Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
Drexel University or The Math Forum.



Re: Could someone help optimize this for Mathematica 9?
Posted:
Dec 5, 2012 3:11 AM


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[mStopTimemStartTime]] > > 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 453420312 USA > Paul.McHale@Excelitas.com > www.excelitas.com > > > >



