How do validation check work in Neuralnet ?

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R G 2017-8-7

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评论： Moritz Hesse 2019-5-2

I'm learning about the neural network in MATLAB. when I learn about the neural net, I don't see anything about validation check (usually data is divided by 2 training and test testing) but in Matlab, they have a part for validation and have Validation check(in figure = 6).

so what I want to know is why we need validation check and how it work to check

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Greg Heath 2017-8-7

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编辑：Greg Heath 2018-7-11

design = train + validate

train : Weight Estimation

validate: Not directly involved in weight estimation. Protects ability to generalize to nontraining data. Stops training when the nontraining val subset error rate increases CONTINUOUSLY for more than 6 (default) epochs.

val subset error rate is therefore SLIGHTLY biased.

test subset error rate is COMPLETELY unbiased

default division ratio = 0.7/0.15/0.15

If val stopping occurs, take a look at the error rate curves and you will see why training was stopped.

OBVIOUSLY, the most unbiased approach for constant timestep timeseries prediction is to use DIVIDEBLOCK data division with the validation subset in the middle.

Hope this helps

Thank you for formally accepting my answer

Greg

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Greg Heath 2018-7-11

编辑：Greg Heath 2018-7-11

Thanks for the heads up! Changed to:

OBVIOUSLY, the most UNBIASED approach for constant timestep timeseries prediction is to use DIVIDEBLOCK data division with the validation subset in the middle.

GREG