Random Forest

It is basically bagging decision tree. Say we can bootstrap $latex M$ dataset from the original dataset. We then train each bootstrap dataset by a decision tree algorithm, to ensure diversity and reduce complexity, only $latex k \approx \sqrt{d}$ dimensions, where $latex d$ is original dimension. The nice thing of random forest is that it…

Transductive inference

Came across a presentation that mentioned transductive learning (in contrast to inductive learning). I didn’t know this terminology before. Wiki gave a very good introduction. The term was coined by Vapnik in the 90s, where he believes transductive is better. The original term came from psychology. Inductive reasoning came from logic, while transductive reasoning came…

Multi-armed bandits

I always forgot which problem multi-armed bandits actually refer to. I vagulely recalled the one-armed bandit as the slot machine. But I often was confused about that. As a non-native speaker, I first learned the word bandit from playing RPG games as a kid. When I learned that a slot machine can also be referred…

Motivating MCMC

Maybe it is my communications background, it took me long time to really “understand” why we need MCMC. Consider a really simple inference problem of trying to recover state from data , in Bayesian inference, we try to compute the posterior distribution In all textbooks, it will just explain that the denominator is hard to…

Debugging Torch with Zerobrane

I am kind of new to Zerobrane studio and followed this guide to try to debug Torch code. However, I came across with the error attempt to index a nil value (global ‘utils’) for printf = utils.printf It turns out that the path was not setup correctly. In the config file (Edit | Preferences |…

Problem upgrading Tensorflow under Anaconda

I tried to upgrade tensorflow today. I have a virtualenv for version 2 installed under anaconda 3. If I simply run pip install -U tensorflow I got error like Cannot remove entries from nonexistent file /home/user/dummy/anaconda32/envs/tst/lib/site-pack ages/easy-install.pth It turns out that this appears to be a bug from Ananconda, adding “–ignore-installed” seems to be able…