Python Cython 返回的内存视图始终被视为未初始化

类似于Cython Memoryview as return value，但除了破解生成的C代码外，我没有看到其他解决方案.

我使用的是Cython3.0，但结果看起来和<3一样.

下面是一个例子:

# cython: language_level=3, boundscheck=False, cdivision=True, wraparound=False, initializedcheck=False, nonecheck=False
cimport cython
from cython cimport floating
import numpy as np
cimport numpy as np

np.import_array()

def test_func():
    cdef np.ndarray[float, ndim=2] arr = np.zeros((5, 5), dtype=np.float32)
    cdef float[:, ::1] arr_view = arr
    _run(arr_view)

cdef void _run(floating[:, ::1] arr_view) noexcept nogil:
    cdef floating[:, :] tmp = _get_upper_left_corner(arr_view)

cdef inline floating[:, :] _get_upper_left_corner(floating[:, ::1] arr) noexcept nogil:
    return arr[:-1, :-1]

然后运行cython -a cython_test.pyx，它显示_get_upper_left_corner函数有包括GIL获取的Memory view初始化代码，_run函数有错误判断，因为_get_upper_left_corner函数可能返回错误(至少我是这么猜的):

+17: cdef inline floating[:, :] _get_upper_left_corner(floating[:, ::1] arr) noexcept nogil:

static CYTHON_INLINE __Pyx_memviewslice __pyx_fuse_0__pyx_f_11cython_test__get_upper_left_corner(__Pyx_memviewslice __pyx_v_arr) {
  __Pyx_memviewslice __pyx_r = { 0, 0, { 0 }, { 0 }, { 0 } };
/* … */
  /* function exit code */
  __pyx_L1_error:;
  #ifdef WITH_THREAD
  __pyx_gilstate_save = __Pyx_PyGILState_Ensure();
  #endif
  __PYX_XCLEAR_MEMVIEW(&__pyx_t_1, 1);
  __pyx_r.data = NULL;
  __pyx_r.memview = NULL;
  __Pyx_AddTraceback("cython_test._get_upper_left_corner", __pyx_clineno, __pyx_lineno, __pyx_filename);
  goto __pyx_L2;
  __pyx_L0:;
  if (unlikely(!__pyx_r.memview)) {
    #ifdef WITH_THREAD
    PyGILState_STATE __pyx_gilstate_save = __Pyx_PyGILState_Ensure();
    #endif
    PyErr_SetString(PyExc_TypeError, "Memoryview return value is not initialized");
    #ifdef WITH_THREAD
    __Pyx_PyGILState_Release(__pyx_gilstate_save);
    #endif
  }
  #ifdef WITH_THREAD
  __Pyx_PyGILState_Release(__pyx_gilstate_save);
  #endif
  __pyx_L2:;
  return __pyx_r;
}

我本以为内存视图上的切片会创建一个新的 struct .如果有必要，我可以接受 struct 被初始化，但我真的不希望获得GIL.有没有办法在没有GIL的情况下实现返回的记忆观看？如果我需要初始化一些东西，我如何才能在不复制可能很大的Numpy数组的情况下做到这一点(我只是在读取它).

Edit:我把这个例子做得更小了:

# cython: language_level=3, boundscheck=False, cdivision=True, wraparound=False, initializedcheck=False, nonecheck=False

cdef float[:] get_upper_left_corner(float[:] arr) noexcept nogil:
    return arr[:2]