Python C module questions

Robert Kern rkern at ucsd.edu
Fri Sep 2 06:18:46 CEST 2005


jbrewer wrote:

[I wrote:]
>>You probably shouldn't post such large pieces of code to the list.
> 
> OK.

BTW, please attribute your quotes.

[Still me:]
>>You mean a docstring on the module object itself?
> 
> Actually, I meant docstrings to the module and the functions, objects,
> methods, whatever else in the module.  My code was derived from the
> Python Cookbook, which left that part out (rather important for
> building real C modules).

In the method definition tables for top-level functions and type methods
there is a place for the docstrings. You had them in your code.

Please read the documentation on writing extensions.

  http://docs.python.org/ext/ext.html

Specifically,

  http://docs.python.org/ext/methodTable.html
  http://docs.python.org/ext/node22.html

[Thomas Heller wrote:]
>>You should give up C with a dumb algorithm running at fast speed.
>>Implement a better algorithm in Python, maybe you can even outperform
>>the dumb code.
> 
> That would be the next step if I needed even more speed, but the better
> algorithm here would be to use KDTrees, which would be overkill (and
> would require lots of development time). 

Not for you, it won't.

google('kdtree python')

> The C brute force
> implementation runs plenty fast for me.  It took only took a few hours
> to implement and yielded a factor of 7 performance increase.  I was
> mostly interested in feedback on whether I had done things in a
> properly efficient way (there are so many Python list / tuple /
> sequence functions).  I also find it hard to believe that there's no
> standard Python function for converting sequences of one object to
> arrays in C (a friend mentioned that Ruby's C API has this).
> 
> Another question: how does the distutils package handle version
> upgrades?  Say for example I find some bugs in my C code and need to
> recompile it, will it just overwrite what's present in the
> site-packages directory?

It will overwrite the files that have been changed.

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
 Are the graves of dreams allowed to die."
  -- Richard Harter




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