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MathGroup Archive 2003

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Report using Fit

  • To: mathgroup at smc.vnet.net
  • Subject: [mg44283] Report using Fit
  • From: YAT <yat at omrf.ouhsc.edu>
  • Date: Tue, 4 Nov 2003 03:23:55 -0500 (EST)
  • Reply-to: yat at omrf.ouhsc.edu
  • Sender: owner-wri-mathgroup at wolfram.com

Hi all,
Despite the documentation, does anyone know if Fit can give best fit 
parameters as Regress does? The reason I ask is that, Fit is a lot 
faster than Regress if you have large volumes of data to deal with. 
Regress slows down because (I assume) it is generating the "pretty" 
output. Is there another way of getting at the output of Regress 
(perhaps) before formatting via RegressionReport. Below is an example.

Yas

In[668]:=
Clear[b,nr,nc,ns,nv,syndat,a0,gt1,gt2]

In[650]:=
b={0.1,0.2,0.3};
nr=4;
nc=4;
ns=5;
nv=Length[b];
syndat=Range[nr*nc*ns*nv];
a0=nr*nc*ns;

In[657]:=
yVals=Transpose[Partition[syndat,a0]];
model={1,x};
var=x;
parms=RegressionReport\[Rule]BestFit;

gt1=Table[{{b,yVals[[i]]}//Transpose,model,var},{i,1,a0,1}]//Transpose;

In[662]:=
hmm=MapThread[Fit,gt];//Timing

Out[662]=
{0.03 Second,Null}

In[666]:=
gt2=Table[{{b,yVals[[i]]}//Transpose,model,var,parms},{i,1,a0,1}]//Transpose;
doublehmm=MapThread[Regress,gt];//Timing

Out[667]=
{1.21 Second,Null}



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