Last time we looked at the Matrix package and dug a little into the chol(), Cholesky Decomposition, function. I noted that often in finance we do not have a positive definite (PD) matrix. The chol() function in both the Base and Matrix...

Last time we looked at the Matrix package and dug a little into the chol(), Cholesky Decomposition, function. I noted that often in finance we do not have a positive definite (PD) matrix. The chol() function in both the Base and Matrix...

The need to analyze time-series or other forms of streaming data arises frequently in many different application areas. Examples include economic time-series like stock prices, exchange rates, or unemployment figures, biomedical data sequences like electrocardiograms or electroencephalograms, or industrial process operating data sequences like temperatures, pressures or concentrations. As a specific example, the figure below shows four data sequences:...

Here are the presentation slides I used for my talk on “Using R for Data Mining Competitions” at Ryerson University as part of the Greater Toronto Area (GTA) R User’s Meetup Group. Presentation (Prezi) Presentation (PDF) Meetup Event page Special thanks to Anthony Goldbloom from Kaggle and various competition winners for sharing their code and

I follow some 80 odd people/ news sources on my twitter account. For a while I wondered which of these sources are most active on twitter. I picked a simple metric '# of status messages posted to twitter' as the measure of activity. Using R I quickly wrote a program to generate my top 10 most active...

This is another pretty simple function, written to help me solve the simplest representation of a trivial but tedious task. Most biologist are probably familiar with this task. How many nucleotide differences exist between two given sequences? I only faced the easiest part of the problem, i.e. I do not perform alignment, I just assume that

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