Monthly Archives: April 2010

R / Finance 2010 presentations

April 20, 2010
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Last Friday and Saturday the second R / Finance conference took place in Chicago on the UIC campus. As a co-organizer, it was a great pleasure to see so many users of R in Finance---from both industry and academia---come to Chicago to discuss and shar...

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R / Finance 2010 presentations

April 20, 2010
By

Last Friday and Saturday the second R / Finance conference took place in Chicago on the UIC campus. As a co-organizer, it was a great pleasure to see so many users of R in Finance---from both industry and academia---come to Chicago to discuss and sh...

Read more »

Book Review – ggplot 2: Elegant Graphics for Data Analysis by Hadley Wickham (Springer 2009)

April 20, 2010
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Book Review – ggplot 2: Elegant Graphics for Data Analysis by Hadley Wickham (Springer 2009)

Order this book from Amazon This book is written by the author of the ggplot2 package for R, which is a package with a design inspired by the grammar of graphics and can remove some of the effort required to put together impressive graphs. The book is just under 200 pages and covers a

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Data I/O performance tips

April 20, 2010
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The R tag on StackOverflow recently topped 1000 questions, and continues to be a great community resource for practical tips on using the R language for data analysis and visualization. To take one example, "Efficiency of operations on R data structures" has been answered with some great tips on efficiently getting data in and out of the R system....

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R and the Next Big Thing

April 19, 2010
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I've been travelling for the past few days (for the R/Finance 2010 conference in Chicago), so I'd missed much of the reaction to AnnMaria De Mars' article last week where she claimed that "R is an epic fail". Understandably, that inflammatory statement provoked many reactions from the R community on Twitter and in the blogosphere. (I suspect the fact...

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A stateful C function for R: parsing Fasta sequences

April 19, 2010
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In the following post, I'll create a C extension for R. This extension will iterate over all the FASTA sequences in a file and will return a pair(name,sequence) for each sequence, that is to say that I won't store all the sequences in memory.The C code...

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A stateful C function for R: parsing Fasta sequences

April 19, 2010
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In the following post, I'll create a C extension for R. This extension will iterate over all the FASTA sequences in a file and will return a pair(name,sequence) for each sequence, that is to say that I won't store all the sequences in memory.The C code...

Read more »

Converting Alpha-Shapes into SP Objects

April 19, 2010
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Converting Alpha-Shapes into SP Objects

Just read about a new R package called alphahull (paper) that sounds like it might be a good candidate for addressing this request regarding concave hulls. Below are some notes on computing alpha-shapes and alpha-hulls from spatial data and converting the results returned by ashape() and ahull() into SP-class objects. Note that the functions...

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R and Tolerance Intervals

April 19, 2010
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Confidence intervals and prediction intervals are used by statisticians on a regular basis. Another useful interval is the tolerance interval that describes the range of values for a distribution with confidence limits calculated to a particular percentile of the distribution. The R package tolerance can be used to create a variety of tolerance intervals of

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Estimating Missing Data with aregImpute() {R}

April 19, 2010
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  Missing Data Soil scientists routinely sample, characterize, and summarize patterns in soil properties in space, with depth, and through time. Invariably, some samples will be lost or sufficient funds required for complete characterization can run out. In these cases the scientist is left with a data table that contains holes (so to speak) in the rows/columns that are...

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