2443 search results for "twitter"

Calling Google Maps API from R

October 5, 2011
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Calling Google Maps API from R

Hi, Related to Julyan’s previous post, I want to share an easy way to access Google Maps API through R. And then we’ll stop about Google, otherwise it’ll look like we’re just looking for jobs. My problem was the following: … Continue reading →

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Interactive charts with googleVis package and R

October 4, 2011
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Interactive charts with googleVis package and R

Examples at the link below illustrate interactive charts created with the googleVis package and R. http://code.google.com/p/google-motion-charts-with-r/wiki/GadgetExamples Some amazing features are: a motion chart shows the changes over time, an AnnotatedTimeLine shows zoom-in/zoom-out view of time series, a TreeMap supports drill-down … Continue reading →

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Introduction to PloTA library in the Systematic Investor Toolbox

October 4, 2011
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Introduction to PloTA library in the Systematic Investor Toolbox

PloTA ( plot + ta ) library in the Systematic Investor Toolbox is a simple plot interface to charting Time Series and Technical Analysis plots. I created it as an alternative to charting functionality in quantmod package. It is designed to mimic default plot interface and works with xts objects. PloTA implements following methods: plota

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permute: a package for generating restricted permutations

October 4, 2011
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permute: a package for generating restricted permutations

Multivariate ordination methods are commonly used in ecology to investigate patterns in species composition in space or time. Constrained ordination methods such as redundancy analysis (RDA) and canonical correspondence analysis (CCA) are effectively just multiple regressions, but we lack the … Continue reading →

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Visualizing Climbing Ropes

October 3, 2011
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Visualizing Climbing Ropes

Today’s market of climbing ropes offers a huge variety of models to choose from. If you don’t have a good idea of what you want, the task of selecting a rope can become a true challenge, or worst, almost a … Continue reading →

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vectorplot in rasterVis

October 2, 2011
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vectorplot in rasterVis

The function slopeAspect from raster provides the vector field (gradient) from a scalar field stored in a RasterLayer object. The magnitude (slope) and direction (aspect) of the vector field is usually displayed with a set of arrows (e.g. quiver in Matlab). rasterVis includes now a method, vectorplot, to calculate and display this vector field

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Customizing your .rprofile

September 29, 2011
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I searched around to see if there was a blog post somewhere describing how to customize one’s .rprofile but was surprised to find just one outdated post. So here is quick intro on the topic. If you are a power R user, you already know about what it does. For those of you that don’t,

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Googling Bayes’ pictures

September 29, 2011
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Googling Bayes’ pictures

I am writing way too many posts in a row on Google tools. I promise I will think about something else soon. I find amusing the possibility to launch a search in Google images by just dragging a picture into … Continue reading →

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Data Science: a literature review

September 28, 2011
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Data Science: a literature review

Just what is Data Science, anyway? Here's one take: Ever since the term "Data Scientist" was coined by DJ Patil and Jeff Hammerbacker in 2009, there's been a vigorous debate on what the team actually means. More than 80% of statisticians consider themselves data scientists, but Data Science is more than just Statistics. (My own take is that Data...

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Bessel integral

September 28, 2011
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Bessel integral

Pierre Pudlo and I worked this morning on a distribution related to philogenic trees and got stuck on the following Bessel integral where In is the modified Bessel function of the first kind. We could not find better than formula 6.611(4) in Gradshteyn and Ryzhik. which is for a=0… Anyone in for a closed form

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