Function PyUFunc_GetDefaultIdentity

numpy/core/src/umath/ufunc_object.c:2123–2157

* Returns a new reference to the ufunc identity. Note that this identity * is only a default identity value stored on the ufunc, since the invidiual * ufunc loop (ArrayMethod) is queried for the actual identity. * * TODO: store a reference in the ufunc object itself, rather than * constructing one each time */

 *       constructing one each time
 */
NPY_NO_EXPORT PyObject *
PyUFunc_GetDefaultIdentity(PyUFuncObject *ufunc, npy_bool *reorderable)
{
    switch(ufunc->identity) {
    case PyUFunc_One:
        *reorderable = 1;
        return PyLong_FromLong(1);

    case PyUFunc_Zero:
        *reorderable = 1;
        return PyLong_FromLong(0);

    case PyUFunc_MinusOne:
        *reorderable = 1;
        return PyLong_FromLong(-1);

    case PyUFunc_ReorderableNone:
        *reorderable = 1;
        Py_RETURN_NONE;

    case PyUFunc_None:
        *reorderable = 0;
        Py_RETURN_NONE;

    case PyUFunc_IdentityValue:
        *reorderable = 1;
        Py_INCREF(ufunc->identity_value);
        return ufunc->identity_value;

    default:
        PyErr_Format(PyExc_ValueError,
                "ufunc %s has an invalid identity", ufunc_get_name_cstr(ufunc));
        return NULL;
    }
}

/*
 * Copy over parts of the ufunc structure that may need to be