Posts Tagged ‘ Uncategorized ’

A simple example of parallel computing on a Windows (and also Mac) machine

May 8, 2012
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A simple example of parallel computing on a Windows (and also Mac) machine

by Yanchang Zhao, RDataMining.com With a Mac, parallel computing can be achieved with package multicore. Unfortunately, it does not work under Windows. A simple way for parallel computing under Windows (and also Mac) is using package snowfall, which can work … Continue reading →

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Online resources for handling big data and parallel computing in R

May 6, 2012
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Online resources for handling big data and parallel computing in R

by Yanchang Zhao, RDataMining.com Compared with many other programming languages, such as C/C++ and Java, R is less efficient and consumes much more memory. Fortunately, there are some packages that enables parallel computing in R and also packages for processing … Continue reading →

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Ack! Duplicates in the Data!

May 3, 2012
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Ack!  Duplicates in the Data!

As I mentioned in a previous post, I compiled the data set that I’m currently working on in PostgreSQL.  To get this massive data set, I had to write a query that was massive by dint of the number of … Continue reading →

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EU rules that computer languages cannot be copyrighted

May 2, 2012
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EU rules that computer languages cannot be copyrighted

The European Court of Justice has published its decision in SAS v WPL; the title of the press release says it all “The functionality of a computer program and the programming language cannot be protected by copyright”. To summarise the background, World Programming Ltd developed a system that was capable of emulating the input/output behavior

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2nd round of call for chapter proposals for book Data Mining Applications with R: due by 31 May

May 2, 2012
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2nd round of call for chapter proposals for book Data Mining Applications with R: due by 31 May

2nd CALL FOR CHAPTERS: proposals due by 31 May 2012 Data Mining Applications with R A book to be published by Elsevier http://www.RDataMining.com/books/book2 Introduction —————— R is one of the most widely used data mining tools in scientific and business … Continue reading →

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Mining for relations between nominal variables

May 1, 2012
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Mining for relations between nominal variables

The task today was to find what variables had significant relations with an important grouping variable in the big dataset I’ve been working with lately.  The grouping variable has 3 levels, and represents different behaviours of interest.  At first I … Continue reading →

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Incompetence borne of excessive cleverness

April 29, 2012
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I have just got back from the 24 hour Data Science Global Hackathon; I was an on-site participant at Hub Westminster in London (thanks to Carlos and his team for doing such a great job looking after us all {around 50 turned up from the 100 who registered; the percentage was similar in other cities

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Guess who wins: apply() versus for loops in R

April 28, 2012
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Guess who wins: apply() versus for loops in R

Yesterday I tried to do some data processing on my really big data set in MS Excel. Wow, did it not like handling all those data!! Every time I tried to click on a different ribbon, the screen didn’t even … Continue reading →

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An academic programming language paper about R

April 27, 2012
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An academic programming language paper about R

The R language has passed another milestone, a paper aimed at the academic programming language community (or at least one section of this community) has been written about it, Evaluating the Design of the R Language by Morandat, Hill, Osvald and Vitek. Hardly earth shattering news, but it may have some impact on how R

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R Tips: lots of tips for R programming

April 26, 2012
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R Tips: lots of tips for R programming

by Yanchang Zhao, RDataMining.com There are more than 100 R tips at http://pj.freefaculty.org/R/Rtips.html, which provide quick examples to small challenges in everyday R programming, especially for users switching from other languages to R. There is also a .PDF version for … Continue reading →

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