291 search results for "PCA"

PCA file calculation with "R".

December 5, 2011
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PCA file calculation with "R".

X es la matriz centrada (X is the centered matrix). Xcov es la matriz de covarianzas de X (Xcov is the covariance matrix of X).Con la función "eigen" calculamos los "eigenvectors" y "eigenvalues" de Xcov.(With the function "eigen" we calculate the "ei...

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Big-Data PCA: 50 years of stock data

June 17, 2011
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Big-Data PCA: 50 years of stock data

In this post, Revolution engineer Sherry LaMonica shows us how to use the RevoScaleR big-data package in Revolution R Enterprise to do principal components analysis on 50 years of stock market data -- ed. Principal components analysis, or PCA, seeks to find a set of orthogonal axes such that the first axis, or first principal component, accounts for as...

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Principal Component Analysis (PCA) vs Ordinary Least Squares (OLS): A Visual Explanation

September 16, 2010
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Principal Component Analysis (PCA) vs Ordinary Least Squares (OLS): A Visual Explanation

Over at stats.stackexchange.com recently, a really interesting question was raised about principal component analysis (PCA). The gist was “Thanks to my college class I can do the math, but what does it MEAN?” I felt like this a number of times in my life. Many of my classes were focused on the technical implementations they kinda

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Using R and r.mapcalc (GRASS) to Estimate Mean Topographic Curvature

August 3, 2010
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Using R and r.mapcalc (GRASS) to Estimate Mean Topographic Curvature

Recently I was re-reading a paper on predictive soil mapping (Park et al, 2001), and considered testing one of their proposed terrain attributes in GRASS. The attribute, originally described by Blaszczynski (1997), is the distance-weighted mean differe...

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Tutorial: Principal Components Analysis (PCA) in R

May 20, 2010
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Found this tutorial by Emily Mankin on how to do principal components analysis (PCA) using R. Has a nice example with R code and several good references. The example starts by doing the PCA manually, then uses R's built in prcomp() function to do the s...

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Compcache on Ubuntu on Amazon EC2

May 4, 2010
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Compcache on Ubuntu on Amazon EC2

The following fully-automatic Bash script downloads, compiles, and initializes compcache version 0.6.2 on Ubuntu Karmic Koala (9.10). This script creates two swaps with a maximum of 4GB uncompressed size each. Two swaps are used to take advantage of 2 CPUs (or CPU cores in a multicore CPU). Compcache is a fascinating memory compression system. The

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Interactive maps for the web in R

May 15, 2015
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Interactive maps for the web in R

Static MapsIn the last post I showed how to download economic data from the World Bank's website and create choropleth maps in R (Global Economic Maps).In this post I want to focus more on how to visualize those maps.Sp PackageProbably the simplest way...

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Reinventing the wheel for ordination biplots with ggplot2

May 14, 2015
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Reinventing the wheel for ordination biplots with ggplot2

I’ll be the first to admit that the topic of plotting ordination results using ggplot2 has been visited many times over. As is my typical fashion, I started creating a package for this purpose without completely searching for existing solutions. Specifically, the ggbiplot and factoextra packages already provide almost complete coverage of plotting results from

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Global Economic Maps

May 12, 2015
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Global Economic Maps

IntroductionIn this post I am going to show how to extract data from web pages in table format, transform these data into spatial objects in R and then plot them in maps.ProcedureFor this project we need the following two packages: XML and raster.The first package is used to extract data from HTML pages, in particular from the sections marked...

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7 new R jobs (2015-05-11)

May 11, 2015
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7 new R jobs (2015-05-11)

This is the bimonthly post (for 2015-05-11) for new R Jobs from R-users.com. Employers: visit this link to post a new R job to the R community (it’s free and quick). Job seekers: please follow the links below to learn more and apply for your job of interest (or visit previous R jobs posts). Full-Time Research & Analytics Manager Medallia, Inc. – Posted by pkriss Palo Alto California, United States 10...

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