Variables different between .py and .pyc

[Scott Ransom]

Hello,

I'm running Python 2.0 on Linux and seem to have found a strange problem
when importing floating point variables defined in modules.  I have not
tried this in Python 2.1 so I don't know if the problem exists there as
well.

Here is a simple module (vars.py):

PI    = 3.14159265358979324
TWOPI = 6.28318530717958648

When I import this and check the variable values here is what I get:

presto:~$ python
Python 2.0 (#6, Nov 16 2000, 12:32:08)
[GCC 2.95.2 20000220 (Debian GNU/Linux)] on linux2
Type "copyright", "credits" or "license" for more information.
>>> import vars
>>> vars.PI, vars.TWOPI
(3.1415926535897931, 6.2831853071795862)

All is well, so far.  Now, if I try again (and this time the interpreter
loads from the newly created vars.pyc file):

presto:~$ python
Python 2.0 (#6, Nov 16 2000, 12:32:08)
[GCC 2.95.2 20000220 (Debian GNU/Linux)] on linux2
Type "copyright", "credits" or "license" for more information.
>>> import vars
>>> vars.PI, vars.TWOPI
(3.1415926535900001, 6.2831853071800001)

My variables are truncated at ~12 decimal points of precision.

Removing the .pyc file makes things "better" again...

presto:~$ rm vars.pyc
presto:~$ python
Python 2.0 (#6, Nov 16 2000, 12:32:08)
[GCC 2.95.2 20000220 (Debian GNU/Linux)] on linux2
Type "copyright", "credits" or "license" for more information.
>>> import vars
>>> vars.PI, vars.TWOPI
(3.1415926535897931, 6.2831853071795862)

Any idea why this is happening?

Thanks a bunch,

Scott
-- 
Scott M. Ransom                   Address:  Harvard-Smithsonian CfA
Phone:  (617) 495-4142                      60 Garden St.  MS 10 
email:  ransom at cfa.harvard.edu              Cambridge, MA  02138
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