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Multilayer Perceptron (backprop) ANN quesion

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#1
ibad

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OK..some very basic questions here... so please indulge me

Firsly.... the delta W that is computed for each weight... it is simply added to it right? The delta rule takes care of the sign I am assuming?

second: the weights can be negative or positive right?

Thanks!!

#2
WingedPanther

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You'll have to provide a little more context before anyone is likely to be able to answer your question.
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#3
ibad

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Ok..context....

delta W is delta-weight... the change in weight...calculated with the delta rule.

I am using sigmoid function neurons, it's a simple MLP with each layer fully connected to the next one. It's going to be used for letter recognition (very simple OCR).

The net is shown a 32x32 graphic file which has a black and white charcter in it from a to b (lower case).

It is feed-forward. erm....what else... yeah the outputs are binary encoded. 7 output neurons, so the output is supposed to be ascii.. output neurons are also sigmoid. Any output value above 0.9 is considered a 1, any below 0.1 is considered a zero.

And... the weights are reals, well doubles ... supposed to simulated real valued weights. So I am asking if the weights can be negative or not (I am a beginner...so this might be very simple for you).

I am also asking if the delta-W that is calculated with the delta rule produces is already sign corrected... in which case it is simply added to the current weight that is being adjusted.

I am thinking that the answer to both questions is yes..the weights can be negative, and the delta-W is just added... but I don't really have any guidance, am teaching myself... so I just wanted to be sure.

#4
WingedPanther

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I'm thinking the same thing, but haven't done any work on Perceptron's (or neural nets).
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#5
Predictor

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ibad said:

OK..some very basic questions here... so please indulge me

Firsly.... the delta W that is computed for each weight... it is simply added to it right? The delta rule takes care of the sign I am assuming?

second: the weights can be negative or positive right?


Yes and yes.