Cython:(为什么/何时)使用 Py_ssize_t 进行索引是否更可取? [英] Cython: (Why / When) Is it preferable to use Py_ssize_t for indexing?
问题描述
这是这个问题.
(为什么/何时)使用 Py_ssize_t
进行索引是否更可取?在 docs 我刚刚找到
# Purists 可以使用Py_ssize_t",这是正确的 Python 类型# 数组索引.
-> 这是否意味着在索引 NumPy/Cython 时总是 - 数组/视图应该使用 Py_ssize_t
?
-> 是 Py_ssize_t
e.G.一个 unsigned int
这样我就不能使用 @cython.boundscheck(False)
Py_ssize_t
已签名.请参阅 PEP 353,其中说引入了一种新类型 Py_ssize_t,它具有与编译器的 size_t 类型大小相同,但有符号.如果可用,它将是 ssize_t 的 typedef."
您应该使用 Py_ssize_t
进行索引.我没有在 Cython 文档中找到明确的声明,但是 Cython 开发人员 Stefan Behnel 在一封电子邮件中说了同样多的话(https://groups.google.com/forum/#!topic/cython-users/brENF_M9zxM):
一般来说,您使用整数作为索引.你应该改用 Py_ssize_t 类型(或 size_t,如果你喜欢无符号类型)以正确适应 64 位架构.
This is a follow-up to this question.
(Why / When) Is it preferable to use Py_ssize_t
for indexing? In the docs I just found
# Purists could use "Py_ssize_t" which is the proper Python type for # array indices.
-> Does that mean always when indexing NumPy/Cython - array(s)/-views one should use Py_ssize_t
?
-> Is Py_ssize_t
e. g. an unsigned int
so that I can't used @cython.boundscheck(False)
Py_ssize_t
is signed. See PEP 353, where it says "A new type Py_ssize_t is introduced, which has the same size as the compiler's size_t type, but is signed. It will be a typedef for ssize_t where available."
You should use Py_ssize_t
for indexing. I didn't find a definitive statement of this in the Cython docs, but Stefan Behnel, a Cython developer, said as much in an email (https://groups.google.com/forum/#!topic/cython-users/brENF_M9zxM):
As a general remark, you are using ints as indices. You should use the Py_ssize_t type instead (or size_t, if you prefer an unsigned type) to properly accommodate for 64 bit architectures.
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