1 //------------------------------------------------------------------------------ 2 // GB_AxB_saxpy3_coarseGus_notM_phase1: symbolic coarse Gustavson, with !M 3 //------------------------------------------------------------------------------ 4 5 // SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2021, All Rights Reserved. 6 // SPDX-License-Identifier: Apache-2.0 7 8 //------------------------------------------------------------------------------ 9 10 { 11 // Initially, Hf [...] < mark for all of Hf. 12 13 // Hf [i] < mark : M(i,j)=0, C(i,j) is not yet seen. 14 // Hf [i] == mark : M(i,j)=1, so C(i,j) is ignored. 15 // Hf [i] == mark+1 : M(i,j)=0, and C(i,j) has been seen. 16 17 for (int64_t kk = kfirst ; kk <= klast ; kk++) 18 { 19 GB_GET_B_j ; // get B(:,j) 20 Cp [kk] = 0 ; 21 22 //---------------------------------------------------------------------- 23 // special case when B(:,j) is empty 24 //---------------------------------------------------------------------- 25 26 #if ( GB_B_IS_SPARSE || GB_B_IS_HYPER ) 27 if (bjnz == 0) continue ; 28 #endif 29 30 //---------------------------------------------------------------------- 31 // get M(:,j) and scatter it into the Hf workspace 32 //---------------------------------------------------------------------- 33 34 GB_GET_M_j ; // get M(:,j) 35 mark += 2 ; 36 const int64_t f0 = mark ; 37 const int64_t f1 = mark+1 ; 38 GB_SCATTER_M_j (pM_start, pM_end, f0) ; // scatter M(:,j) 39 40 //---------------------------------------------------------------------- 41 // count nnz in C(:,j) 42 //---------------------------------------------------------------------- 43 44 int64_t cjnz = 0 ; 45 for ( ; pB < pB_end ; pB++) // scan B(:,j) 46 { 47 GB_GET_B_kj_INDEX ; // get k of B(k,j) 48 GB_GET_A_k ; // get A(:,k) 49 // scan A(:,k) 50 for (int64_t pA = pA_start ; pA < pA_end ; pA++) 51 { 52 GB_GET_A_ik_INDEX ; // get index i of A(i,k) 53 if (Hf [i] < f0) // if true, M(i,j) is 0 54 { 55 Hf [i] = f1 ; // flag C(i,j) as seen 56 cjnz++ ; // C(i,j) is a new entry 57 } 58 } 59 } 60 Cp [kk] = cjnz ; // count the entries in C(:,j) 61 } 62 } 63 64