Here is my cython code.
self.point_index_array attribute is array whose values increase by 1 from 0.
[0, 1, 2, 3, 4, 5, .....]
The values are normal when first declared, but when the array is accessed from another function, the values of the first four elements are automatically changed.
python and cython version
Here is my sudo code
cdef class KdTree:
cdef uint32_t* point_index_array
def __cinit__(KdTree self):
self.point_index_array = NULL
def __init__(KdTree self,
np.ndarray points not None,
int num_of_leaf=16):
cdef np.ndarray[uint32_t, ndim=1] point_index_list
point_index = np.arange(0, self.num_of_points, dtype=np.uint32)
point_index_list = np.ascontiguousarray(point_index.ravel(), dtype=np.uint32)
self.point_index_array = <uint32_t*>point_index_list.data
# kdtree...
# its normal
self.print_index_array()
def print_index_array(self):
for index in range(10):
print(f"index {index} => {self.point_index_array[index]}")
def neighbor_search(self, float distance):
# values in self.point_index_array are changed
self.print_index_array()
normal output is (__init__)
index 0 => 390
index 1 => 469
index 2 => 493
index 3 => 492
index 4 => 396
index 5 => 490
index 6 => 397
index 7 => 117
index 8 => 484
index 9 => 9
abnormal output is (neighbor_search)
index 0 => 1171518192
index 1 => 504
index 2 => 1174758304
index 3 => 504
index 4 => 396
index 5 => 490
index 6 => 397
index 7 => 117
index 8 => 484
index 9 => 9
I don't understand why this happens at all.
Could you let me know what I'm missing?
@slothrop thanks for your appreciate!
"point_index_list" variable is python object in previous code, so it was removed by GC.
so, i save this object to class attribute.
cdef class KdTree:
cdef uint32_t* point_index_array
cdef readonly np.ndarray point_index_list
def __init__(KdTree self,
np.ndarray points not None,
int num_of_leaf=16):
point_index = np.arange(0, self.num_of_points, dtype=np.uint32)
# this code will prevent CG of point_index_list
self.point_index_list = np.ascontiguousarray(point_index.ravel(), dtype=np.uint32)
self.point_index_array = <uint32_t*>self.point_index_list.data