[PYTHON MATRIX-SIG] Another problem?
Fri, 16 Aug 1996 20:36:25 +0200 (MET DST)
>>>>> "JH" == Jim Hugunin <firstname.lastname@example.org> writes:
JH> Rob.Hooft@embl-heidelberg.de wrote:
>> factor took 10.577 seconds
>> afactor took 7.916 seconds
JH> I'm running on a faster machine than you, so my numbers are
JH> faster in both cases, still the relative comparision is valid.
JH> factor took 2.708 seconds
JH> afactor took 0.322 seconds
Your machine isn't much faster, it is the python virtual machine that
is much faster :-\. With your version on my box:
factor took 10.327 seconds
afactor took 0.475 seconds
see? I'm running on a 150MHz alpha here, so speed isn't that bad, it is
just that python is juggling 64bit entities everywhere....
JH> Here's my new version of your afactor and asieve functions.
JH> #Set multiples of i to be nonprime
JH> numbers[(i*i)::i] = 0
Right. That is the key. I've been wondering how to do that without
realizing that slices like this are incredibly powerful.
BUT: there is a bug in your script: try running it with upto=999999
IndexError: invalid slice
:-) If the bug is fixed, the behaviour is almost o(N).
BTW: I'm running on an ALPHA, and I also get a crash when combining arrays
with long integers. "gdb" tells me we're somewhere in "PyObject_Str"....
=== Rob.Hooft@EMBL-Heidelberg.DE http://www.Sander.EMBL-Heidelberg.DE/rob/ ==
==== In need of protein modeling? http://www.Sander.EMBL-Heidelberg.DE/whatif/
Validation of protein structures? http://biotech.EMBL-Heidelberg.DE:8400/ ====
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