Re: Slow performance gathering property data from fitted
- To: mathgroup at smc.vnet.net
- Subject: [mg101033] Re: [mg101013] Slow performance gathering property data from fitted
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sun, 21 Jun 2009 07:07:33 -0400 (EDT)
- Reply-to: hanlonr at cox.net
Don't use Table
data = {{0, 1}, {1, 0}, {3, 2}, {5, 4}};
lm = LinearModelFit[data, x, x];
piedlrmodels = Table[lm, {10000}];
(piedlrRsquared =
Table[piedlrmodels[[i]]["RSquared"], {i, 1,
Length[piedlrmodels]}]); // Timing
{15.5082,Null}
(piedlrRsquared2 = (#["RSquared"] & /@ piedlrmodels)); // Timing
{6.09562,Null}
piedlrRsquared == piedlrRsquared2
True
(%%/%%%)[[1]]
0.393057
Bob Hanlon
---- 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