R and Sudoku solvers: Plus ca change…

February 25, 2010
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Christian Robert blogged about a particularly heavy-handed solution to last Sunday's Sudoku puzzle in Le Monde. That had my symapthy as I like evolutionary computing methods, and his chart is rather pretty. From there, this spread on to the REvolutions...

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R and Sudoku solvers: Plus ca change…

February 25, 2010
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Christian Robert blogged about a particularly heavy-handed solution to last Sunday's Sudoku puzzle in Le Monde. That had my symapthy as I like evolutionary computing methods, and his chart is rather pretty. From there, this spread on to the REvolutions blogs where David Smith riffed on it, and showed the acual puzzle. That didn't stop things as Christian blogged once more about...

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Welcome, Robin!

February 25, 2010
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Welcome, Robin!

Robin Ryder started his new blog with his different solutions to Le Monde puzzle of last Saturday (about the algebraic sum of products…), solutions that are much more elegant than my pedestrian rendering. I particularly like the one based on the Jacobian of a matrix! (Robin is doing a postdoc in Dauphine and CREST—under my

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Responding to the Flowingdata GDP Graph Challenge

February 25, 2010
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Responding to the Flowingdata GDP Graph Challenge

Nathan Yau of Flowingdata put up a challenge earlier today to improve upon a graph showing government spending as a percentage of GDP, published in the Economist. The underlying data wasn’t available. So I put on my graph-to-numbers glasses on and pulled out some data. Here it is in case you want to have a

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Nutritional supplements efficacy score – Graphing plots of current studies results (using R)

February 25, 2010
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Nutritional supplements efficacy score – Graphing plots of current studies results (using R)

In this post I showcase a nice bar-plot and a balloon-plot listing recommended Nutritional supplements , according to how much evidence exists for thier benefits, scroll down to see it(and click here for the data behind it) * * * * The gorgeous blog “Information Is Beautiful” recently publish an eye candy post showing a “balloon race” image...

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Solving Sudoku with Simulated Annealing

February 25, 2010
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Solving Sudoku with Simulated Annealing

How long would it take you to solve this devlishly hard Sudoku puzzle (from Le Monde)? You could do it the old-fashioned way -- with a pencil -- but Xi'an decided to solve it by programming a simulated annealing solver in R. The algorithm works by first guessing a solution at random -- filling in the empty cells above...

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inkblot: an alternative to stacked bar graphs

February 25, 2010
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inkblot: an alternative to stacked bar graphs

Sometimes it is not easy to get useful information from a stacked bar chart, see for instance this blogpost at Support Analytics.So-called inkblot charts, as discussed at Kaiser Fung's Junk Charts, allow the reader to focus on the evolution of a time series.Now how to make this kind of charts with R? I asked on StackOverflow....

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Interaction plot from cell means

February 24, 2010
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Interaction plot from cell means

I needed to produce a few a interaction plots for my book in R and, while the interaction.plot() function is useful it has a couple of drawbacks. First, the default output isn't very pretty. Second, it works from the raw data, whereas I often need plot...

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FFT (Fast Fourier Transform) of time series — promises and pitfalls towards trading

February 24, 2010
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FFT (Fast Fourier Transform) of time series  — promises and pitfalls towards trading

Fig 1. FFT transformed time series (EBAY) reconstructed with first three and twenty harmonics, respectively.I see quite a few traders interested in advanced signal processing techniques. It is often instructive to see why they may or may not be useful....

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ggplot2: Plotting Dates, Hours and Minutes

February 24, 2010
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ggplot2: Plotting Dates, Hours and Minutes

Plotting timeseries with dates on x-axis and times on y-axis can be a bit tricky in ggplot2. However, with a little trick this problem can be easily overcome. Let’s assume that I wanted to plot when the sun rises in London in 2010. sunriset function in maptools package calculates the sunrise times using algorithms provided

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PoRtable…

February 24, 2010
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PoRtable…

Jobless as I might be, I do have some clients for data analysis. I try not to visit them in their office coz then things get really slow and time-consuming. When I can’t escape this, the worst thing is tuning data and software with client. So, I have a USB with portable versions of my

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Object types in R: The fundamentals

February 24, 2010
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If you're a self-taught R programmer, you've probably grappled with the different kinds of objects you can use in the language. When should you use a list instead of a vector? What's the difference between a factor and character vector? These questions are easier to answer when you have some of the basics of R's object types down pat,...

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SoilWeb iPhone App: Beta-Testers?

February 23, 2010
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SoilWeb iPhone App: Beta-Testers?

iPhone App Screenshot rev 0.2 - icon iphone App Screenshot rev 0.2 - in Fresno   More Updates: The application is now...

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Reminder: useR! 2010 abstracts due Monday

February 23, 2010
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Don't forget, if you're planning to attend the R user conference useR! 2010 and are going to present a talk (and if not, why not?), abstracts are due for submission this coming Monday, March 1. That's also the deadline for early-bird registrations, so if you haven't registered yet, now is the time. useR! 2010: The R User Conference

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Numerical Integration/Differentiation in R: FTIR Spectra

February 23, 2010
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Numerical Integration/Differentiation in R: FTIR Spectra

  Stumbled upon an excellent example of how to perform numerical integration in R. Below is an example of piece-wise linear and spline fits to FTIR data, and the resulting computed area under the curve. With a high density of points, it seems like the linear approximation is most efficient and sufficiently accurate. With very large...

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Slides from “R Productivity Environment” webinar

February 23, 2010
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Thanks to everyone who attended for the great turnout at this morning's live webinar, 7 Ways to Increase your R Productivity. I really appreciate all the feedback and questions, seems like a lot of people are interested in a code editing and debugging environment for R. If you missed the webinar and want to learn about REvolution R Enterprise...

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Happy Birthday GGD! The 10 Most Popular Posts Since GGD’s Launch

February 23, 2010
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The first post on Getting Genetics Done was one year ago today. To celebrate, here are the top 10 most viewed posts since GGD launched last year. Incidentally, nine of the ten are tutorials on how to do something in R. Thanks to all the readers and all...

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Getting Started with Sweave: R, LaTeX, Eclipse, StatET, & TeXlipse

February 23, 2010
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Getting Started with Sweave: R, LaTeX, Eclipse, StatET, & TeXlipse

Being able to press a single button that runs all your statistical analyses and integrates the output into your final report is a beautiful thing. If you have not already heard, this is what Sweave can do for you. However, getting your computer to run ...

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Getting Started with Sweave: R, LaTeX, Eclipse, StatET, & TeXlipse

February 23, 2010
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Getting Started with Sweave: R, LaTeX, Eclipse, StatET, & TeXlipse

Being able to press a single button that runs all your statistical analyses and integrates the output into your final report is a beautiful thing. If you have not already heard, this is what Sweave can do for you. However, getting your computer to run ...

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Mexico’s Economy

February 22, 2010
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Mexico’s Economy

Yesterday the INEGI released the GDP figures for 2009, and since it was an annus horribilis for Mexico, I thought I'd put up a couple of charts. Looking through the Banco de Información Económica I found two series of historical seasonally adjusted GDP data available:GDP in 1993 pesos going from 1980 to 2007 GDP in 2003 pesos going...

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Mexico’s Economy

February 22, 2010
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Mexico’s Economy

Yesterday the INEGI released the GDP figures for 2009, and since it was an annus horribilis for Mexico, I thought I'd put up a couple of charts. Looking through the Banco de Información Económica I found two series of historical seasonally adjusted GDP data available: GDP in 1993 pesos going from 1980 to 2007 GDP in 2003 pesos going...

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Time Series Calendar Heat Maps Using R

February 22, 2010
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Time Series Calendar Heat Maps Using R

I came across an interesting blog that showcased Charting time series as calendar heat maps in R . It is based upon a great algorithm created by Paul Bleicher,CMO of Humedica. I'll let you link to the other blog to see more details on the background ...

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A quicky..

February 22, 2010
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If you’re (and you should) interested in principal components then take a good look at this. The linked post will take you by hand to do everything from scratch. If you’re not in the mood then the dollowing R functions will help you. An example. # Generates sample matrix of five discrete clusters that have

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Sudoku via simulated annealing

February 22, 2010
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Sudoku via simulated annealing

The Sudoku puzzle in this Sunday edition of Le Monde was horrendously difficult, so after spending one hour with only 4 entries filled, I decided to feed it to the simulated annealing R program I wrote while visiting SAMSI last year. The R program reached the exact (and only) solution in about 6000 iterations, as

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Siegel-Tukey: a Non-parametric test for equality in variability (R code)

February 22, 2010
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Daniel Malter just shared on the R mailing list (link to the thread) his code for performing the Siegel-Tukey (Nonparametric) test for equality in variability. Excited about the find, I contacted Daniel asking if I could republish his code here, and he kindly replied “yes”. From here on I copy his note at full. p.s: (The R function can be downloaded from...

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Speeding up R code: A case study

February 22, 2010
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On his Psychology and Statistics blog, Jeromy Anglim tells how he was analyzing some data from a skill acquisition experiment. Needing to run a custom R function across 1.3 million data points, Jeromy estimated it would take several hours for the computation to complete. So, Jeromy set out to optimise the code. First, he used the Rprof function, which...

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ggplot2 (qplot) text size

February 22, 2010
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I'm trying to learn qplot in ggplot2, and I'm having a difficult time adjusting text sizes. Well, difficult doesn't descibe it - I can't do it at all. The manual tells me I can use cex just like in plot, but it's not working...

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Time-Space Cloud with R

February 22, 2010
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Time-Space Cloud with R

Here comes another option to analyze a TimeSpace-Track with R. A lattice cloud plots every recorded trackpoint into a 3d-time-space-cube. As the data (planar point pattern) is marked with the daytime, cluster of everyday routines become visible. Here the direct comparison between a function of density and the time-space-cloud. Code example: cloud(time_hours ~ PPP_selection$x *

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Post hoc analysis for Friedman’s Test (R code)

February 22, 2010
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Post hoc analysis for Friedman’s Test  (R code)

My goal in this post is to give an overview of Friedman’s Test and then offer R code to perform post hoc analysis on Friedman’s Test results. (The R function can be downloaded from here) Preface: What is Friedman’s Test Friedman test is a non-parametric randomized block analysis of variance. Which is to say it is a non-parametric version of...

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