Re: How to increase the speed of this program?

"HYRY" <zhangry@xxxxxxxxxx> wrote in message
news:1164699156.682944.97410@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I want to join two mono wave file to a stereo wave file by only using
the default python module.
Here is my program, but it is much slower than the C version, so how
can I increase the speed?
I think the problem is at line #1, #2, #3.

I'm not overly familiar with the array module, but one place you may be
paying a penalty is in allocating the list of 0's, and then interleaving the
larray and rarray lists.

What if you replace lines 1-3 with:

def takeOneAtATime(tupleiter):
for i in tupleiter:
yield i[0]
yield i[1]

oarray = array.array("h",takeOneAtATime(itertools.izip(larray,rarray)))

Or in place of calling takeOneAtATime, using itertools.chain.

oarray = array.array("h", itertools.chain(*itertools.izip(larray,rarray)))

Use itertools.izip (have to import itertools somewhere up top) to take left
and right values in pairs, then use takeOneAtATime to yield these values one
at a time. The key though, is that you aren't making a list ahead of time,
but a generator expression. On the other hand, array.array may be just
building an internal list anyway, so this may just be a wash.

Also, try psyco, if you can, especially with this version. Or pyrex to
optimize this data-interleaving.

HTH,
-- Paul


.

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