Line data    Source code

       1             : //------------------------------------------------------------------------------
       2             : // LG_nself_edges: count the # of diagonal entries in a matrix
       3             : //------------------------------------------------------------------------------
       4             : 
       5             : // LAGraph, (c) 2019-2022 by The LAGraph Contributors, All Rights Reserved.
       6             : // SPDX-License-Identifier: BSD-2-Clause
       7             : //
       8             : // For additional details (including references to third party source code and
       9             : // other files) see the LICENSE file or contact permission@sei.cmu.edu. See
      10             : // Contributors.txt for a full list of contributors. Created, in part, with
      11             : // funding and support from the U.S. Government (see Acknowledgments.txt file).
      12             : // DM22-0790
      13             : 
      14             : // Contributed by Timothy A. Davis, Texas A&M University
      15             : 
      16             : //------------------------------------------------------------------------------
      17             : 
      18             : #define LG_FREE_ALL         \
      19             : {                           \
      20             :     GrB_free (&M) ;         \
      21             :     GrB_free (&D) ;         \
      22             :     GrB_free (&d) ;         \
      23             : }
      24             : 
      25             : #include "LG_internal.h"
      26             : 
      27         941 : int LG_nself_edges
      28             : (
      29             :     // output:
      30             :     int64_t *nself_edges,         // # of entries
      31             :     // input:
      32             :     GrB_Matrix A,           // matrix to count
      33             :     char *msg               // error message
      34             : )
      35             : {
      36             : 
      37             :     //--------------------------------------------------------------------------
      38             :     // extract the diagonal and count its entries
      39             :     //--------------------------------------------------------------------------
      40             : 
      41         941 :     GrB_Matrix D = NULL, M = NULL ;
      42         941 :     GrB_Vector d = NULL ;
      43         941 :     LG_ASSERT (nself_edges != NULL, GrB_NULL_POINTER) ;
      44         941 :     (*nself_edges) = LAGRAPH_UNKNOWN ;
      45             : 
      46             :     GrB_Index nrows, ncols ;
      47         941 :     GRB_TRY (GrB_Matrix_nrows (&nrows, A)) ;
      48         941 :     GRB_TRY (GrB_Matrix_ncols (&ncols, A)) ;
      49         941 :     GrB_Index n = LAGRAPH_MIN (nrows, ncols) ;
      50             : 
      51             :     // FUTURE: use a method that does not require atype
      52             : 
      53             :     GrB_Type atype ;
      54             :     char atype_name [LAGRAPH_MAX_NAME_LEN] ;
      55         941 :     LG_TRY (LAGraph_Matrix_TypeName (atype_name, A, msg)) ;
      56         941 :     LG_TRY (LAGraph_TypeFromName (&atype, atype_name, msg)) ;
      57             : 
      58             :     #if LAGRAPH_SUITESPARSE
      59             : 
      60             :         //----------------------------------------------------------------------
      61             :         // SuiteSparse:GraphBLAS v5.0.2: use GxB_Vector_diag
      62             :         //----------------------------------------------------------------------
      63             : 
      64         941 :         GRB_TRY (GrB_Vector_new (&d, atype, n)) ;
      65         809 :         GRB_TRY (GxB_Vector_diag (d, A, 0, NULL)) ;
      66         316 :         GRB_TRY (GrB_Vector_nvals ((GrB_Index *) nself_edges, d)) ;
      67             : 
      68             :     #else
      69             : 
      70             :         //----------------------------------------------------------------------
      71             :         // pure GrB version with no GxB extensions
      72             :         //----------------------------------------------------------------------
      73             : 
      74             :         GRB_TRY (GrB_Matrix_new (&M, GrB_BOOL, nrows, ncols)) ;
      75             :         GRB_TRY (GrB_Matrix_new (&D, atype, nrows, ncols)) ;
      76             :         for (int64_t i = 0 ; i < n ; i++)
      77             :         {
      78             :             // M (i,i) = true
      79             :             GRB_TRY (GrB_Matrix_setElement (M, (bool) true, i, i)) ;
      80             :         }
      81             : 
      82             :         // D<M,struct> = A
      83             :         GRB_TRY (GrB_assign (D, M, NULL, A, GrB_ALL, nrows, GrB_ALL, ncols,
      84             :             GrB_DESC_S)) ;
      85             :         GRB_TRY (GrB_Matrix_nvals ((GrB_Index *) nself_edges, D)) ;
      86             : 
      87             :     #endif
      88             : 
      89         316 :     LG_FREE_ALL ;
      90         316 :     return (GrB_SUCCESS) ;
      91             : }