[issue6198] test_float fails on Windows
Eric Smith e...@trueblade.com added the comment: In r73314, I restored the one test erroneously removed (%#.0f 1.5 - 2.). -- resolution: - fixed status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Changes by Antoine Pitrou pit...@free.fr: -- nosy: +marketdickinson ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Changes by Eric Smith e...@trueblade.com: -- nosy: +eric.smith ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Eric Smith e...@trueblade.com added the comment: I can duplicate this with Visual C++ 9.0 Express Edition on XP. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Mark Dickinson dicki...@gmail.com added the comment: Thanks for the report. It sounds as though I might have backported some tests from py3k to trunk that shouldn't have been backported. abbeyj or eric, do you know whether py3k also has this failure on your machine? I'm hoping not: py3k doesn't use the CRT *printf functions for float formatting, so the test should pass there. -- assignee: - marketdickinson ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Eric Smith e...@trueblade.com added the comment: Yes, this test passes on py3k on my Windows box. That would be a nightmare if it didn't! I agree that this is a test problem, not a code problem. I suggest we just remove the offending line from formatfloat_testcases.txt in trunk. I can do this and verify it works on Windows before checking in, if you'd like. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Mark Dickinson dicki...@gmail.com added the comment: [Eric] I can do this and verify it works on Windows before checking in, if you'd like. That would be great---yes, please! My main computer died yesterday, taking my Windows access and my python svn access with it. :-( -- assignee: marketdickinson - eric.smith ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Eric Smith e...@trueblade.com added the comment: I had to remove a bunch of tests. Some were of the form even-number5, rounded to before the 5. Some were comparing a large number of digits. Then there's these: %#.0g 0 - 0. Got '0.0' %#.1g 0 - 0. Got '0.0' %#.2g 0 - 0.0Got '0.00' %#.3g 0 - 0.00 Got '0.000' %#.4g 0 - 0.000 Got '0.' I'm going to remove these, too, since they're all based on underlying printf differences. But they seem like a bigger problem than the other cases. -- assignee: eric.smith - marketdickinson ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Eric Smith e...@trueblade.com added the comment: Checked in to trunk in r73240. -- assignee: marketdickinson - eric.smith resolution: - fixed stage: - committed/rejected status: open - closed type: - behavior ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Mark Dickinson dicki...@gmail.com added the comment: Thanks, Eric. All those changes look good to me. Out of interest, what does '%#.0f' % 1.5 produce on Python 2.7/Windows? I'd expect to get '2.' both for round-half-to-even and round-half-away-from-zero. Does Windows round this down to '1.' instead? I'm surprised by the %#.ng results for 0; this looks like questionable behaviour (producing n+1 digits when only n significant digits were requested). Is the MS implementation of printf directly responsible for this, or is the CPython code somehow adding the extra 0? If this is just the way that Windows behaves for formatting of zeros, then I suppose we could add code to work around this, but it's not clear that it's really worth it. I suspect that we're in for some complaints when Windows users discover that Python 3.1 string formatting does round-half-to-even rather than the round-half-up they're used to in Python 2.x. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Tim Peters tim.pet...@gmail.com added the comment: Out of interest, what does '%#.0f' % 1.5 produce on Python 2.7/Windows? Microsoft's float-string routines have always done add a half and chop rounding. So, yes, 1.5 rounds to 2 there. ... I suspect that we're in for some complaints when Windows users discover that Python 3.1 string formatting does round-half-to-even rather than the round-half-up they're used to in Python 2.x. Historically, overall we've had more gripes from non-Windows users complaining that, e.g., 2.5 does /not/ round up to 3 -- you can't win here, so don't worry about it. X-platform consistency is incompatible with platform-specific behavior, and most users will agree consistency is overwhelmingly more important. Of course that won't deter them from complaining ;-) -- nosy: +tim_one ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Eric Smith e...@trueblade.com added the comment: Mark Dickinson wrote: Out of interest, what does '%#.0f' % 1.5 produce on Python 2.7/Windows? I'd expect to get '2.' both for round-half-to-even and round-half-away-from-zero. Does Windows round this down to '1.' instead? Windows in trunk gives '2.'. I'm surprised by the %#.ng results for 0; this looks like questionable behaviour (producing n+1 digits when only n significant digits were requested). Is the MS implementation of printf directly responsible for this, or is the CPython code somehow adding the extra 0? If this is just the way that Windows behaves for formatting of zeros, then I suppose we could add code to work around this, but it's not clear that it's really worth it. This is from a C program on Windows, using printf: %#.0g: 0.0 %#.1g: 0.0 %#.2g: 0.00 %#.3g: 0.000 Same program on Linux: %#.0g: 0. %#.1g: 0. %#.2g: 0.0 %#.3g: 0.00 In 2.6 on Windows: '%#.1g' % 0.0 '0.0' '%#.2g' % 0.0 '0.00' In 2.6 on Linux: '%#.1g' % 0.0 '0.' '%#.2g' % 0.0 '0.0' So this isn't a problem we caused with the short repr work, it's pre-existing. I don't think it's worth working around, but that's me. %-formatting should just die. I suspect that we're in for some complaints when Windows users discover that Python 3.1 string formatting does round-half-to-even rather than the round-half-up they're used to in Python 2.x. But at least in 3.1 it will now be consistent cross-platform. Can't have it both ways! -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Mark Dickinson dicki...@gmail.com added the comment: [Mark] Out of interest, what does '%#.0f' % 1.5 produce on Python 2.7/Windows? I'd expect to get '2.' both for round-half-to-even and round-half-away-from-zero. Does Windows round this down to '1.' instead? [Eric] Windows in trunk gives '2.'. Thanks. I was mainly wondering why you'd commented out the line %#.0f 1.5 - 2. in the formatfloat_testcases.txt file. [Eric, about zero formatting on Windows] So this isn't a problem we caused with the short repr work, it's pre-existing. I don't think it's worth working around, but that's me. I agree it doesn't seem worth working around. Let's wait until somebody complains. :-) -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
Eric Smith e...@trueblade.com added the comment: [Mark] Out of interest, what does '%#.0f' % 1.5 produce on Python 2.7/Windows? I'd expect to get '2.' both for round-half-to-even and round-half-away-from-zero. Does Windows round this down to '1.' instead? [Eric] Windows in trunk gives '2.'. [Mark] Thanks. I was mainly wondering why you'd commented out the line %#.0f 1.5 - 2. in the formatfloat_testcases.txt file. Over-zealous commenting out on my part. I'm away from my Windows box, but I'll correct this next week and check it back in with that line re-enabled. Thanks for catching that. -- resolution: fixed - status: closed - open ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6198] test_float fails on Windows
New submission from James Abbatiello abb...@gmail.com: test_float fails on Windows with: == FAIL: test_format_testfile (test.test_float.IEEEFormatTestCase) -- Traceback (most recent call last): File C:\Projects\python-trunk\lib\test\test_float.py, line 319, in test_format_testfile self.assertEqual(fmt % float(arg), rhs) AssertionError: '3' != '2' -- The problematic line from formatfloat_testcases.txt is: %.0f 2.5 - 2 On some systems *printf() uses round-to-even. But the Windows CRT uses round-half-away-from-zero. Consider the following C code: printf(%+.1f - %+.0f\n, -2.5, -2.5); printf(%+.1f - %+.0f\n, -1.5, -1.5); printf(%+.1f - %+.0f\n, +1.5, +1.5); printf(%+.1f - %+.0f\n, +2.5, +2.5); On Linux this will produce: -2.5 - -2 -1.5 - -2 +1.5 - +2 +2.5 - +2 And on Windows: -2.5 - -3 -1.5 - -2 +1.5 - +2 +2.5 - +3 -- components: Tests, Windows messages: 88922 nosy: abbeyj severity: normal status: open title: test_float fails on Windows versions: Python 2.7 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6198 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
