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Greg Heath <heath@alumni.brown.edu> wrote in message <f88c4240-7211-4544-9ca1-f5a6568454cf@f20g2000vbl.googlegroups.com>...
> On Nov 19, 1:36 am, "aurikel Radzali" <suriar...@gmail.com> wrote:
> > Greg Heath <he...@alumni.brown.edu> wrote in message <9bfd2ece-92b5-432f-a82c-61238af4d...@j4g2000yqe.googlegroups.com>...
> > > On Nov 16, 4:23 am, "aurikel Radzali" <suriar...@gmail.com> wrote:
> > > > GregHeath<he...@alumni.brown.edu> wrote in message <dc9ef436-338f-40fb-aa39-d679e47f6...@j11g2000vbi.googlegroups.com>...
> > > > > On Nov 15, 9:15?pm, "aurikel Radzali" <suriar...@gmail.com> wrote:
> > > > > > Hi, I am working on radial basis network to predict protein conc.
> Part of the task is to compare result between newrb & newrbe. I have
> no
> problem with the newrb but for newrbe I got this warning:
> >
> > > > > > Warning: Rank deficient, rank = 5, ?tol = ? 2.7195e-014.
> > > > > > ?> ?In newrbe>designrbe at 122
> > > > > > ? ? ?In newrbe at 105
> > > > > > ? ? ?In RBFnormBnewrbe01_VCC_TRAINOPTIMIZE at 64
> >
> > > > > > 1.below are my source (newrbe):
> >
> > > > > > K=TRAINOPTIMIZE;
> > > > > > [r,c]=size(K);
> >
> > > > > > GOAL=0.5;%SPREAD=input
> > > > > > SPREAD=20;
> > > > > > MN=24; % sample points
> > > > > > DF=1;
> > > > > > %net.layers{1}.transferFcn='radbas';
> > > > > > %net.layers{2}.transferFcn='purelin';
> >
> > > > > > net=newrbe(P,T,SPREAD);
> > > > > > Y=sim(net,P);
> >
> > > > > > 2.below are my source (newrb):
> >
> > > > > > GOAL=0.5; %SPREAD=input
> > > > > > SPREAD=20;
> > > > > > MN=24; % sample points
> > > > > > DF=1;
> > > > > > %net.layers{1}.transferFcn='radbas';
> > > > > > %net.layers{2}.transferFcn='purelin';
> >
> > > > > > net=newrb(P,T,GOAL,SPREAD);
> > > > > > Y=sim(net,P);
> >
> > > > > > note: i got the result as follow:
> > > > > > NEWRB, neurons = 0, MSE = 0.130203
> >
> > > > > > where i could be wrong?or did i miss something important?
> >
> > > > > You say "I have no problem with the newrb".
> > > > > However, you report "neurons = 0, MSE = 0.130203"
> >
> > > > > which makes no sense to me. Furthermore, the value 0.13
> > > > > means nothing unless it is compared to a reference.
> > > > > What is mean(var(T))?
> >
> > > > >Greg
> >
> > > > Hi, actually i have a problem with newrb too except
> > > > it does not produce warning like the newrbe.
> >
> > > > --> this is the newrb code:
> >
> > > size(P) = ?
> > > minmax(P) = ?
> > > size(T) = ?
> > > minmax(T) = ?
>
>
> Please answer the questions.
---->size(P) =3 24
size(T) =1 24
>
> > > > GOAL=0.5;
> >
> > > Note: In my version 6.5 this is SSEgoal, NOT MSEgoal;
>
> > -----------> I just put random value, I do not know what
> > value should i choose.
>
> > > Why did you choose this value?
> >
> > > For the best constant model y = mean of targets:
> >
> > > y00 = repmat(mean(T,2),1,size(T,2));
> > > e00 = T-y00;
> > > SSE00 = sse(e00)
> >
> > > For newrb, it is desirable to have
> >
> > > SSEgoal < SSE00/100
> >
> > > so that
> >
> > > R^2 = 1-SSE/SSE00 > 0.99
>
> > -----------> i do not understand, what is the purpose of this?
>
> R^2 (coefficient of determination) is a measure of the
> fraction of output variance that is represented by the model.
> See any statistic book that covers regression.
>
> http://en.wikipedia.org/wiki/Coefficient_of_determination
>
> > > > SPREAD=5;
> >
> > > Why did you choose this value?
>
> > ------------------> i just put some value, i don't know what
> values should i use? (i thought the best spread is obtained
> > through trial and error method)
>
> True, but why whistle in the dark when you can quickly estimate
> a few charcteristic distances to help limit the search?
>
------------------>how do i estimate characteristic distances to help limit the search? i even do not know what no should i start with.
> > > How does it compare to
> >
> > > 0.5*mean(median(dist(P,P')))?
>
> Typical half-distance between data points. More useful
> when the data points are either cluster centers from a previous
> cluster analysis or data points selected as neurons.
>
> > ---------> do you mean compare this and spread=5?
>
> Yes.
>
> > ------------->btw, 0.5*mean(median(dist(P,P')))=1.0815
-----------> is this some kind of guideline to choose the spread? the spread should be around that value, it is?less or more but not too far away?
> What is it for hidden neurons ?
>
> > > > MN=24; % sample points
> > > > DF=1;
> >
> > > > %net.layers{1}.transferFcn='radbas';
> > > > %net.layers{2}.transferFcn='purelin';
> >
> > > > net=newrb(P,T,GOAL,SPREAD);
> >
> > > [net, tr] = newrb(P,T,GOAL,SPREAD);
> >
> > -----------------> what is the different between the those two?
> >What is the purpose of putting [net,tr]?
>
> tr is the training record
>
> help newrb
> doc newrb
>
> > > > Y=sim(net,P);
> > > > e=T-Y;
> > > > msetrain=mse(e)
> >
> > > compare with tr.perf(end)
>
> > --------------tr.perf(end)=0.0018
>
> > > > --> this is the result:
> > > > NEWRB, neurons = 0, MSE = 0.130203
> >
> > > If N ~ 24, This is not inconsistent with
> > > mean(var(T)) = 0.1359.
>
> > ___________> I'm really sorry, but i truly do not
> understand what do you by If N ~ 24,
> This is not inconsistent with mean(var(T)) = 0.1359
> >
> > ----------------------->how it suppose to be??
>
> If neurons = 0. Then the the output is a constant
> equal to the bias. To minimize SSE, the constant must
> be mean(T). The resulting MSE is (N-1)*var(T)/N
>
---------->forgive me, i still don't understand.
mean(T)=0.5389
mean(var(T)) = 0.1359
MSE i= (N-1)*var(T)/N= 0.1302 so?
--->To minimize SSE, 'the constant' must be mean(T). 'the constant' refer to?
> > > Where is the tabulation for neurons > 0?
> >
> > > > msetrain =
> >
> > > > 0.0018
> >
> > > For how many neurons?
> > > -------------->Number of nodes in hidden layer=2.0000e+000
> >
> > > > why the mse value is different?
> >
> > > Different number of neurons
> > > What is tr.epoch(end)?
> > > ---------> 2
> > > >the mean(var(T)) is 0.1359
> >
> > > MSE(neurons = 0) = (N-1)*mean(var(T'))/N
> > > -------------> owhh..thats why i get the MSE=0.1302
> > > Hope this helps.
> >
> > > Greg
> >
> > ==============> Thanks, I still have some questions.
> >
> > based on your advice, %For newrb, it is desirable to have SSEgoal < SSE00/100
> > SSE00=3.1249
> > SSEm=SSE00/100 %produce 0.0312
> >
> > so i choose my goal 0.0005 % since SSEgoal < SSE00/100. is this right?
>
> I would use 0.02.
>
> Hope this helps.
>
> Greg
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