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//------------------------------------------------------------------------------
// GraphBLAS/CUDA/GB_cuda_reduce_to_scalar_branch: decide to use GPU for reduce
//------------------------------------------------------------------------------
// SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2025, All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
//------------------------------------------------------------------------------
// Decide branch direction for GPU use for the reduction to scalar
#include "GB_cuda_reduce.hpp"
bool GB_cuda_reduce_to_scalar_branch // return true to use the GPU
(
const GrB_Monoid monoid, // monoid to do the reduction
const GrB_Matrix A // input matrix
)
{
if (!GB_cuda_type_branch (A->type) ||
!GB_cuda_type_branch (monoid->op->ztype))
{
// one or more types are not yet supported on the GPU
return (false) ;
}
if (monoid->op->opcode == GB_ANY_binop_code)
{
// the ANY monoid takes O(1) time; do it on the CPU:
return (false) ;
}
if (A->iso)
{
// A iso takes O(log(nvals(A))) time; do it on the CPU:
return (false) ;
}
// see if there is enough work to do on the GPU
double work = GB_nnz_held (A) ;
int ngpus_to_use = GB_ngpus_to_use (work) ;
GBURBLE (" work:%g gpus:%d ", work, ngpus_to_use) ;
if (ngpus_to_use > 0)
{
// FIXME: gpu_id = GB_Context_gpu_id_get ( ) ;
// cudaSetDevice (gpu_id) ;
return (true) ;
}
else
{
return (false) ;
}
}
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