[Cython] bug in doc Tutorials/Working with NumPy
Hello, I was learning Cython from this tutorial when I noticed a glitch: Near the end, after boundscheck False, some variables are changed to unsigned int. But this has unexpected consequences: variables t_from and such are not determined correctly, as one of the arguments is negative, but gets cast to unsigned for comaprison. (Yes, this is a weird feature of C.) Actually, the use of unsigned does not seem to have any impact on performance, so I suggest to scratch that part of tutorial. Just explain that with boundscheck off, negaitive indices no longer work. (But there might perhaps be one small improvent in cython itself: with boundscheck off, the index might be cast to unsigned before it is used: this way we probably crash on negative values, instead of silently accessing the negative offset of the array data.) Thank you for nice piece of software, Stepan Kasal ___ cython-devel mailing list cython-devel@python.org https://mail.python.org/mailman/listinfo/cython-devel
Re: [Cython] bug in doc Tutorials/Working with NumPy
Hello, On Mon, Nov 09, 2015 at 09:44:15PM -0800, Robert Bradshaw wrote: > I heartily agree that using unsigned types is the source of much > surprising pain, we shouldn't be recommending it: great, thanks a lot for updating the dev doc instantly. > There's two directives: wraparound and boundscheck. The wraparound > directive can be used to disable the check for negative values. And thanks for catching this; I misunderstood this. Stepan ___ cython-devel mailing list cython-devel@python.org https://mail.python.org/mailman/listinfo/cython-devel
[Cython] [PATCH] docs: link to specific changelog item
Helllo, while reading the docs, I noticed that a link is less specific than possible. The URL points to a section in Python 3.8 Changelog, while the relevant item is about 25th in the list. It took me some time to find out: I wasn't able to realize what is the relevat part of changelog at first. I haven't understood it until I returned to the page after some research elsewhere. Attach please find proposed one-line patch to the docs, against current master. (Sorry, I cannot easily create PR at the moment.) With kind reagrds, Stepan Kasal >From b625dc61a5c1af71295240743e4cde7ddc95c9c3 Mon Sep 17 00:00:00 2001 From: Stepan Kasal Date: Fri, 20 Nov 2020 09:42:07 +0100 Subject: [PATCH] docs: link to specific changelog item --- docs/src/tutorial/appendix.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/docs/src/tutorial/appendix.rst b/docs/src/tutorial/appendix.rst index c76d6f6c3..ea93bb54b 100644 --- a/docs/src/tutorial/appendix.rst +++ b/docs/src/tutorial/appendix.rst @@ -32,7 +32,7 @@ Python 3.8+ --- Since Python 3.8, the search paths of DLL dependencies has been reset. -(`changelog <https://docs.python.org/3/whatsnew/3.8.html#changes-in-the-python-api>`_) +(`changelog <https://docs.python.org/3/whatsnew/3.8.html#bpo-36085-whatsnew>`_) Only the system paths, the directory containing the DLL or PYD file are searched for load-time dependencies. -- 2.27.0.windows.1 ___ cython-devel mailing list cython-devel@python.org https://mail.python.org/mailman/listinfo/cython-devel
