Blog Archives

Tikz Nodes

October 17, 2011
By
Tikz Nodes

Nodes are used in tikz to place content in a picture as part of a LaTeX document. Fast Tube by Casper When creating a tikz picture the origin is assumed to be at (0,0) and objects are placed with positioning relative to the origin on the picture. If we wanted to add a grid with

Read more »

Tikz Introduction

September 27, 2011
By
Tikz Introduction

The pgf drawing package for LaTeX provides facilities for drawing simple of complicated pictures within a LaTeX document. There are many options available within the package and in this post we consider some of the basics to get up and running. Fast Tube by Casper As with all LaTeX documents we need to select a

Read more »

Cricket All Round Performances

September 19, 2011
By

In cricket a player who can perform well with both the bat and bowl is a great asset for any team and across the history of international cricket there have been a number of cricketers that hall into this bracket. It is difficult to specify a set of criteria to determine whether a player can

Read more »

Scatter plots with images

September 4, 2011
By

Edward Tufte has written extensively on the presentation of data covering good and bad practice. He has made a number of suggestions for adaptations of regularly used graph types to assist with the interpretation and understanding of data. One idea for enhancing scatter plots covered in Tufte’s book Beautiful Evidence is the use of images

Read more »

LaTeX Typesetting –Basic Mathematics

August 1, 2011
By
LaTeX Typesetting –Basic Mathematics

LaTeX is very strong for typesetting mathematical equations. Fast Tube by Casper Other useful resources are provided on the Supplementary Material page.

Read more »

Getting rid of white space at the beginning and end of a string

July 28, 2011
By

There are situations where we are working with character strings extracted from various sources and it can be annoying when there is white space at the beginning and/or end of the strings. This whitespace can cause problems when attemping to sort, subset or various other common operations. The stringr package has a handy function str_trim

Read more »

R.NET

July 4, 2011
By

The R.NET project provides a mechanism for communicating with R from a .NET application. This appears to be a promising way to create simple interfaces to some of the functionality of R. Some examples of using R.NET can be found here and here.

Read more »

Generalized Linear Models – Poisson Regression

June 26, 2011
By
Generalized Linear Models – Poisson Regression

The Generalized Linear Model (GLM) allows us to model responses with distributions other than the Normal distribution, which is one of the assumptions underlying linear regression as used in many cases. When data is counts of events (or items) then a discrete distribution is more appropriate is usually more appropriate than approximating with a continuous

Read more »

Handling Errors Gracefully

May 27, 2011
By

In R functions sometimes produces warnings or errors. In the case of errors execution of a function or a series of commands can get halted when an error occurs, which can in some cases be frustrating especially if we want to continue our calculations. There are various functions available in R for dealing with errors

Read more »

Fractional Factorial Designs using FrF2

May 18, 2011
By

The FrF2 package for R can be used to create regular and non-regular Fractional Factorial 2-level designs. It is reasonably straightforward to use. First step is to install the package then make it available for use in the current session: require(FrF2) A basic call to the main functino FrF2 specifies the number of runs in

Read more »