Articles by Aviad Klein

Cost Weighted Logistic Loss

December 15, 2016 | 0 Comments

The problem of weighting the type 1,2 errors on binary classification came up in a forum I visit. My solution: Here we can see the different loss behaviours We will try to classify the Virginica species from the iris dataset   And now the loss functions:
[Read more...]

Vertica and R quickie – group_concat transform function

June 23, 2014 | 0 Comments

I’m guessing you can do this in C++, but hey… it works for me. You’ll notice 3 functions that need to be created, the main function which will be called from Vertica, the params functions which is optional and holds the config of parameters optionally pased to the function. ... [Read more...]

R and Vertica

June 14, 2014 | 0 Comments

I’ve been spending the last few months working my way through the integration of R and Vertica, and will try to keep here things that I find handy. I’m quite sad to see there is not much about this Vertica feature on the web, that’s a little ... [Read more...]

A note about the estimating the number of visits to a site

October 21, 2013 | 0 Comments

Motivation How many times do users visit your site? A very relevant question in web analysis. One major issue that biases your estimation is the users who save no cookies, these users change their ID on every page visit so they look like 1 time visitors and thus inflate the proportion ... [Read more...]

An example of linear discriminant analysis

January 8, 2011 | 0 Comments

The following example was shown in an advanced statistics seminar held in tel aviv. The material for the presentation comes from C.M Bishop’s book : Pattern Recognition and Machine Learning by Springer(2006). One way of separating 2 categories using linear sub spaces of the input space (e.g. planes for 3... [Read more...]

Finding out (fast) the classes of data.frame vectors

August 6, 2010 | 0 Comments

Sometimes it’s useful to write down the various classes of vectors inside your data.frame objects for documentation and other people to use it. I’ve searched for a quick way to find out all the classes of vectors inside a data.frame. Since I’ve found no reference ... [Read more...]

Color choosing in R made easy

May 21, 2010 | 0 Comments

I don’t know about you, but when I want to make a graph in R, I handpick the colors, line widths etc… to produce awesome output. A lot of my time is spent on color choosing, I had to find a more convenient way of doing so. Earl F. ... [Read more...]

Never miss an update!
Subscribe to R-bloggers to receive
e-mails with the latest R posts.
(You will not see this message again.)

Click here to close (This popup will not appear again)