My completely unfounded guess would be the sign is built into gradientBase On Nov 28, 2012, at 2:19 PM, David Kincaid wrote:
> While trying to wrap my head around the Mahout code for SGD I noticed that > the update to the beta terms seems to be doing gradient ascent and not > descent. Could someone help me find the missing minus sign? > > The line of code in question from AbstractOnlineLogisticRegression.java, > train() is: > > double newValue = beta.getQuick(i, j) + gradientBase * learningRate > * perTermLearningRate(j) * instance.get(j); > > It looks to me like the update to beta is ascending the gradient (hence the > addition sign instead of minus). Could you help me understand where my > thinking is going wrong? > > Thanks, > > Dave
