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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see if there was a blog post somewhere describing how to customize one’s .rprofile but was surprised to find just one outdated post.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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World Tourism Day, and Google Public Data Explore

September 27, 2011
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World Tourism Day, and Google Public Data Explore

Today is the World Tourism Day! So let’s speak about some tourism related datasets – and others. Among other nice functions, Google offers a Public Data Explore in a beta version which provides a collection of datasets from OECD, IMF, Eurostat, … Continue reading →

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Five new local R user groups

September 27, 2011
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Looks like there's been a lot of activity in the R user community in the Northern hemisphere now that the summer break is over. I've just added several new groups to the Local R User Group Directory: Tokyo, Japan: The Tokyo.R R study group has already had 17 meetings, but has just been added to the directory. Shanghai/East China:...

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