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
|
//------------------------------------------------------------------------------
// GB_convert_sparse_to_bitmap_test: test conversion of hyper/sparse to bitmap
//------------------------------------------------------------------------------
// SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2022, All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
//------------------------------------------------------------------------------
// Returns true if a sparse or hypersparse matrix should be converted to bitmap
// (or full if all entries are present, but in that case, this function is not
// called). Returns false if the matrix should stay hypersparse/sparse.
// See GB_convert_bitmap_to_sparse_test for a description of this rule.
// These default rules may change in future releases of SuiteSparse:GraphBLAS.
// This rule is not used if all entries are present. In that case, the matrix
// becomes full, not bitmap, assuming the full format permitted by the sparsity
// control setting of the matrix.
#include "GB.h"
bool GB_convert_sparse_to_bitmap_test // test for hyper/sparse to bitmap
(
float bitmap_switch, // A->bitmap_switch
int64_t anz, // # of entries in A = GB_nnz (A)
int64_t vlen, // A->vlen
int64_t vdim // A->vdim
)
{
// current number of entries in the matrix or vector
float nnz = (float) anz ;
// maximum number of entries in the matrix or vector
float nnz_dense = ((float) vlen) * ((float) vdim) ;
// A should switch to bitmap if the following condition is true:
return (nnz > bitmap_switch * nnz_dense && nnz_dense < (float) GB_NMAX) ;
}
|
