New submission from Constantino Antunes: I was using python as my calculator when I got a result which had to be rounded to be the value I expected. So I made some tests with a simple case. Given that 0.38 - 0.20 = 0.18, then 1000.38 - 1000.20 should be also 0.18.
Here is this calculation done on three different systems: Python 2.7.5 (default, Mar 9 2014, 22:15:05) [GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.0.68)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> 0.38 - 0.20 0.18 >>> test = lambda x: (x+0.38) - (x+0.20) >>> test(0) 0.18 >>> test(1000) 0.17999999999994998 >>> test(1000000) 0.18000000005122274 >>> test(1000000000) 0.1799999475479126 >>> test(1000000000000) 0.1800537109375 >>> test(1000000000000000) 0.125 --- Python 2.7.3 (default, Mar 13 2014, 11:03:55) [GCC 4.7.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> 0.38 - 0.20 0.18 >>> test = lambda x: (x+0.38) - (x+0.20) >>> test(0) 0.18 >>> test(1000) 0.17999999999994998 >>> test(1000000000000000) 0.125 --- Python 2.4.3 (#1, Oct 23 2012, 22:02:41) [GCC 4.1.2 20080704 (Red Hat 4.1.2-54)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> 0.38 - 0.20 0.17999999999999999 >>> test = lambda x: (x+0.38) - (x+0.20) >>> test(0) 0.17999999999999999 >>> test(1000) 0.17999999999994998 >>> test(1000000000000000) 0.125 ---------- messages: 226270 nosy: Constantino.Antunes priority: normal severity: normal status: open title: wrong subtraction result versions: Python 2.7 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue22325> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
