Re: Slow Show/Graphics in v6.0

*To*: mathgroup at smc.vnet.net*Subject*: [mg80977] Re: [mg80906] Slow Show/Graphics in v6.0*From*: "Ricardo Samad" <resamad at gmail.com>*Date*: Thu, 6 Sep 2007 05:39:45 -0400 (EDT)*References*: <200709050653.CAA26889@smc.vnet.net>

Dear Alex, I confirm that some graphic functions rendering became slower in Mathematic= a 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=B4s a setting to speed the rendering up. Ricardo Samad On 9/5/07, Alex Shvydky <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 Aplica=E7=F5es IPEN/CNEN-SP AV. Prof. Lineu Prestes 2242 Cidade Universit=E1ria 05508-000 S=E3o Paulo - SP Brazil ____________________________________

**References**:**Slow Show/Graphics in v6.0***From:*Alex Shvydky <ashv@lle.rochester.edu>