posted
Sorry to come here asking for homework help, but I have a problem that I'm stuck on and I thought that there might be a decent chance that someone here might know the answer (although asking sooner probably would have been a good idea )
Anyways, an exercise for one of my classes involves using a neural network. I've been running into a problem when I use a more than 30 or so nodes in the hidden layer. Basically, if I'm understanding things correctly, calculating the new weight for nodes involves taking the derivative of sigmoid function for the sum of the weighted inputs to that node. If I have a lot of hidden nodes, this sum tends to be fairly big, so the sigmoid' tends to be really really tiny, so the weight pretty much doesn't change.
Does anyone understand what I'm doing wrong here?
Posts: 2437 | Registered: Apr 2005
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posted
Nope. I've heard of neural networks, but never really studied them. My friend back at IU did some stuff with them, but he's not on right now for me to point your way. When is this due?
Posts: 3295 | Registered: Jun 2004
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posted
tomorrow. Hatrack was kind of a desperation measure . If I had more time, I'd probably have asked one of the TAs or something of that nature.
Edit: The good news is that it has worked in some cases, and when it did it got decent results. Or at least around 95-97%is accuracy. It just seems to break down when I use a lot of hidden nodes, and I can't help but think that I it is because my understanding is wrong in some fashion.
Posts: 2437 | Registered: Apr 2005
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posted
Huh. Yeah, can't help you. Wikipedia? It usually has much clearer explanations for thing than text books in my experience. (ironic that...)
Posts: 3295 | Registered: Jun 2004
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posted
Fugu would know, but he has an "I'm asleep" away message up on AIM right now. Then again, he's not idle... can't hurt to try.
Posts: 3295 | Registered: Jun 2004
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posted
In this case, my textbook has a pretty good explaination (or at least about as good as I've found online anywhere). I think I'm just understanding something wrong. It's one of those things where one or two questions directed at someone who knows what they are talking about could hopefully clear things up, except that this problem didn't show up until it was too late to find someone.
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