Value fmt ;
int sparsity ;
GrB_Descriptor desc = NULL ;
desc = gb_mxarray_to_descriptor (pargin [nargin-1], &kind, &fmt,
&sparsity, &base) ;
// if present, remove the descriptor from consideration
if (desc != NULL) nargin-- ;
//--------------------------------------------------------------------------
// get the inputs
//--------------------------------------------------------------------------
GrB_Matrix V = NULL ;
GrB_Matrix A = gb_get_shallow (pargin [0]) ;
int64_t k = 0 ;
if (nargin > 1)
{
CHECK_ERROR (!gb_mxarray_is_scalar (pargin [1]), "k must be a scalar") ;
double x = mxGetScalar (pargin [1]) ;
k = (int64_t) x ;
CHECK_ERROR ((double) k != x, "k must be an integer scalar") ;
}
//--------------------------------------------------------------------------
// construct V
//--------------------------------------------------------------------------
GrB_Type vtype = NULL ;
int64_t n, nrows, ncols ;
OK (GxB_Matrix_type (&vtype, A)) ;
OK (GrB_Matrix_nrows (&nrows, A)) ;
OK (GrB_Matrix_ncols (&ncols, A)) ;
if (k >= ncols || k <= -nrows)
{
// output vector V must have zero length
n = 0 ;
}
else if (k >= 0)
{
// if k is in range 0 to n-1, V must have length min (m,n-k)
n = GB_IMIN (nrows, ncols - k) ;
}
else
{
// if k is in range -1 to -m+1, V must have length min (m+k,n)
n = GB_IMIN (nrows + k, ncols) ;
}
V = gb_new (vtype, n, 1, GxB_BY_COL, 0) ;
//--------------------------------------------------------------------------
// compute v = diag (A, k)
//--------------------------------------------------------------------------
OK1 (V, GxB_Vector_diag ((GrB_Vector) V, A, k, desc)) ;
//--------------------------------------------------------------------------
// free shallow copies
//--------------------------------------------------------------------------
OK (GrB_Matrix_free (&A)) ;
OK (GrB_Descriptor_free (&desc)) ;
//--------------------------------------------------------------------------
// export the output matrix V
//--------------------------------------------------------------------------
pargout [0] = gb_export (&V, kind) ;
pargout [1] = mxCreateDoubleScalar (kind) ;
GB_WRAPUP ;
}
|
