Re: Slow Show/Graphics in v6.0

*To*: mathgroup at smc.vnet.net*Subject*: [mg80962] Re: [mg80906] Slow Show/Graphics in v6.0*From*: Alex Shvydky <ashv at lle.rochester.edu>*Date*: Thu, 6 Sep 2007 05:32:04 -0400 (EDT)*References*: <200709050653.CAA26889@smc.vnet.net> <8860260B-096B-4F56-95A1-E2208C4BE319@wolfram.com>

Hello Brett, Thanks for the reply. Do I understand it correctly that you confirm that the new Mathematica v6.0 is upto 100 slower on sertain types of operations compared to v5.0??? Is this a design issue or a simple future patch can fix it? At this point v6.0 is completely unusable for my applications. It is like you would buy a new car that would offer more features and comfort and look fabulous but would have 5 miles per hour maximum speed. You guys should do a better job at this. Alex Brett Champion wrote: > On Sep 5, 2007, at 1:53 AM , Alex Shvydky 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?). > This should be much faster to render, although it's still a bit > sluggish to resize. > > > Timing[Show[ > Graphics[{Hue[0.7], > AbsoluteThickness[ > 0.1], {Line[ > Developer`ToPackedArray[ > N[Flatten[ > Table[{{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}], > 1]]]]}}], > PlotRange -> {{-1, 1}, {0, 1}}, AspectRatio -> 1/2, Axes -> True, > DisplayFunction -> $DisplayFunction, ImageSize -> 800]] > > Brett Champion > Wolfram Research > -- _______________________________________________________________ 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 _______________________________________________________________

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