//------------------------------------------------------------------------------ // GB_reduce_to_scalar_iso: reduce an iso matrix to a scalar //------------------------------------------------------------------------------ // SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2023, All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 //------------------------------------------------------------------------------ #include "GB_reduce.h" void GB_reduce_to_scalar_iso // s = reduce (A) where A is iso ( GB_void *restrict s, // output scalar of type reduce->op->ztype GrB_Monoid monoid, // monoid to use for the reduction GrB_Matrix A // matrix to reduce ) { //-------------------------------------------------------------------------- // check inputs //-------------------------------------------------------------------------- ASSERT (A->iso) ; ASSERT_MATRIX_OK (A, "A for reduce_to_scalar_iso", GB0) ; ASSERT_MONOID_OK (monoid, "monoid for reduce_to_scalar_iso", GB0) ; ASSERT (s != NULL) ; ASSERT (GB_ZOMBIES_OK (A)) ; ASSERT (GB_JUMBLED_OK (A)) ; ASSERT (!GB_PENDING (A)) ; //-------------------------------------------------------------------------- // get input matrix and the monoid //-------------------------------------------------------------------------- // A consists of n entries, all equal to Ax [0] uint64_t n = (uint64_t) (GB_nnz (A) - A->nzombies) ; ASSERT (n > 0) ; // get the monoid GxB_binary_function freduce = monoid->op->binop_function ; GrB_Type ztype = monoid->op->ztype ; size_t zsize = ztype->size ; GB_Type_code zcode = ztype->code ; // a = (ztype) Ax [0] GB_void a [GB_VLA(zsize)] ; GB_cast_scalar (a, zcode, A->x, A->type->code, zsize) ; //-------------------------------------------------------------------------- // reduce n entries, all equal to a, to the scalar s, in O(log(n)) time //-------------------------------------------------------------------------- GB_reduce_worker_iso (s, freduce, a, n, zsize) ; }