MLHEP 2015 lectures slides
At the end of this August our team from Yandex organized MLHEP 2015 - summer school on Machine Learning in High Energy Physics.
The school lasted only for 4 days, but even in this little time we managed to teach many things.
The school consisted of two tracks: introductory and advanced, every day each track has 2 lectures + 2 practical seminars. Also, each evening there was a special physics talk by invited speakers from CERN.
No, this is not everything: we organized an inclass kaggle competition based on the COMET tracking problem I wrote about (part 1, part 2), so participants played with ML methods on a real-world problem.
I gave lectures on the introductory track. This was really challenging - to put the course of ML in 4 days to people who have no experience in ML and have different backgrounds (while the major part of introductory track listeners were particle physicists, but this was not very helpful).
One more caveat: since the schedule was completely filled, we decided to give no tasks (and thus all the theoretical knowledge will be obtained from slides).
For this purpose I decided to minimize the number of things introduced in course. The only non-trivial notion I used was decision function. No $F(x)$, no $h_i(x)$, no $Q(x, y)$, no margins, no $\Theta$, no $C(Y, F)$ and other stuff.
Despite these limitations, course contained all the ‘starter kit’ and even more:
- knn
- optimal bayesian classifier, QDA
- logistic regression
- neural networks
- decision trees, building, splitting criterions
- estimating feature importance
- overfitting
- ensembles, bagging
- Random Forest
- comparison of multidimensional distributions
- AdaBoost
- Gradient Boosting, modifications for regression, classification, ranking
- Boosting to uniformity (uBoost and FlatnessLoss)
- Fast predictions for online trigger systems (Bonsai BDT)
- reweighting, Gradient Boosted reweighting
- hyper-parameters optimization, Gaussian Processes
- using classifiers’ output to test physical hypotheses
- unsupervised ML: PCA, autoencoders
Also I significantly reduced number of formulas and added different demonstrations of how different algorithms work.
This is really a lot for introductory 4-days course, but I like this density of ideas.
Gradient boosting
Hamiltonian MC
Gradient boosting
Reconstructing pictures
Neural Networks