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[Darren Dale <dsdale24@xxxxxxxxx>]

** Changed in: python-quantities
       Status: Fix Committed => Fix Released

-- 
trying to change units to incompatible units alters some units
https://bugs.launchpad.net/bugs/311698
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Status in Physical Quantities for Python: Fix Released

Bug description:
>>> from quantities import *
from 
>>> from numpy import *
>>> J
Quantity(1.0), kg * m^2 / s^2              #this is correct!
>>> x  = 100 *s
>>> x.units = inch * J                    #now try changing units to something wrong

Traceback (most recent call last):
  File "<pyshell#5>", line 1, in <module>
    x.units = inch * J
  File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/quantities-1.0-py2.5-macosx-10.3-i386.egg/quantities/quantity.py", line 81, in _set_units
    self._units.set_units(units)
  File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/quantities-1.0-py2.5-macosx-10.3-i386.egg/quantities/dimensionality.py", line 101, in set_units
    raise IncompatibleUnits('convert between', self._udunits(), units._udunits())
IncompatibleUnits: Cannot convert between quanitites with units of 's' and 'kg in^3 s^-2'
>>> J
Quantity(1550.0031000061997), kg * m^2 / s^2               # totally wrong! somehow this operation has changed J