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Re: Slow Show/Graphics in v6.0
*To*: mathgroup at smc.vnet.net
*Subject*: [mg80988] Re: [mg80906] Slow Show/Graphics in v6.0
*From*: Alex Shvydky <ashv at lle.rochester.edu>
*Date*: Fri, 7 Sep 2007 02:04:29 -0400 (EDT)
*References*: <200709050653.CAA26889@smc.vnet.net> <377175200709051434pb7ae575gfe4e7574f72f4379@mail.gmail.com>
Thanks for the input, Ricardo.
They should do something with that. Currently I am running both 5.2 and
v6.0 side by side
and for now most of the code is noticeably slower in 6.0! To the point
it is not usable anymore.
(Of course I could spent couple of days to optimize its etc. etc., but
then it would defeat
the purpose of using Mathematica in the first place - I would rather
then do it in Fortran
or C...)
Like e.g.
profr[r_, s_] := E^(Log[0.05]*r^s);
fonebeam[th_, s_] := profr[Sin[th], s]*Max[0, Cos[th]];
lmax = 10;
Table[
Interpolation[({#1, fonebeam[#1, s]} &) /@ Range[0, Pi,
Pi/(30.*lmax)]];
NIntegrate[finterp[th]*LegendreP[#1, Cos[th]]*Sin[th], {th, 0, Pi},
MaxRecursion -> 16] & /@ Range[0, lmax],
{s, 1.9, 3., 0.02}];
took 3.78sec in Mathematica V5.2 and 39.97sec in V6.0.
There is again an order of magnitude slow down!
I am observing this across the board. Whatever the "improvement" they
introduce in
my view can not justify an order of magnitude slow down!
I hope they work on that and v6.xx will be faster.
It is like a new version or a C or Fortran compiler would come with 10
times larger libraries and features,
but the code it would generate from your old programs would run 10 times
slower.
Alex
Ricardo Samad wrote:
> Dear Alex,
>
> I confirm that some graphic functions rendering became slower in
> Mathematica 6.0.
> I am having a similar problem when trying to display a 480 x 640 data
> array using ListContourPlot or ListPlot3D; In Mathematica 5.2 it took
> a few seconds, in 6.0 it takes minutes, and eventually the Kernel hangs.
> I also would like to know if there´s a setting to speed the rendering up.
>
> Ricardo Samad
>
>
>
> On 9/5/07, *Alex Shvydky* <ashv at lle.rochester.edu
> <mailto:ashv at lle.rochester.edu>> wrote:
>
> Hello,
>
> Just wanted to share my puzzlement (utter disappointment/
> frastration) with a ridiculously slow speed of Show/Graphics
> routines in the v6.0 of Mathematica as compared to 5.2,
> which to me at this point makes v6.0 plain unusable.
>
> Working with hydrodynamic simulations I need to
> visualize the computational grid. So I wrote
> simple Mathematica routines to draw a simulation grid.
> In 5.2 they worked fabulously for the past couple of
> years.
>
> Here's an example.
> First, set up two 2dimensional x- and y-coordinate
> arrays.
>
> Timing[
> mr = 350;
> mt = 350;
> xar = Table[((ir - 1.)/(mr - 1.))*Cos[Pi*((it - 1.)/(mt - 1.))],
> {it, 1, mt}, {ir, 1, mr}];
> yar = Table[((ir - 1.)/(mr - 1.))*Sin[Pi*((it - 1.)/(mt - 1.))],
> {it, 1, mt}, {ir, 1, mr}];
> ]
>
> In v6.0 it took
> Out[3]= {2.312, Null}
> In v5.2 it took
> {0.281 Second, Null}
>
> Which is an order of magnitude difference, but hold on.
> Now let's plot the mesh by simply constructing table
> of edges of all the cells (I am aware that the algorithm
> below is very unoptimized and can be made faster etc. etc.
> It was not my intention to discuss here what should be the
> fastest algorithm to plot a 2-d mesh,
> nor was it my intention to debate the issue why one
> would need to plot such a large mesh in the first place...,
> but rather to compare the execution time for an IDENTICAL
> code on v6.0 and v5.2. and get some confirmation/explanation
> of such a suspiciously slow execution speed!).:
>
> Timing[
> Show[
> Graphics[{Hue[ 0.7], AbsoluteThickness[0.1],
> Table[{Line[{{xar[[it,ir]], yar[[it,ir]]},
> {xar[[it,ir + 1]],yar[[it,ir + 1]]},
> {xar[[it + 1,ir + 1]], yar[[it + 1,ir + 1]]},
> {xar[[it + 1,ir]], yar[[it + 1,ir]]}}]},
> {ir, 1, mr - 1}, {it, 1, mt - 1}]
> }],
> PlotRange -> {{-1, 1}, {0, 1}}, AspectRatio -> 1/2, Axes -> True,
> DisplayFunction -> $DisplayFunction, ImageSize -> 800]]
>
> While the timing as, it is returned by the Timing[] function,
> is smaller in the v6.0:
> {1.703, <Here goes the actual graphics>}
> vs.
> {2.094 Second, -Graphics-}
> in v5.2
>
>
> The actual cell evaluation time in v.6.0 is 124.11 seconds
> vs. 2.22 seconds in v 5.2. ???!!!!!!!
>
> Could anybody please confirm this. Also it would be helpful
> if someone from Wolfram Research would explain if
> that is intended (unavoidable) by design or maybe
> a simple setting (which I am unaware of) or a future patch
> will be able to fix it.
>
> Also, it is horribly slow to resize the above graphics
> in v5.2 you just grab the corned and drag. In v6.0 you
> must do it 10-100 times slower (is it possible
> that I just have a very poor graphics card?).
>
>
> Thanks,
> Alex Shvydky
>
>
>
>
> --
> ____________________________________
> Ricardo Elgul Samad
>
> tel: (+55 11) 3816-9314
> fax: (+55 11) 3816-9315
>
> Centro de Lasers e Aplicações
> IPEN/CNEN-SP
> AV. Prof. Lineu Prestes 2242
> Cidade Universitária
> 05508-000
> São Paulo - SP
> Brazil
> ____________________________________
--
_______________________________________________________________
Alex Shvydky <ashv at lle.rochester.edu>
Research Associate
Computational Design Group
Laboratory for Laser Energetics Office: 1423 COI
University of Rochester Phone: (585) 275-9539
250 East River Road FAX: (585) 275-5960
Rochester NY 14623
_______________________________________________________________
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