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Old 05-06-2013, 07:35 PM
Ziad Hatahet Ziad Hatahet is offline
Join Date: Apr 2013
Location: San Francisco, CA
Posts: 23
Default HW5 Q9: SGD and Epochs?

I think I may be missing something concerning SGD. The description of the problems for Logistic Regression states that: An epoch is a full pass through the N data points.

Does that mean that each of the given answers corresponds to 100x the number iterations (e.g. answer [a] is 350, so we make 3,500 iterations before converging?)

The way I am currently implementing SGD is as follows (pseudo-code):
for each trial {
  generate N points, with corresponding target function and Y
  set weight vector to |0|
  while true {
    pick random point xn, and corresponding yn
    calculate e = -yn*xn/(1 + exp(yn*wt*xn)
    w(t+1) = w(t) - learning_rate*e
    break if ||w(t+1) - w(t)|| < tolerance
  use weight vector to calculate Eout = E[ln(1 + exp(-Y*w*X)], for M new points, and find the mean Eout
In this case, I am taking the mean of the number of iterations in the inner while loop as the answer for Q9. Am I doing something wrong?

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