November 2012

Temporal networks with igraph and R (with 20 lines of code!)

November 10, 2012 | Implicit None » R

In my last post about how a twitter conversation unfolds in time on Twitter, the dynamical nature of information diffusion in twitter was illustrated with a video of the temporal network of interactions (RTs) between accounts. The temporal evolution of … Continue reading →   Related posts: Temporal network of information diffusion in ... [Read more...]

R Tips for Quantitative Trading

November 10, 2012 | rtraderadmin

The article below is an updated version of an article I wrote  for R-Bloggers in August 2010. As a first post I thought it was a good idea to introduce one of the best tool out there for quantitative  trading: R R is a free software environment for statistical computing and ... [Read more...]

Secret Santa

November 10, 2012 | Wingfeet

On reddit somebody asked For n individuals, what's the probability that the last person to pick during a round of Secret Santa name picking, will pick their own name.. "With each person picking in turn, and re-picking if they pick out th... [Read more...]

Back-testing Rules

November 10, 2012 | ivannp

Nowadays there are many trading strategies shared online with reproducible, decent, results. Have you asked yourself, if the strategies are so profitable, why the author bother even sharing them, when the path to riches is clear – just implement the strategy and use it? There are people, of course, who are ... [Read more...]

Using R — .Call(“hello”)

November 9, 2012 | Jonathan Callahan

This entry is part 10 of 12 in the series Using RIn an introductory post on R APIs to C code, Calling C Code ‘Hello World!’, we explored the .C() function with some ‘Hello World!’ baby steps.  In this post …   read more ... [Read more...]

Exploring GAMs with Rosemary Hartman

November 9, 2012 | Noam Ross

Today at Davis R Users’ Group, Rosemary Hartman took us through her work in progress fitting general additive models to organism presence/absence data. Below is her presentation and script. You can get the original script and data here Also, check the comments below for some discussion of other options ... [Read more...]

Video: How John Deere uses R

November 9, 2012 | David Smith

Farming equipment manufacturer John Deere uses R, and in yesterday's webinar their manager of forecast analytics, Derek Hoffman, explained what they use it for: In the presentation, Derek gave a spirited argument of why R is critical for John Deere's operations: from forecasting demand for equipment, to forecasting crop yields (... [Read more...]

Terrain effects on SUHI estimates

November 9, 2012 | Steven Mosher

Introduction Zhang and Imhoff (2010)  pdf here utilized NLCD impervious surface area (ISA), Olson biomes, and MODIS Land Surface temperature (LST) to estimate the magnitude of UHI in large cities across the US.  Peng  employed a   similar approach in studying 419 large cities ( population greater than 1m ) around world. Peng’s work ... [Read more...]

Interactive color picker, using locator()

November 9, 2012 | is.R()

I mostly wrote this just to see how locator() works, and ended up making an HCL color picker, so you can make your own visually offensive rainbow color palettes! Or, you can make your own nice color palettes. It is up to you. Essentially, this script... [Read more...]

R midterms

November 9, 2012 | xi'an

Here are my R midterm exams, version A and version B in English (as students are sitting next to one another in the computer rooms), on simulation methods for my undergrad exploratory statistics course. Nothing particularly exciting or innovative! Dedicated ‘Og‘s readers may spot a few Le Monde puzzles ... [Read more...]

Project Euler — problem 23

November 9, 2012 | Tony

Officially, it’s weekend. I’m solving this 23rd Euler problem just before my supper. A perfect number is a number for which the sum of its proper divisors is exactly equal to the number. For example, the sum of the proper divisors … Continue reading → [Read more...]

Another crosshairs

November 8, 2012 | distantobserver

C. DeSante over at is.R() has PEBOS as well, but turned it into a great explanation of the way predictions like Nate Silver's work.For a while the 538 team had PEBOS as well: "The FiveThirtyEight team is still recuperating, but the election provided a fresh supply of data points ... [Read more...]

R user group

November 8, 2012 | arbuzov1989

The first R user group in Russia has brings together R users in Perm city. First R UseR meetup was 4 october. Arbuzov Vyacheslav presented an overview of the packages for data downloading. peRm R group. Review of packages for … Continue reading → [Read more...]
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