[SciPy-dev] physical quantities: udunits?

Charles Doutriaux doutriaux1@llnl....
Fri Aug 1 09:28:29 CDT 2008

Hi Darren,

Here are some examples:
 >>> a = unidata.udunits(1,'m')
 >>> a.to('cm')

You can also use:

Come to think of it I should change it so it only shows units compatible 
with "a"

Anyway, sorry I pointed to the "trunk" version, I forgot it is still 
Numeric based. Or devel version is numpy based.

you can access it at:
svn export 
user: guest
psswd: cdatdevel

It is indeed based on udunits (not udunits2). I should upgrade.

You're right we could probably subclass numpy. Do you want to do it?

Honestly I don't think i'll have time in the next month or so.


Darren Dale wrote:
> Hi Charles,
> On Thursday 31 July 2008 06:56:33 pm you wrote:
>> Ok looks like our security update was a bit too strong :) can you try
>> again ?
> Thanks, I am able to grab the sources now.
> I did a search on the web a few days ago to see if udunits can be used on 
> Windows. The answer appeared to be no, but I tried installing your unidata 
> python package on windows anyway.
> There is no windows binary for Numeric and python-2.5, so I tried a first 
> order workaround by changing the Numeric include in udunits_wrap.c to:
> #include "numpy/arrayobject.h"
> This required importing numpy in your setup script and adding 
> numpy.get_include() to the list of include_dirs in your extension 
> constructor. I also had to modify the path where udunits is installed, in 
> both setup.py and udunits.py. (moving udunits.dat into Lib would allow the 
> library to be installed using distutils package_data, I think.)
> I am happy to say that I was able to build the package with mingw, install it, 
> and run the test script. I didn't see any problems (but I didn't really know 
> what to look for).
> Would you mind posting a link to your udunits2 package?
> Based on your nice work here, and the appearance of windows compatibility, it 
> seems like it shouldn't be too difficult to build a physical_quantities 
> object subclassed from numpy.ndarray. Have you considered this possibility?
> Regards,
> Darren

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