2309 search results for "map"

The performance cost of a for-loop, and some alternatives

August 21, 2011
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I’ve recently been spending a lot of time running various simulations in R. Because I often use snow to perform simulations across several computers/cores, results typically come back in the form of a list object. Summarizing the results from a list … Continue reading →

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Prime testing function in R

August 20, 2011
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Prime testing function in R

I was hoping to begin tinkering a bit with the multicore package in R beyond some extremely trivial examples.  Thanks to a combination of R’s dumb quirkiness (for example, being worthless on loops), my poor planning, and general bad programming, my Saturday afternoon tinkering project is ultimately worthless in fulfilling that purpose. I was really

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useR! Conference 2011 highlights

August 20, 2011
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useR! Conference 2011 highlights

I was at the useR! Conference at The University of Warwick in Coventry, UK, last week. My goal in going was to learn the latest things regarding (simple) dynamic graphics, (simple) web-based apps, parallel computing, and memory management (dealing with big data sets). I got just what I was hoping for and more. There are

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Relation Between Fires and Distanse to the Nearest Highway

August 19, 2011
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Relation Between Fires and Distanse to the Nearest Highway

Instead of introduction Just for fun I decided to investigate relationship between fires intensity in Leningrad region (and St. Petersburg as well) and distance to the nearest road in order to gain the evidence of the major influence of the anthropogen...

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useR! 2011 roundup

August 19, 2011
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useR! 2011 roundup

As I stand here at Heathrow waiting for my flight back to the States, I thought I'd dash off a few quick reflections of the userR! 2011 conference at University Warwick. It was an outstanding event. There's something about a conference of just a few hundred attendees (there were about 450) that creates a sense of camaraderie and common...

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Development of R (useR! 2011)

August 19, 2011
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Development of R (useR! 2011)

Michael Rutter – R for Ubuntu Ubuntu 10.10 uses 2.10.1. Backports are newer versions of software for old releases. R backports are available CRAN (link). Lauchpad is a website for users to develop and maintain software (Canonical). One of Launchpad’s services is the personal package archive (PPA). This allows users to upload .deb source files, allowing

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Simon Urbanek – R Graphics: supercharged

August 18, 2011
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Simon Urbanek – R Graphics: supercharged

New features: rasterImage() (R2.11) bitmap raster drawing; have maps as data backdrops. Polygons with holes: polypath() -(R2.12) At present there is no way to tell when to actually show the plot. For example: plot(x); lines(x). Should we display the plot after plot or after lines Solution dev.hold() and dev.flush() Better performance and useful for animations –

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Kaleidoscope IIIb (useR! 2011)

August 18, 2011
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Kaleidoscope IIIb (useR! 2011)

O. Mersmann - The microbenchmark package Slides and code (link). SURGEON GENERAL’s WARNING: Microbenchmarks can lead to a distorted view of reality and massive loss of productivity For a higher-order benchmarking package check out the rbenchmark package on R (suggestion from the speaker). Why do we need micro-benchmarking? A simple example showed that it is currently very

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Introduction

August 17, 2011
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Introduction

I’m at the useR! Conference in Coventry, UK, this week. It’s been every bit as inspiring, interesting and useful as I’d hoped. Particularly interesting were the Lightning talks: a series of 5 minute presentations with one minute in between, with each presentation having 15 slides of 20 sec each, moved forward automatically.  It worked extremely

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Programming (useR! 2011)

August 17, 2011
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Programming (useR! 2011)

Ray Brownrigg – Tips and Tricks for young R programmers Problem: Calculate the distribution function of a bivariate Kolomogorov Smirnoff statistic. Essentially three loops. Basic exhaustive search is O(N^3). Fortran gives a single order of magnitude speed-up. Restructuring in R using a single loop is an order faster than fortran. Further improvements make the algorithm

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