[Matplotlib-users] Matplotlib ate my real numbers?

[yardbird <yar...@ne...>]

Hello,

I have a very weird problem with matplotlib and reals. Before starting to 
explain please let me apologize, I'm a newbie in Python and I suspect I'm 
doing something horribly wrong.

I have exposed in Python a C++ class with Boost::Python (in the form of a 
shared object). This class (among other things) reads from a file a list of 
real numbers, and stores them internally as doubles.

What happens is that when using matplotlib my exposed class internally begins 
to treat reals like they were integers. In other words, when reading reals 
from a file they are stored as integers, as can be seen by printing the 
contents of the class to screen: all decimal parts are truncated (i.e., 
3.85000E5 instead of 3.8500052719E5). This is _not_ some kind of 
visualization bug, since my class discards reals whose absolute value is 
(almost) zero and indeed when using matplotlib the class loads fewer "reals" 
from the very same file (in other words, values whose abs is < 1 are seen as 
zeroes and as such they get discarded: all reals whose abs is < 1 are missing 
when using matplotlib).

This is extremely strange to me, since I really don't get how matplotlib can 
influence the internal behaviour of my class. Is there somewhere some 
directive in python that can setup the floating point unit?

The "bug" happens exactly after loading matplotlib, without it everything is 
alright. The C++ code from which the class derives has been tested quite 
thoroughly, so I don't think the problem stems from there.

Any pointer would be greatly appreciated :) Thanks very much,

  Francesco (please CC as I'm not subscribed)