By design GNU R uses lexical scoping. Fortunately it allows for at least two ways to simulate dynamic scoping.Let us start with the example code and next analyze it:x <- "global"f1 <- function() cat("f1:", x, "\n")f2 <- function() cat("f2:", e...
211 search results for "evaluation"
Automatic Hyperparameter Tuning Methods
At MSR this week, we had two very good talks on algorithmic methods for tuning the hyperparameters of machine learning models. Selecting appropriate settings for hyperparameters is a constant problem in machine learning, which is somewhat surprising given how much expertise the machine learning community has in optimization theory. I suspect there’s interesting psychological and
A weighting function for ‘nls’ / ‘nlsLM’
Standard nonlinear regression assumes homoscedastic data, that is, all response values are distributed normally. In case of heteroscedastic data (i.e. when the variance is dependent on the magnitude of the data), weighting the fit is essential. In nls (or nlsLM of the minpack.lm package), weighting can be conducted by two different methods: 1) by supplying 
2nd CFP: the 10th Australasian Data Mining Conference (AusDM 2012)
The Tenth Australasian Data Mining Conference (AusDM 2012) Sydney, Australia, 5-7 December 2012 http://ausdm12.togaware.com/ The Australasian Data Mining Conference has established itself as the premier Australasian meeting for both practitioners and researchers in data mining. This year’s conference, AusDM’12, co-hosted … Continue reading →
Preview of functional programming syntax for futile.paradigm 2.1
I’m developing a streamlined syntax for the next release of futile.paradigm. While this version is backwards compatible, it introduces a …
Network Visualization of Key Driver Analysis
Whatever happened to those evaluations that your airline asked you to complete after taking a flight? They ask you for a number of ratings about buying your ticket, attributes of the plane, the service you received, and if you were satisfied, if you wo...
Solving mastermind with R
In my last post I have shown a solution to classical sorting problem in R. So I thought that this time it would be nice to generate a strategy for playing Mastermind using R.It was shown by D.E. Knuth that Mastermind code can be bro...
Optimal sorting using rpart
Some time ago I read a nice post Solving easy problems the hard way where linear regression is used to solve an interesting puzzle. Following the idea I used rpart to find optimal decision tree sorting five elements.It is well known that...
Classifying the UCI mushrooms
In my last post, I considered the shifts in two interestingness measures as possible tools for selecting variables in classification problems. Specifically, I considered the Gini and Shannon interestingness measures applied to the 22 categorical mushroom characteristics from the UCI mushroom dataset. The proposed variable selection strategy was to compare these values when computed from only edible mushrooms...
Evaluation of Tactical Approaches
Tactical approaches are often chosen based on the best cumulative return which implicitly incorporates significant hindsight bias. Just because an approach dominates for a period of time does not indicate that it will be the best approach. ...
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
