Ah, the culprit was the preparser. Thank you; disregard my previous
comments.
On Nov 21, 6:50 pm, William Stein <wst...@gmail.com> wrote:
> On Sun, Nov 21, 2010 at 4:53 PM, Eviatar <eviatarb...@gmail.com> wrote:
> > It is actually slower, not just feels like it. Here is a specific
> > example:
>
> > On Sage Notebook (locally):
>
> > "from numpy import zeros
> > from random import randint
>
> > def cellular(rule, N, initial='Single-cell'):
> > '''Yields a matrix showing the evolution of a Wolfram's cellular
> > automaton
>
> > rule: determines how a cell's value is updated, depending on
> > its neighbors
> > N: number of iterations
> > initial: starting condition; can be either single-cell or a
> > random binary row
> > '''
> > M=zeros( (N,2*N+2), dtype=int)
> > if initial=='Single-cell':
> > M[0,N]=1
> > else:
> > M[0]=[randint(0,1) for a in range(0,2*N+2)]
>
> > for j in range(1,N):
> > for k in range(0,2*N):
> > l = 4*M[j-1,k-1] + 2*M[j-1,k] + M[j-1,k+1]
> > M[j,k]=rule[ l ]
> > return M[:,:-1]
>
> > def num2rule(number):
> > if not 0 <= number <= 255:
> > raise Exception('Invalid rule number')
> > binary_digits = number.digits(base=2)
> > return binary_digits + [0]*(8-len(binary_digits))
>
> > import time
>
> > initial=time.clock()
> > m=cellular(num2rule(90), 100)
> > print time.clock()-initial"
>
> > In Notebook, this returns 5.06. In command-line the same code produces
> > an output of 0.11 seconds.
>
> This has absolutely nothing to do with the notebook. You can't have
> this happen if you are actually running the same code. I just tried
> this and I get about 5 seconds both in the notebook and on the command
> line. *Precisely* how are you running the code on the command line?
> You can't just paste it in, since it isn't formatted for that. So
> maybe you are saving it to a .py file, then using load or import? If
> you do that, then you'll get much, much different times, because of
> the Sage preparser, which is not being used on .py files.
>
> Try the following in the notebook:
>
> (1) Make a cell with exactly this content, and evaluate it:
>
> %python
> from numpy import zeros
> from random import randint
>
> def cellular(rule, N, initial='Single-cell'):
> '''Yields a matrix showing the evolution of a Wolfram's cellular
> automaton
>
> rule: determines how a cell's value is updated, depending on
> its neighbors
> N: number of iterations
> initial: starting condition; can be either single-cell or a
> random binary row
> '''
> M=zeros( (N,2*N+2), dtype=int)
> if initial=='Single-cell':
> M[0,N]=1
> else:
> M[0]=[randint(0,1) for a in range(0,2*N+2)]
>
> for j in range(1,N):
> for k in range(0,2*N):
> l = 4*M[j-1,k-1] + 2*M[j-1,k] + M[j-1,k+1]
> M[j,k]=rule[ l ]
> return M[:,:-1]
>
> def num2rule(number):
> if not 0 <= number <= 255:
> raise Exception('Invalid rule number')
> binary_digits = number.digits(base=2)
> return binary_digits + [0]*(8-len(binary_digits))
>
> (2) Make another cell with this content and evaluate it:
>
> import time
> initial=time.clock()
> m=cellular(num2rule(90), 100)
> print time.clock()-initial
>
> You'll get a fast timing.
>
> It would be good for you to learn about the Sage preparser more, since
> in some cases turning it off (or at least explicitly not using it) can
> lead to better performance, especially for numerical code. Turning it
> off can also lead to much slower (or wrong) code, but usually in the
> context of symbolic (not numerical) computation.
>
> William
>
>
>
>
>
>
>
>
>
>
>
> > On Nov 21, 2:27 pm, William Stein <wst...@gmail.com> wrote:
> >> On Sun, Nov 21, 2010 at 2:25 PM, William Stein <wst...@gmail.com> wrote:
> >> > On Sun, Nov 21, 2010 at 1:33 PM, Eviatar <eviatarb...@gmail.com> wrote:
> >> >> I don't know if this is related, but I've noticed even the local Sage
> >> >> Notebook is slower than command-line, specifically NumPy operations.
>
> >> > It makes absolutely no sense that that could happen. Please give a
> >> > specific example.
>
> >> More precisely, please define exactly what you mean by "slower". Do you
> >> mean:
>
> >> (1) it "feels" slower,
> >> (2) the time from press shift-enter until you see output is longer, or
> >> (3) When you use "time a_specific_command(...)", it takes longer.
>
> >> What I don't think could happen is (3). Obviously (1) or (2) could
> >> happen, due to the client server architecture.
> >> However, this would have absolutely nothing to do with numpy, and you
> >> would notice the same slowdown with
> >> any code in Sage.
>
> >> William
>
> >> > -- William
>
> >> >> On Nov 21, 12:30 pm, William Stein <wst...@gmail.com> wrote:
> >> >>> On Sun, Nov 21, 2010 at 5:23 AM, tuxiano <tuxi...@gmail.com> wrote:
> >> >>> > Please, don't disablewww.sagenb.org
> >> >>> > I'm not an administrator of my office PC so I can't install SAGE and
> >> >>> > my company filters connections not on port 80 or 8080 so
> >> >>> > www.sagenb.org
> >> >>> > is the only Sage implementation that I can use.
>
> >> >>> There is alsohttp://demo.sagenb.organdhttp//demo2.sagenb.org.
>
> >> >>> William
>
> >> >>> > Perhaps other people
> >> >>> > are in my condition.
>
> >> >>> > Thanks
>
> >> >>> > Tiziano
>
> >> >>> > On Nov 21, 3:18 am, Jeroen Demeyer <jdeme...@cage.ugent.be> wrote:
> >> >>> >> On 2010-11-20 22:45, William Stein wrote:
>
> >> >>> >> > (1) I simply totally disablewww.sagenb.org,
>
> >> >>> >> Maybe keepwww.sagenb.orgasitisbut remove the link from the Sage
> >> >>> >> front page?
>
> >> >>> > --
> >> >>> > To post to this group, send an email to sage-devel@googlegroups.com
> >> >>> > To unsubscribe from this group, send an email to
> >> >>> > sage-devel+unsubscr...@googlegroups.com
> >> >>> > For more options, visit this group
> >> >>> > athttp://groups.google.com/group/sage-devel
> >> >>> > URL:http://www.sagemath.org
>
> >> >>> --
> >> >>> William Stein
> >> >>> Professor of Mathematics
> >> >>> University of Washingtonhttp://wstein.org
>
> >> >> --
> >> >> To post to this group, send an email to sage-devel@googlegroups.com
> >> >> To unsubscribe from this group, send an email to
> >> >> sage-devel+unsubscr...@googlegroups.com
> >> >> For more options, visit this group
> >> >> athttp://groups.google.com/group/sage-devel
> >> >> URL:http://www.sagemath.org
>
> >> > --
> >> > William Stein
> >> > Professor of Mathematics
> >> > University of Washington
> >> >http://wstein.org
>
> >> --
> >> William Stein
> >> Professor of Mathematics
> >> University of Washingtonhttp://wstein.org
>
> > --
> > To post to this group, send an email to sage-devel@googlegroups.com
> > To unsubscribe from this group, send an email to
> > sage-devel+unsubscr...@googlegroups.com
> > For more options, visit this group
> > athttp://groups.google.com/group/sage-devel
> > URL:http://www.sagemath.org
>
> --
> William Stein
> Professor of Mathematics
> University of Washingtonhttp://wstein.org
--
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