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Old 05-04-2013, 11:10 AM
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yaser yaser is offline
Join Date: Aug 2009
Location: Pasadena, California, USA
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Default Re: Basic logistic regression question

Originally Posted by arcticblue View Post
From lecture 9 page 23 of the slides there is an algorithm of how to implement logistic regression. In step 3 it explains how to compute the gradient. Is the E-in value actually a vector or is it a single number? If it's a single number then the weight would be the same for every value in the weight vector so it seems like E-in is a vector. Is my understanding correct?
E_{\rm in} is a scalar quantity whose value depends on the entire vector of weights {\bf w}. Step 3 computes the gradient, which is a vector of derivatives of E_{\rm in} with respect to each of those weights, so each component of the gradient vector is the derivative with respect to a different weight
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