List concatenation speed
- To: mathgroup at smc.vnet.net
- Subject: [mg87571] List concatenation speed
- From: carlos at Colorado.EDU
- Date: Sun, 13 Apr 2008 03:32:46 -0400 (EDT)
I am building mesh plots that require concatenation of thousands of Graphics objects into one list for Show[]. This is done by appending objects as they are created, and there are several ways to do that. Tested 3 of them for speed using a simple object: p=Table[x,{50}]; n=10000; ClearAll[poly]; poly={}; Print[Timing[Do[AppendTo[poly,p],{i,1,n}]]]; ClearAll[poly]; poly={}; Print[Timing[Do[poly=Append[poly,p],{i,1,n}]]]; ClearAll[poly]; poly={}; Print[Timing[Do[poly=Join[poly,{p}],{i,1,n}]]]; {5.8395 Second,Null} {5.7206 Second,Null} {6.29728 Second,Null} Tests were run on version 5.2 on a G5 desktop Mac. I expected Join to win, but it didnt. Is there a faster way?
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- From: János <janos.lobb@yale.edu>
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