Function _ufunc_setup_flags

numpy/core/src/umath/ufunc_object.c:384–405

* Set per-operand flags according to desired input or output flags. * op_flags[i] for i in input (as determined by ufunc->nin) will be * merged with op_in_flags, perhaps overriding per-operand flags set * in previous stages. * op_flags[i] for i in output will be set to op_out_flags only if previously * unset. * The input flag behavior preserves backward compatibility, while the * output fla

 * output flag behaviour is the "correct" one for maximum flexibility.
 */
NPY_NO_EXPORT void
_ufunc_setup_flags(PyUFuncObject *ufunc, npy_uint32 op_in_flags,
                   npy_uint32 op_out_flags, npy_uint32 *op_flags)
{
    int nin = ufunc->nin;
    int nout = ufunc->nout;
    int nop = nin + nout, i;
    /* Set up the flags */
    for (i = 0; i < nin; ++i) {
        op_flags[i] = ufunc->op_flags[i] | op_in_flags;
        /*
         * If READWRITE flag has been set for this operand,
         * then clear default READONLY flag
         */
        if (op_flags[i] & (NPY_ITER_READWRITE | NPY_ITER_WRITEONLY)) {
            op_flags[i] &= ~NPY_ITER_READONLY;
        }
    }
    for (i = nin; i < nop; ++i) {
        op_flags[i] = ufunc->op_flags[i] ? ufunc->op_flags[i] : op_out_flags;
    }
}

/*
 * This function analyzes the input arguments