help in neural network

Hello every one I am try to make neural network to predict permeability in oil field from wireline log so I have 5 input and one target I normaliz data to -1 and 1 but when I train network did not give me good r2 just 0.58 some time 0.62 what I do to reach r2 0.92 Many thanks muhammed

[Greg Heath]

Insufficient info.

 size(input)      [5 N ]
 size(output)      [ 1 N ]
 Type of net       fitnet ??
 range of hidden   Hmin:dH:Hmax ??
 number of random weight trials for each value of H Ntrials ??

Any other non-default parameters??

[muhammed kareem]

thanks dear Greg my input is 5*251 my target is 1*251......... i use newff ...... i do not know how range my hidden and weight>>>>>>>>>>>>>>

this is my code

net = newff(p, t, 20, {'logsig', 'purelin'});

net.divideParam.trainRatio = 75/100;

net.divideParam.testRatio = 15/100;

net.divideParam.valRatio = 10/100;

net.trainParam.epochs = 400;

net.trainParam.goal = 0.000001;

net.trainParam.max_fail = 200;

net.trainParam.lr = 0.06;

[net tr] = train(net,p,t);

a=sim(net,test);

postreg(a,tt);

Answer 1

[Greg Heath]

The optimal value for H is usually obtained by trial and error. For each candidate value for H design Ntrials nets with different random initial weights.

I have posted many, many examples using a double for loop over H and weight initializations. Search NEWSGROUP and ANSWERS for the latest examples using

 greg fitnet Ntrials

If you have the current functions FITNET (regression/curve-fitting)and PATTERNNET(classification/pattern-recognition) that automatically call FEEDFORWARDNET, use them instead of the OBSOLETE functions NEWFIT and NEWPR that automatically call NEWFF.

Hope this helps.

Thank you for formally accepting my answer

Greg