How many times should I re-train my images in nprtool ?

1 view (last 30 days)
Explorer
Explorer on 15 Feb 2014
Commented: chun hu on 13 Jun 2017
What should be the range of results (e.g Target MSE)?

Accepted Answer

Greg Heath
Greg Heath on 16 Feb 2014
Edited: Greg Heath on 17 Feb 2014
Data = Designdata + Testdata
Designdata = Trainingdata + Validationdata % Performance estimates are BIASED
If the data set is sufficiently large, a classifier should be chosen on the basis of the BIASED (but non-training) Validationdata error rate (%E). An un-biased evaluation can then be obtained on the basis of the UNBIASED non-design Testdata error rate. The uncertainty of error rate estimates for a sufficiently large data set is inversely proportional to it's size. If the data set is small, repeat the design multiple times so that the number of hidden nodes is minimized and each input vector has many chances to be in each of the three data subsets. It may also be wise to add a little random error to each vector.
A data set size of N = 6 does not provide enough information for a real world problem. You might want to use cross validation with the 6*5/2 =15 combinations of val/test data combinations and/or add noisy duplicates to improve the ability of the nets to perform on unseen data.
This is best done using a loop in a command line program.
Hope this helps.
Thank you for formally accepting my answer
Greg

More Answers (1)

smriti garg
smriti garg on 23 Oct 2015
Hello sir,
I have one doubt regarding nprtool use. I have generated advanced script of nprtool and want to implement it by some property changes. On running the program, I got the trained 'net' ANN model. My question is that I want to retrain this 'net' multiple times to get better model. Can I do This..? If yes..then how...?
Please give some suggestions.
Thanks in advance...

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by