random walk visualization

*To*: mathgroup at smc.vnet.net*Subject*: [mg105245] random walk visualization*From*: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>*Date*: Wed, 25 Nov 2009 02:34:33 -0500 (EST)

Dear Community, I am making a demonstration for a lecture on random walk. This should show the random walk evolving in 2D. The following works nicely: x := 0; y := 0; tab = Table[{x += RandomInteger[{-1, 1}], y += RandomInteger[{-1, 1}]}, {1000}]; imTab = Table[ Show[{Graphics[{Blue, Line[tab[[1 ;; i]]]}], Graphics[{Red, Thick, Arrowheads[0.03], Arrow[{tab[[1]], tab[[i]]}]}]}, PlotRange -> {{-40, 40}, {-40, 40}}], {i, 2, 1000} ]; ListAnimate[imTab] It however, takes a lot of memory, and few minutes to generate the graphics list. That is too long. If I could directly Animate the graphics instead of generating initially a graphics list, it would be much faster. This intends to do such a direct animation: x := 0; y := 0; tab = Table[{x += RandomInteger[{-1, 1}], y += RandomInteger[{-1, 1}]}, {1000}]; Animate[Show[{Graphics[{Blue, Line[tab[[1 ;; i]]]}], Graphics[{Red, Thick, Arrowheads[0.03], Arrow[{tab[[1]], tab[[i]]}]}]}, PlotRange -> {{-40, 40}, {-40, 40}}], {i, 2, 1000} ] But it does not work. I cannot understand the reason. Any idea? Regards, Alexei -- Alexei Boulbitch, Dr., habil. Senior Scientist IEE S.A. ZAE Weiergewan 11, rue Edmond Reuter L-5326 Contern Luxembourg Phone: +352 2454 2566 Fax: +352 2454 3566 Website: www.iee.lu This e-mail may contain trade secrets or privileged, undisclosed or otherwise confidential information. If you are not the intended recipient and have received this e-mail in error, you are hereby notified that any review, copying or distribution of it is strictly prohibited. Please inform us immediately and destroy the original transmittal from your system. Thank you for your co-operation.