# Monthly Archives: July 2012

## Project Euler — problem 16

July 21, 2012
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The 16th problem is another big-number problem: 215 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26. What is the sum of the digits of the number 21000? This … Continue reading →

## Base versus grid graphics

In a comment in response to my latest post, Robert Young took issue with my characterization of grid as an R graphics package. Perhaps grid is better described as a “graphics support package,” but my primary point – and the main point of this post – is that to generate the display you want, it is sometimes necessary to use commands...

## The magic of the year 1901

July 21, 2012
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The year 1901 is rather magical. Well it is for R provided you run it under Linux. Let me show you why. I have four data points, one from 1900, two from 1901, and one from 1902. dates values I convert them in two different ways; as a Date, and as a POSIXct. For...

## Emulating dynamic scoping in GNU R

July 21, 2012
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By design GNU R uses lexical scoping. Fortunately it allows for at least two ways to simulate dynamic scoping.Let us start with the example code and next analyze it:x <- "global"f1 <- function() cat("f1:", x, "\n")f2 <- function() cat("f2:", e...

## googleVis — where did SYTYCD dancers come from?

July 21, 2012
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After watching 20 wonderful dancers of the 9th season of So You Think You Can Dance, I have presented a geomap of  the states where they are coming from (click here). Now, I am interested to this show’s history.  I’d like to re-draw the … Continue reading →

## Automatic Hyperparameter Tuning Methods

July 20, 2012
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At MSR this week, we had two very good talks on algorithmic methods for tuning the hyperparameters of machine learning models. Selecting appropriate settings for hyperparameters is a constant problem in machine learning, which is somewhat surprising given how much expertise the machine learning community has in optimization theory. I suspect there’s interesting psychological and

## Le Monde puzzle [#783]

July 20, 2012
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$Le Monde puzzle [#783]$

In a political party, there are as many cells as there are members and each member belongs to at least one cell. Each cell has five members and an arbitrary pair of cells only shares one member. How many members are there in this political party? Back to the mathematical puzzles of Le Monde (science

## R Journal, June 2012

July 20, 2012
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The June 2012 issue of the R Journal, the peer-reviewed open-journal about R packages and applications of R, is now available. This issue includes articles about: Efficiently calling C functions from R without the need for wrapper code Using clusters of Macs running Apple Xgrid for parallel distributed processing with R Semi-automated text classification with the 'maxent' package Two...

## Modeling Permanent and Gradual Process Changes with CDFs

July 20, 2012
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Spencer HerathSpecial thanks to Ben OgorekBackgroundI recently faced a process with a structural change resulting in an increase in the process mean.  The jump to the new mean was not immediate; rather, there was a gradual increase in values over time.  I had previously benefited from multi-staged process-behavior charts when encountering immediate process shifts, but now I needed a...

## Look ma! No typing! Autorunning code on R startup

July 20, 2012
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Regular readers may know that I often make R-based GUIs. They’re great for giving non-technical users safe and easy access to statistical models. The safety comes from the restrictions of a GUI: you can limit what the users does more easily than with a command line, helping to reduce the number of opportunities for bad