//------------------------------------------------------------------------------
// GB_AxB_saxpy3_coarseGus_M_phase1: symbolic coarse Gustavson, with M
//------------------------------------------------------------------------------

// SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2023, All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

//------------------------------------------------------------------------------

{
    // Initially, Hf [...] < mark for all of Hf.

    // Hf [i] < mark    : M(i,j)=0, C(i,j) is ignored.
    // Hf [i] == mark   : M(i,j)=1, and C(i,j) not yet seen.
    // Hf [i] == mark+1 : M(i,j)=1, and C(i,j) has been seen.

    for (int64_t kk = kfirst ; kk <= klast ; kk++)
    {
        GB_GET_B_j ;            // get B(:,j)
        Cp [kk] = 0 ;

        //----------------------------------------------------------------------
        // special case when B(:,j) is empty
        //----------------------------------------------------------------------

        #if ( GB_B_IS_SPARSE || GB_B_IS_HYPER )
        if (bjnz == 0) continue ;
        #endif

        //----------------------------------------------------------------------
        // get M(:,j) and scatter it into the Hf workspace
        //----------------------------------------------------------------------

        GB_GET_M_j ;                                // get M(:,j)
        if (mjnz == 0) continue ;
        GB_GET_M_j_RANGE (64) ;
        mark += 2 ;
        const int64_t f0 = mark ;
        const int64_t f1 = mark+1 ;
        GB_SCATTER_M_j (pM_start, pM_end, f0) ;     // scatter M(:,j)

        //----------------------------------------------------------------------
        // count nnz in C(:,j)
        //----------------------------------------------------------------------

        int64_t cjnz = 0 ;
        for ( ; pB < pB_end ; pB++)     // scan B(:,j)
        { 
            GB_GET_B_kj_INDEX ;         // get k of B(k,j)
            GB_GET_A_k ;                // get A(:,k)
            if (aknz == 0) continue ;
            #define GB_IKJ                                          \
            {                                                       \
                if (Hf [i] == f0)       /* if true, M(i,j) is 1 */  \
                {                                                   \
                    Hf [i] = f1 ;       /* flag C(i,j) as seen */   \
                    cjnz++ ;            /* C(i,j) is new */         \
                }                                                   \
            }
            GB_SCAN_M_j_OR_A_k (((GB_A_IS_SPARSE || GB_A_IS_HYPER) && 
                !A_jumbled)) ;
            #undef GB_IKJ
        }
        Cp [kk] = cjnz ;                // count the entries in C(:,j)
    }
}

