[Pyrex] Pyrex v Psyco

[John Machin]

On 19/06/2006 8:59 AM, Philip Smith wrote:
> Hi
>  
> First of all thanks to Greg for Pyrex (which I have come to very 
> recently and which will certainly make wrapping libraries easier)
>  
> I've been looking for an alternative to Psyco for distributing Python 
> apps to other platforms than Win32 - however (while not being in general 
> a 'speed' junkie) I don't want to sacrifice performance.
>  
> I've been trying Pyrex out on a small text search programme which uses 
> the Boyer-Moore algorithm and which I have adapted to search for all 
> occurrences of a string in the given text.
>  
> With algorithmic improvements I managed something like a 10 fold 
> increase in speed performance and Psyco gives me another 10 fold 
> increase.  I've read all the tips and tricks re: Pyrex I can find and 
> tried to implement them but I can't seem to replicate the performance 
> enhancement over Psyco which the Pyrex test suite demonstrates - in fact 
> Psyco wins hands down every time.
>  
> Am I (as a newcomer) doing soething obviously wrong or is there 
> something about this code that means one wouldn't expect particularly 
> fast execution???
>  
> Thanks
>  
> Phil
>  
> This is my pyx file:
>  
> -----------------------------------
>  
> 
> cdef extern from "Python.h":
> 
>     cdef object PySequence_GetItem(object o, int i)

Well as sure as the supreme being made little apples, pysco ain't 
faffing about with PySequence_GetItem()!!!

You need to get a cdef (char *) pointing to the start of each of your 
string args, and a cdef int containing the length of each, then proceed 
as if you were writing the thing in C.