Blog Archives

A multidimensional "which" function

September 16, 2011
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A multidimensional "which" function

The well-known which function accepts a logical vector and returns the indices where its value equals TRUE. Actually, which also accepts matrices or multidimensional arrays. Internally, R uses a single index to run through such two- or higher-dimension...

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Fourier-Motzkin elimination with the editrules package

August 26, 2011
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Fourier-Motzkin elimination with the editrules package

Last week I talked about our editrules package at the useR!2011 conference. In the coming time I plan to write a short series of blogs about the functionality of editrules. Below I describe the eliminate and isFeasible functions. But first: a bit ...

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useR!2011

August 19, 2011
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useR!2011

useR!2011 ended yesterday. First of all, much thanks to the organizers who managed to run a conference with 400+ participants, from 41 countries smoothly. Thumbs up! It was great to meat some people from the R blog-O-sphere in person, like Tal "R-blogg...

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Improving data quality with deducorrect

July 1, 2011
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Improving data quality with deducorrect

Does your raw numerical data suffer from typos? sign errors? variable swaps? rounding errors? You may be able to fix all that with the deducorrect package. Today, we (that is Edwin de Jonge, Sander Scholtus and myself) uploaded the, 1.0-0 release to CR...

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Simple pattern detection in numerical data

May 26, 2011
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Simple pattern detection in numerical data

A while ago I helped out a colleague who was testing some methods to detect economic (in)activity of companies, based on their quarterly tax declarations (our institute has access to such data). One of the thing my colleague wanted was t...

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