[Python-talk] Profile results... Better pack?

[bruce.labitt at autoliv.com]

kent3737 at gmail.com wrote on 10/15/2009 12:58:47 PM:

> On Thu, Oct 15, 2009 at 11:50 AM,  <bruce.labitt at autoliv.com> wrote:
> 
> > I guess first order of business is to work on packing...
> >
> > Is there a faster packer?  I need to generate a string that is the
> > concatenation of:
> >
> > 1 16 bit number byte swapped + 1084200 doubles byte swapped
> >
> > The byte swapping is to get into network order.
> 
> Can you show your code? I suggest you post this specific question to
> comp.lang.python with a code sample of what you are doing now. Even
> better would be a short, standalone program that demonstrates the
> timing. That newsgroup loves optimization questions.
> 

I don't see why not. 
Do you have to sign up to post?
I don't know how to do the random number generation in straight python...

I think this is a CME (complete minimal example).

# ===============================================
from numpy import random
from struct import pack
import time

lenfft = 10084200
sigma = 0.1
stim = random.normal(0., sigma, lenfft) # 10084200 gaussian random numbers 
(doubles)

fmt = '!h'+str(stim.size)+'d'  # makes fmt = '!h10084200d'
cmd = 4

startTime = time.time()
packdat = pack( fmt, cmd, *stim )
elapsed = time.time() - startTime
print 'Time to pack elements ', elapsed
# ==============================================


> > Can I use the module array?
> 
> It looks promising, it does have byteswap() and tofile() methods...
> 
> Kent


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