Fix link to 'The Perils of Floating Point', on the tutorial

[aureliobarbosa]

CPython Tutorial "15. Floating Point Arithmetic: Issues and Limitations" links to the document "The Perils of Floating Point", which was written by Bruce M. Bush in 1996, while working for Lahey Software Solutions. The document was hosted by this company, which ceased its activity last year. Fortunately, a copy of the document was kept by by Emeritus professor Brian Junker, from Carnegie Mellon University, which is the document I am linking to right now.

The document provide details on how floating point numbers are represented on computer systems and it should be interesting to keep this reference.

---

📚 Documentation preview 📚: https://cpython-previews--112499.org.readthedocs.build/

[cpython-cla-bot]

All commit authors signed the Contributor License Agreement.

[serhiy-storchaka]

How can we know that this is a legal copy of the document?

[serhiy-storchaka]

BTW, the last snapshot of this document on the Web Archive is http://web.archive.org/web/20230604072523/http://www.lahey.com/float.htm .

[aureliobarbosa]

How can we know that this is a legal copy of the document?

Thanks for the comment and feedback. Further investigation led to find that the author Bruce M. Bush currently hosts a copy of document on his own professional site, through this link. He also grants permission to share the document, but asks to acknowledge the source propertly:

"The Perils of Floating Point by Bruce M. Bush © 1996 Lahey Computer Systems, Inc."

I think it's better to use the new link but about citation, I am not sure whether a company (even a closed one), and an author, should be cited on the python documentation. Personally, I would follow the author, but give me a direction and I follow according the community standard in a new commit.

[serhiy-storchaka]

I think a link should be enough. We do not copy the document, we only provide a link to the original document that contains all necessary copyright information. Everyone who read the document has also access to this information.

[aureliobarbosa]

Thanks @serhiy-storchaka.

[miss-islington-app]

Thanks @aureliobarbosa for the PR, and @serhiy-storchaka for merging it 🌮🎉.. I'm working now to backport this PR to: 3.11.
🐍🍒⛏🤖

[miss-islington-app]

Thanks @aureliobarbosa for the PR, and @serhiy-storchaka for merging it 🌮🎉.. I'm working now to backport this PR to: 3.12.
🐍🍒⛏🤖

[bedevere-app]

GH-112663 is a backport of this pull request to the 3.11 branch.

[bedevere-app]

GH-112664 is a backport of this pull request to the 3.12 branch.

[serhiy-storchaka]

Thank you for your contribution @aureliobarbosa.