LFD Book Forum Question on Gradient
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#1
02-09-2013, 09:27 AM
 melipone Senior Member Join Date: Jan 2013 Posts: 72

For gradient descent in Q5-6, is the gradient a vector consisting of the partial derivatives wrt u and the partial derivative wrt v or is it the derivative wrt to both u and v?
#2
02-09-2013, 09:57 AM
 kartikeya_t@yahoo.com Member Join Date: Jul 2012 Posts: 17

It is the former, i.e., a vector whose first component is the partial derivative of E wrt u, and the second component is the partial derivative of E wrt v.
#3
02-09-2013, 10:56 AM
 melipone Senior Member Join Date: Jan 2013 Posts: 72

Got it!
I have another question: Are you supposed to update the value of the point after updating the weights? I don't see that in the algorithm on p. 95.
#4
02-09-2013, 01:38 PM
 yaser Caltech Join Date: Aug 2009 Location: Pasadena, California, USA Posts: 1,478

Quote:
 Originally Posted by melipone Got it! I have another question: Are you supposed to update the value of the point after updating the weights? I don't see that in the algorithm on p. 95.
In this specific problem, the "weights" are , namely the parameters you are optimizing with respect to.
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#5
02-09-2013, 03:33 PM
 melipone Senior Member Join Date: Jan 2013 Posts: 72

ah, the point (u,v) = (1,1) is the initial weight?
#6
02-09-2013, 07:22 PM
 butterscotch Caltech Join Date: Jan 2013 Posts: 43

you are right!

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