speed of python vs matlab.
I've been trying to develop some numerical codes with python, however got disappointed. A very simple test, a = 1.0 for i in range(1000): for j in range(1000): a = a+1 unfortunately, it took 4.5 seconds to finish(my machines is fine. P4 3.0G, 1G RAM, it varies according to machine configuration, but should be in the same level) for matlab, the same operation took 0.1 seconds, I use numpy & scipy, they solve the problem most of the times, but there are cases you can't avoid loops by vectors. I appreciate the elegancy of python so much, but I guess I have to gave it up in these numerical codes.(image processing algorithms), for application dev/scripting, it's still my first choice. A good news is that the same code takes ruby 9.8 seconds. -- http://mail.python.org/mailman/listinfo/python-list
Re: speed of python vs matlab.
My Bad, the time used by python is 0.46~0.49 sec, I tried xrange, but it doesn't make things better. import time tic = time.time() a = 1.0 array = range(1000) for i in array: for j in array: a = a + 0.1 toc = time.time() print toc-tic,' has elapsed' used by matlab is 0.012sec tic a = 1; for i=1:1000 for j=1:1000 a = a + 1; end end toc used by ruby is 0.94~0.96sec a = 1 start = Time.now() 1000.times do 1000.times do a = a + 1 end end finish = Time.now() puts finish - start Andrew Sackville-West wrote: > On Wed, Dec 13, 2006 at 04:07:20PM -0800, Chao wrote: > > I've been trying to develop some numerical codes with python, however > > got disappointed. > > > > A very simple test, > > > > a = 1.0 > > > > for i in range(1000): > > for j in range(1000): > >a = a+1 > > > > unfortunately, it took 4.5 seconds to finish(my machines is fine. P4 > > 3.0G, 1G RAM, it varies according to machine configuration, but should > > be in the same level) > > somethings not right there. > > [EMAIL PROTECTED]:~$ cat pytimetest.py > a=1.0 > for i in range (1000): > for j in range (1000): > a=a+1 > > > [EMAIL PROTECTED]:~$ time python pytimetest.py > > real0m0.534s > user0m0.528s > sys 0m0.000s > > > [EMAIL PROTECTED]:~$ cat /proc/cpuinfo | grep name > model name : Intel(R) Celeron(R) CPU 2.53GHz > > [EMAIL PROTECTED]:~$ uname -a > Linux debian 2.6.18-3-686 #1 SMP Mon Dec 4 16:41:14 UTC 2006 i686 > GNU/Linux > > A > > --7AUc2qLy4jB3hD7Z > Content-Type: application/pgp-signature > Content-Disposition: inline; > filename="signature.asc" > Content-Description: Digital signature > X-Google-AttachSize: 190 -- http://mail.python.org/mailman/listinfo/python-list
Re: speed of python vs matlab.
Thank you guys for your interest, I tried two things 1) put code into a function 2) use psyco. 1) by putting them into a function, there is a significant improvement, around 30% the running time will be around 0.3sec 2) by using psyco, it really does a great job, the running time is around 0.045sec. While trying this another question comes up, psyco seems to be able to optimize built-in functions & user's code, if I call a function from an external library, it seems doesn't help. A simple thing is I placed a = numpy.sin(a) in the loop rather than a = a+1, in this case, psyco doesn't have any improvement(or very little). if I put a = math.sin(a) which is from an built-in function, it can achieve a improvement around 3~4. Could the reason be that numpy.sin is actually calling a C library ? Actually Python does show comparable/better performance than other scripting languages. but I'm just surprised that matlab does a great job compared to python/perl, since matlab is also a interpreted language, I'm expecting it has silimar performance with python. I did some search, in previous discussion, people has compared python/numpy vs matlab, but it is actually comparison between numpy(which is implemented in c) vs matlab. Chao. import psyco #psyco.bind(functest) psyco.full() import numpy import time,math def functest(a): array = xrange(1000) for i in array: for j in array: a = a + 1 tic = time.time() a = 1.0 functest(a) toc = time.time() print toc-tic,' has elapsed' [EMAIL PROTECTED] wrote: > Chao, you can also try Psyco, applied on functions, and when necessary > using its metaclass too. > > Bye, > bearophile -- http://mail.python.org/mailman/listinfo/python-list
where to find shared python script?
Dear all, I am new to python and thank you for your help! the first question is, is there any resource online where we can find shared python script (like reading a csv file for ready plot making, I know to use csv module while I find it's not good enough) . The second one is, is there a search function in the our mailing list archive http://mail.python.org/pipermail/python-list/. ? Best, Chao -- *** Chao YUE Laboratoire des Sciences du Climat et de l'Environnement (LSCE-IPSL) UMR 1572 CEA-CNRS-UVSQ Batiment 712 - Pe 119 91191 GIF Sur YVETTE Cedex Tel: (33) 01 69 08 77 30 Portable Phone (Mobil phone) : (33) 07 60 54 23 71 -- http://mail.python.org/mailman/listinfo/python-list
How to use the method loadtxt() of numpy neatly?
HI, everybody. When I try to use numpy to deal with my dataset in the style
of csv, I face a little problem.
In my dataset of the csv file, some columns are string that can not convert
to float easily. Some of them can ignore, but other columns I need to change
the data to a enum style.
for example, one column just contain three kinds : S,Q,C. Each of them can
declare one meaning, so I must convert them to a dict just like {1,2,3}
Now the question is, when I use numpy.loadtxt, I must do all things above
in just one line and one fuction. So as a new user in numpy, I don't know how
to solve it.
Thank you.
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socket on cygwin python
I've installed cygwin with latest python 2.5.1, but it seems that the socket lib file do NOT support IPv6(cygwin\lib\python2.5\lib-dynload \_socket.dll), what can I do if I want to use IPv6? Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: socket on cygwin python
On Jun 25, 1:26 pm, "Martin v. Löwis" <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED] schrieb: > > > I've installed cygwin with latest python 2.5.1, but it seems that the > > socket lib file do NOT support IPv6(cygwin\lib\python2.5\lib-dynload > > \_socket.dll), what can I do if I want to use IPv6? > > Use the Python binaries from python.org. If that is not acceptable, > recompile Python for Cygwin to use WinSock2. > > Regards, > Martin Thanks Martin. But no VC/C++ tool installed on my PC, and I think recompile this file it seems necessary. :( So I tried to find a binary files on Python.org, but I can't find it. Could you tell me the binary location for the file? Thank you. BestRegards Ming -- http://mail.python.org/mailman/listinfo/python-list
Re: socket on cygwin python
On Jun 26, 12:49 am, Jason Tishler <[EMAIL PROTECTED]> wrote: > On Mon, Jun 25, 2007 at 01:53:18PM +0100, Michael Hoffman wrote: > > [EMAIL PROTECTED] wrote: > > > I've installed cygwin with latest python 2.5.1, but it seems that the > > > socket lib file do NOT support IPv6(cygwin\lib\python2.5\lib-dynload > > > \_socket.dll), what can I do if I want to use IPv6? > > > I don't think Cygwin supports IPv6. > > That was my impression too and seems to be substantiated by the > following: > >http://win6.jp/Cygwin/index.html > > Jason > > -- > PGP/GPG Key:http://www.tishler.net/jason/pubkey.ascor key servers > Fingerprint: 7A73 1405 7F2B E669 C19D 8784 1AFD E4CC ECF4 8EF6 Got it! Thank you very much, Jason, both Michael. I've chosen to be a Linuxer not only to solve this. :) Ming -- http://mail.python.org/mailman/listinfo/python-list
way to define static method
I think Python uses a very strange way to define static method in a class. Why not make it like this? class MyClass: def my_static_method(self): # self should be None as it's a static method # just ignore self I'm a newcomer so maybe it's quite naive. But I just wonder why it is designed like this. Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: way to define static method
Thanks a lot.
Because I found a solution about static method from
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52304
And that's a little bit difficult to understand.
# direct, naive approach -- doesn't work...:
class Class1:
def static1(name):
print "Hello",name
# ...but now, a call such as:
Class1.static1("John")
# will fail with a TypeError, as 'static1' has become
# an unbound-method object, not a plain function.
# This is easy to solve with a simple tiny wrapper:
class Callable:
def __init__(self, anycallable):
self.__call__ = anycallable
# toy-example usage:
class Class2:
def static2(name):
print "Hi there",name
static2 = Callable(static2)
# now, a call such as:
Class2.static2("Peter")
# works just fine, and as-expected
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Re: IDE for Python
I think many python developers don't need such an IDE actually. Just like Ruby guys, they use a powerful editor, for example, Textmate, instead of all-in-one IDE. It's quick and direct. On 8/21/07, Joel Andres Granados <[EMAIL PROTECTED]> wrote: > Hello list: > > I have tried various times to use an IDE for python put have always been > disapointed. > I haven't revisited the idea in about a year and was wondering what the > python people > use. > I have also found http://pida.co.uk/main as a possible solution. Anyone > tried it yet? > > suggestions. > Regards > Joel Andres Granados > > -- > http://mail.python.org/mailman/listinfo/python-list > > -- http://mail.python.org/mailman/listinfo/python-list
when will python 2.5 take in mainstream?
A lot of application based on python claim that python 2.3 or 2.4 is needed not 2.5, ie. mysqldb. I've been using python for months. I don't care about 2.4 or 2.5. But I like the default icons of python in 2.5. So I just use that, but some scripts can't work on that. When will all these applications support 2.5? Thanks. -- http://mail.python.org/mailman/listinfo/python-list
connection pool in python?
Connection Pool is necessary in web applications with Java and JDBC. So does python have something like that? Thanks. -- http://mail.python.org/mailman/listinfo/python-list
convert python scripts to exe file
I know py2exe can make an exe file. But python runtime dll is still there. How can I combine the dll file into the exe, just make one file? Thanks. -- http://mail.python.org/mailman/listinfo/python-list
How to use dbstore in google app engine
Hi all: I have a question. How GEA save a file as simulates the App Engine datastore in local computer? where is the file? thank you -- http://mail.python.org/mailman/listinfo/python-list
Plotting Images
Hi ALL: I have only been switched from matlab to python few months ago. I having trouble of plotting images from a matrix size of 8x1 (unfortunately that is the size of my data.) for example, x = rand(8,1) inshow(x) I have tried to use matplotlib function imshow(), but all i get is a long thin line (unable to see the color display and the my matrix information). i think imshow() has the same problem in matlab, but i think there is a alternative in matlab, imagesc(). I did search on web about plt.imagesc().but when i try to run the example code, python just tell me cannot find module plt. >>>from scipy import plt ImportError: cannot import name plt I have installed scipy, wxpython2.6and it still seem not to work! is there some alternitive? or what have i done wrong? Thank you Pei 想及時通知通訊錄裡的所有親朋好友好消息，就來 Yahoo!奇摩電子信箱發簡訊！ http://tw.mobile.yahoo.com/texts/mail.php -- http://mail.python.org/mailman/listinfo/python-list
