Function GB_binop_pattern

deps/GraphBLAS/Source/GB_binop_pattern.c:17–56

#include "GB_binop.h"

void GB_binop_pattern
(
    // outputs:
    bool *A_is_pattern,     // true if A is pattern-only, because of the op
    bool *B_is_pattern,     // true if B is pattern-only, because of the op
    // inputs:
    const bool flipxy,      // if true,  z = op (b,a) will be computed
                            // if false, z = op (a,b) will be computed
    const GB_Opcode opcode  // opcode of binary op
)
{

    //--------------------------------------------------------------------------
    // determine A_is_pattern and B_is_pattern
    //--------------------------------------------------------------------------

    bool op_is_positional = GB_OPCODE_IS_POSITIONAL (opcode) ;
    bool op_is_first  = (opcode == GB_FIRST_binop_code) ;
    bool op_is_second = (opcode == GB_SECOND_binop_code) ;
    bool op_is_pair   = (opcode == GB_PAIR_binop_code) ;

    if (op_is_positional || op_is_pair)
    { 
        // mult (x,y) does not depend on the values of x or y
        (*A_is_pattern) = true ;
        (*B_is_pattern) = true ;
    }
    else if (flipxy)
    { 
        // z = mult (b,a) will be computed
        (*A_is_pattern) = op_is_first  ;
        (*B_is_pattern) = op_is_second ;
    }
    else
    { 
        // z = mult (a,b) will be computed
        (*A_is_pattern) = op_is_second ;
        (*B_is_pattern) = op_is_first  ;
    }
}