Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2009

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Slow performance gathering property data from fitted

  • To: mathgroup at smc.vnet.net
  • Subject: [mg101022] Re: [mg101013] Slow performance gathering property data from fitted
  • From: DrMajorBob <btreat1 at austin.rr.com>
  • Date: Sun, 21 Jun 2009 07:05:22 -0400 (EDT)
  • References: <200906200803.EAA16775@smc.vnet.net>
  • Reply-to: drmajorbob at bigfoot.com

Did you do something equivalent to this?

data := Table[{3 + i + RandomReal[{-3, 7}],
    i + RandomReal[{-2, 5}]}, {i, 1, 20}]

Timing[models = Array[LinearModelFit[data, x, x] &, 70000];]

{90.2283, Null}

Timing[rsquares = Through[models@"RSquared"];]

{40.3059, Null}

ListPlot@rsquares

Notice, the RSquare values came out faster than the model fitting.

Bobby

On Sat, 20 Jun 2009 03:03:15 -0500, Todd Allen <genesplicer28 at yahoo.com>  
wrote:

>
> Hi All,
>
>    During some recent research I asked Mathematica to calculate 70,000  
> simple linear regression fits to 70,000 small datasets.  This worked  
> well and resulted in a list of 70,000 fitted model objects being  
> finished in under 5 minutes.
>
>   My next step was to collect the RSquared property for each of the  
> 70,000 fits contained in the list, and Mathematica took over 3 hours to  
> accomplish this.  This seems horrendously slow simply to gather values  
> from a list.  Has anyone ran into a similar problem?  Any suggestions  
> how I might be able to significantly speed the gathering of properties  
> from large lists of fitted model objects?
>
>
>   The snippet of code I was using to gather the RSquared values is below:
>
> piedlrRsquared =
>   Table[piedlrmodels[[i]]["RSquared"], {i, 1, Length[piedlrmodels]}] //
>     Timing;
>
>
>    Thanks for any advice you might have!
>
> Todd
>
>
>



-- 
DrMajorBob at bigfoot.com


  • Prev by Date: When to use Module inside Manipulate
  • Next by Date: laptop recommendation to run mathematica fast?
  • Previous by thread: Slow performance gathering property data from fitted objects
  • Next by thread: Re: Slow performance gathering property data from fitted