2738 search results for "gis"

Simple network diagrams in R

June 12, 2012
By
Simple network diagrams in R

Why study networks? Development and aid projects these days are more and more often focussing on supporting networks, so tools to analyse networks are always welcome. In this post I am going to present a very easy-to-use package for the stat...

Read more »

Simple network diagrams in R

June 12, 2012
By
Simple network diagrams in R

Why study networks? Development and aid projects these days are more and more often focussing on supporting networks, so tools to analyse networks are always welcome. In this post I am going to present a very easy-to-use package for the stats program R which makes nice-looking graphs of these kinds of networks. In a recent

Read more »

Statistics of Drawdown–paper and post

June 11, 2012
By
Statistics of Drawdown–paper and post

Thank so much to Patrick Burns’ post Variability in maximum drawdown.  He starts with “Maximum drawdown is blazingly variable,” which I say is why money management is so blazingly difficult.  After spending a lot of time thinking about ...

Read more »

Time series cross-validation 4: forecasting the S&P 500

June 11, 2012
By
Time series cross-validation 4: forecasting the S&P 500

I finally got around to publishing my time series cross-validation package to github, and I plan to push it out to CRAN  shortly. You can clone the repo using github for mac, for windows, or linux, and then run the following script to...

Read more »

Simulating Euro 2012

June 11, 2012
By
Simulating Euro 2012

Why settle for just one realisation of this year’s UEFA Euro when you can let the tournament play out 10,000 times in silico? Since I already had some code lying around from my submission to the Kaggle hosted 2010 Take on the Quants challenge, I figured I’d recycle it for the Euro this year. The

Read more »

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...

Read more »

Testing recommender systems in R

June 10, 2012
By
Testing recommender systems in R

Recommender systems are pervasive. You have encountered them while buying a book on barnesandnoble, renting a movie on Netflix, listening to music on Pandora, to finding the bar visit (FourSquare). Saar for Revolution Analytics, had demonstrated how to get started with some techniques for R here. We will build some using Michael Hahsler’s excellent package

Read more »

ggplot2: Creating a custom plot with two different geoms

June 9, 2012
By
ggplot2: Creating a custom plot with two different geoms

This past week for work I had to create some plots to show the max, min, and median of a measure across the levels of a qualitative variable, and show the max and min of the same variable within a … Continue reading →

Read more »

LondonR meeting (June 19th)

June 9, 2012
By

Mango Solutions announces the next LondonR meeting which will take place on June 19th. The meeting is free and open to anyone interested in R.  If you would like to attend please register in advance via email to [email protected] Date:                     Tuesday 19th June 2012 Venue:                 The Counting House, 50 Cornhill, London, London EC3V 3PD (note change of usual...

Read more »

Rcpp vs. R implementation of cosine similarity

June 9, 2012
By

While speeding up some code the other day working on a project with a colleague I ended up trying Rcpp for the first time. I re-implemented the cosine distance function using RcppArmadillo relatively easily using bits and pieces of code I found scattered around the web. But the speed increase was not as much as I expected comparing the...

Read more »