Bugs item #1080440, was opened at 2004-12-07 06:24 Message generated for change (Comment added) made by mwh You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1080440&group_id=5470
Category: Python Interpreter Core Group: None Status: Open Resolution: None Priority: 5 Submitted By: Dileep Nirala (dileep_nirala) Assigned to: Nobody/Anonymous (nobody) Summary: float issue for NaN type in .pyc file Initial Comment: There is a difference in output between .pyc and .py file, while dealing with NaN float. In fact I am doing a float range validation as part of my requirement. The content of my sample program [test.py] aboveMax = 1.8e+308 belowMin = -1.8e+308 print aboveMax, belowMin While execution: command: python test.py output: 1.#INF -1.#INF This output is expected and good, however if I use compiled python file as below, command: python test.pyc output: 1.0 -1.0 This output is wrong, it does not show Nan floating point. ---------------------------------------------------------------------- >Comment By: Michael Hudson (mwh) Date: 2004-12-07 14:51 Message: Logged In: YES user_id=6656 I know first hand how much of a pain this issue can be. However it's not clear what can be done about it. My vote would go towards complaining at compile time that the literals cannot be represented as a regular double, but even that isn't the easiest thing to do portably! ---------------------------------------------------------------------- Comment By: Dileep Nirala (dileep_nirala) Date: 2004-12-07 13:54 Message: Logged In: YES user_id=1173293 My test cases passes for the first time but fails second times onward since .pyc gets loaded since it's existing. ---------------------------------------------------------------------- Comment By: Tim Peters (tim_one) Date: 2004-12-07 07:51 Message: Logged In: YES user_id=31435 Python guarantees nothing about behavior in the presence of NaNs, infinities, or signed zeroes. Anything you see then is a platform-dependent accident. This should be closed with a reference to PEP 42 (I don't have time to look it all up now -- "non-accidental" IEEE behavior is a longstanding feature request, but one unlikely to be resolved in the foreseeable future; the particular problem here is that the marshal format deals in accidental ways with infinities, NaNs, and signed zeroes, so accidents in .py files may not be reproduced from .pyc files) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1080440&group_id=5470 _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
