Albert-Jan Roskam, 02.07.2011 11:49:
Some time ago I finished a sav reader for Spss .sav data files (also with the
help of some of you!):
http://code.activestate.com/recipes/577650-python-reader-for-spss-sav-files/
It works fine, but it is not fast with big files. I am thinking of implementing
two of the functions in cython (getValueChar and getValueNum).
As far as I understood it requires the functions to be re-written in a
Python-like langauge
"rewritten" only in the sense that you may want to apply optimisations or
provide type hints. Cython is Python, but with language extensions that
allow the compiler to apply static optimisations to your code.
, 'minus the memory manager'.
Erm, not sure what you mean here. Cython uses the same memory management as
CPython.
That little piece of code is
converted to C and subsequently compiled to a .dll or .so file. The original
program listens and talks to that .dll file. A couple of questions:
-is this a correct representation of things?
More or less. Instead of "listens and talks", I'd rather say "uses". What
you get is just another Python extension module which you can use like any
other Python module.
-will the speed improvement be worthwhile? (pros)
Depends. If your code is I/O bound, then likely not. If the above two
functions are true CPU bottlenecks that do some kind of calculation or data
transformation, it's likely going to be faster in Cython.
-are there reasons not to try this? (cons)
If your performance problem is not CPU related, it may not be worth it.
-is it 'sane' to mix ctypes and cython for nonintensive and intensive
operations, respectively?
Why would you want to use ctypes if you can use Cython?
Stefan
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