The 18th Euler problem is sorta a route finding problem. It has occupied my mind for two days. Finally I came up to a clever solution. Find the maximum total from top to bottom of the triangle below: 75 95 64 17 … Continue reading → [Read more...]

I am often found in possession of palaeo core data where the sample identifiers contain a core code or label plus the sample depth. Often these are things generated by colleagues who have used other software where for one reason … Continue reading → [Read more...]

To estimate if a certain vector of numbers will fit into memory, you can quite easily predict the memory usage based on the size of the vector. An integer vector will use 4 bytes per number, and a numeric vector… See more › [Read more...]

As I have mentioned previously, I have begun reading Statistical Methods in Bioinformatics by Ewens and Grant and working selected problems for each chapter. In this post, I will give my solution to two problems. The first problem is pretty straightforward. Problem 2.20 Suppose that a parent of genetic type Mm ... [Read more...]

R is my favorite programming language.  It's just so useful for getting work done.  Sometimes people will complain that R is a difficult language.  To me, this begs the questions:  difficult for what?  And for whom?  I personally think R is just about the easiest thing in the world for ... [Read more...]

As part of my effort to acquaint myself more with biology, bioinformatics, and statistical genetics, I am trying to find as many resources as I can that provide a solid foundation. For instance, I am wading through Molecular Biology of the Cell at a pa... [Read more...]

Previously, we setup the problem of constructing a minimum expected shortfall portfolio.   We exported the portfolio weights from each quarterly rebalancing into R objects. This post will process those weights and compare the portfolio s... [Read more...]

For those of you who teach, or are interested in seeing an illustrated series of analyses, there is a new compendium of files to help describe how to fit models for the extended case studies in the Second Edition of the Statistical Sleuth: A Course in... [Read more...]

Biostatistician and R user Matt Cooper noticed recently that the price he pays for petrol (gasoline) at the pump in Perth, Australia was about the same as he was paying four years ago. Nonetheless, inflation has marched on over the years, so does that mean petrol is effectively cheaper now ... [Read more...]

Some of my colleagues didn't know that you can use mathematical constants that are part of "cmath". Here is the small snippet that shows how to use PI from cmath library. Be aware that you need to write "#define _USE_MATH_DEFINES" before you include cm... [Read more...]

Bank of America (BoA) has a "Cash Rewards" credit card that pays "1% cash back everywhere, every time"1. But if you read the fine print, it's clear that the reward is almost always less than 1%. Here's the relevant sentence from the terms and conditions2: Fractions are truncated at the 100th decimal ... [Read more...]

To apply a data transformation on an axis in a ggplot, you can use coordinate transformations. For more detail see the ggplot2 documentation. A number of coordinate transformations is available, including log10 and sqrt. However, if you want to perform… See more › [Read more...]

I was introduced to version control at the 2011 Belgrade R+OSGeo in higher education summer school. I’ve been using it in my daily work ever since. Recently the need to branch my project came up and this post describes how after a few hours of reading teh internets satisfied ... [Read more...]

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The 2012 Olympic Games officially ended this Sunday in London. Although I missed most of the games, I was still entertaining myself with some hilarious news, such as Thomas’s re-diving. So much fun. I would remember this for years :) Games ended. … Continue reading → [Read more...]

If you haven’t yet discovered the competitive machine learning site kaggle.com, please do so now. I’ll wait. Great – so, you checked it out, fell in love and have made it back. I recently downloaded the data for the getting started competition. It consists of 42000 labelled images (28×28) of ... [Read more...]

Today I want to highlight a whitepaper about Adaptive Asset Allocation by Butler, Philbrick and Gordillo and the discussion by David Varadi on the robustness of parameters of the Adaptive Asset Allocation algorithm. In this post I will follow the steps of the Adaptive Asset Allocation paper, and in the ... [Read more...]

A new version 0.2.7 of RInside is now available via CRAN. RInside provides a set of convenience classes which facilitate embedding of R inside of C++ applications and programs, using the classes and functions provided by the Rcpp R and C++ integrati... [Read more...]

By Earl F Glynn | Franklin Center A comparison of US Census voting age population data in Missouri to voter registration data shows a number of Missouri counties have bloated voter registration lists. Charts by county for the years 2000 to 2012 show how counties are maintaining their voter lists. Voter fraud potential ... [Read more...]

A question on StackOverflow really sparked my attention. The aim was to clean up a dataset of inappropriately spaced words. For example: [crayon-51c87e2141ce8762175339/] My approach was to create what I call a wordpair object. The word pair object for the… See more › [Read more...]