Re: Could someone help optimize this for Mathematica 9?

*To*: mathgroup at smc.vnet.net*Subject*: [mg128954] Re: Could someone help optimize this for Mathematica 9?*From*: Christoph Lhotka <christoph.lhotka at fundp.ac.be>*Date*: Wed, 5 Dec 2012 03:15:18 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net*References*: <20121204091410.B2B8E68C4@smc.vnet.net>

Dear Paul, I did not investigate the issue further but I have the feeling that it has to do something with packed arrays: I get a speed up of a factor of 6.5 if I change your code into (I just add a '.' after 100000 and 10): mNumberSamples = 100000.; mFrequency = 10.; m = Table[{t/mNumberSamples, Sin[t/mNumberSamples mFrequency*2 \[Pi]]}*1.0, {t, 1, mNumberSamples}]; mStartTime = SessionTime[]; ListLinePlot[m] mStopTime = SessionTime[]; StringForm["Elapsed time = ``", N[mStopTime - mStartTime]] If you try your original code Developer`PackedArrayQ[m] returns False while in my modified code Developer`PackedArrayQ[m] returns True. So I guess that ListLinePlot works faster with packed arrays. Best, Christoph On 12/04/2012 10:14 AM, McHale, Paul wrote: > We have a strong need to view large numbers of data points. Mathematica 8 was excellent at this. The following code executed under both 8 and 9 (Windows): > > Mathematica 8: Less than 0.5 seconds > Mathematica 9: Greater than 4 seconds > > mNumberSamples=100000; > mFrequency=10; > m=Table[{t/mNumberSamples ,Sin[t/mNumberSamples mFrequency*2 \[Pi]]}*1.0,{t,1,mNumberSamples}];mStartTime=SessionTime[]; > ListLinePlot[m] > mStopTime=SessionTime[]; > StringForm["Elapsed time = ``", N[mStopTime-mStartTime]] > > I have tried the code on a slower mac laptop (version 9 only) and had the same slower results. Any input welcome as this functionality is extremely important to us. > > > Paul McHale | Electrical Engineer, Energetics Systems | Excelitas Technologies Corp. > > > > > > Phone: +1 937.865.3004 | Fax: +1 937.865.5170 | Mobile: +1 937.371.2828 > 1100 Vanguard Blvd, Miamisburg, Ohio 45342-0312 USA > Paul.McHale at Excelitas.com > www.excelitas.com > > > >

**References**:**Could someone help optimize this for Mathematica 9?***From:*"McHale, Paul" <Paul.McHale@excelitas.com>