352 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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R benchmark for High-Performance Analytics and Computing (I)

April 14, 2016
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R benchmark for High-Performance Analytics and Computing (I)

  Objectives of Experiments R is more and more popular in various fields, including the high-performance analytics and computing (HPAC) fields. Nowadays, the architecture of HPC system can be classified as pure CPU system, CPU + Accelerators (GPGPU/FPGA) heterogeneous system, CPU + Coprocessors system. In software side, high performance scientific libraries, such as basic linear

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Perform co-operations with the coop package

April 6, 2016
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About The coop package does co-operations: covariance, correlation, and cosine, and it does them quickly. The package is available on CRAN and GitHub, and has two vignettes: Introducing coop: Fast Covariance, Correlation, and Cosine Operations Algorithms and Benchmarks for the coop Package Incidentally, the vignettes don't render correctly on CRAN's end for some reason; if any of you rmarkdown...

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Are you doing parallel computations in R? Then use BiocParallel

March 6, 2016
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Are you doing parallel computations in R? Then use BiocParallel

It’s the morning of the first day of oral conferences at #ENAR2016. I feel like I have a spidey sense since I woke up 3 min after an email from Jeff Leek; just a funny coincidence. Anyhow, I promised Valerie Obenchain at #Bioc2014 that I would write a post about one of my favorite Bioconductor packages:...

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Nairobi Data Science Meetup: Paradigm Shift in Research with Samuel Kamande

March 1, 2016
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Samuel Kamande is a Data Scientist at Nielsen and his presentation will focus on “Paradigm Shift in Research”. We caught up with him and he shared a lot about his work at Nielsen, some of the projects he has worked on like “Digital Divide project in Trinidad and Tobago in 2013”,thoughts on the future of Data Science and something...

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