A year ago I wrote a post on speeding up R computations. Some of the tips that I mentioned then have since been made redundant by a single package: compiler. Forget about worrying about curly brackets and whether to write 3*3 or 3^2 - compile...
Monthly Archives: April 2012
Create polygons from a matrix
The following function matrix.poly allows for the addition of polygons to a plot based on a matrix and defined matrix positions. I have used this function on occasion to highlight specific matrix locations (e.g. in the above figure). You can do the same by overlaying another image (left in above plot) but with this...
Read Big Text Files Column by Column
Dear R Programmers,There is new package "colbycol" on CRAN, which makes our jobs easier when we have large files i.e. more than a GB to be read in R. Especially, when we don't need all of the columns/variables for our analysis. Kudos for author, Carlos...
Graphic Parameters (symbols, line types, and colors) for ggplot2
Following up on John Mount’s post on remembering symbol parameters in ggplot2, I decided to give it a try and included symbols, line types, and colors (based upon Earl Glynn’s wonderful color chart). Code follows below. require(ggplot2) ...
Graphic Parameters (symbols, line types, and colors) for ggplot2
Following up on John Mount’s post on remembering symbol parameters in ggplot2, I decided to give it a try and included symbols, line types, and colors (based upon Earl Glynn’s wonderful color chart). Code follows below. require(ggplot2) ...
Randomization thoughts
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| Le Grand Casino of Monte Carlo |
soilDB Demo: Processing SSURGO Attribute Data with SDA_query()
Mapping near Paloma, CA This image has nothing to do with the following content. A quick example of how to use the USDA-NRCS soil data access query facility (SDA), via the soilDB package for R. The following code describes how to get component-level so...
AdfTest Function Enhanced With Rcpp Armadillo
In my previous post about rewriting my code to run in parallel part one I mentioned that we will make a small change to adfTest() function as well. In this post we will perform this small but performance-dramatic change. When you take a closer look at the source code of this particular function from fUnitRoots package
Structural Breaks (Bull or Bear?)
When I spotted the bfast R package, I could not resist attempting to apply it to identify bull and bear markets. For all the details that I do not understand, please see the references: Jan Verbesselt, Rob Hyndman, Glenn Newnham, Darius Culvenor...
Graphic Parameters (symbols, line types, and colors) for ggplot2
Following up on John Mount’s post on remembering symbol parameters in ggplot2, I decided to give it a try and included symbols, line types, and colors (based upon Earl Glynn’s wonderful color chart). Code follows below.
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
