263 search results for "pca"

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

August 3, 2010
By
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...

Read more »

Tutorial: Principal Components Analysis (PCA) in R

May 20, 2010
By

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...

Read more »

Compcache on Ubuntu on Amazon EC2

May 4, 2010
By
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

Read more »

Introducing H2O Lagrange (2.6.0.11) to R

September 1, 2014
By

From my perspective the most important event that happened at useR! 2014 was that I got to meet the 0xdata team and now, long story short, here I am introducing the latest version of H2O, labeled Lagrange (2.6.0.11), to the R and greater data science communities. Before joining 0xdata, I was working at a competitor on a rival project and was repeatedly asked...

Read more »

Extracting Latent Variables from Rating Scales: Factor Analysis vs. Nonnegative Matrix Factorization

August 21, 2014
By
Extracting Latent Variables from Rating Scales: Factor Analysis vs. Nonnegative Matrix Factorization

For many of us, factor analysis provides a gateway to learning how to run and interpret nonnegative matrix factorization (NMF). This post will analyze a set of ratings on a 218 item adjective checklist using both principal axis factor analysis and NMF....

Read more »

A Conversation with Max Kuhn – The useR! 2014 Interview

August 11, 2014
By
youtube___aaaaaaaaaaaaUntitled

The Interview In the video above, Max provides some amazing insights into the why and...

Read more »

Parameterized SQL queries

August 5, 2014
By

Mateusz Żółtak asked me to spread the word about his new R package for parameterized SQL queries. Below you can find the copy of package vignette. If you work with SQL in R you may find it useful. Mateusz Żółtak The package RODBCext is an extension of the RODBC database connectivity package. It provides support

Read more »

Things to try after useR! – Part 1: Deep Learning with H2O

July 25, 2014
By
Things to try after useR! – Part 1: Deep Learning with H2O

Annual R User Conference 2014The useR! 2014 conference was a mind-blowing experience. Hundreds of R enthusiasts and the beautiful UCLA campus, I am really glad that I had the chance to attend! The only problem is that, after a few days of non-stop R talks, I was (and still am) completely overwhelmed...

Read more »

Advanced R Profiling with pbdPAPI

July 22, 2014
By
Advanced R Profiling with pbdPAPI

R has some extremely useful utilities for profiling, such as system.time(), Rprof(), the often overlooked tracemem(), and the rbenchmark package. But if you want more than just simple timings of code execution, you will mostly have to look elsewhere. One of the best sources for profiling data is hardware performance counters, available in most modern hardware. This data can...

Read more »

Introduction to R for Life Scientists: Course Materials

July 7, 2014
By
Introduction to R for Life Scientists: Course Materials

Last week I taught a three-hour introduction to R workshop for life scientists at UVA's Health Sciences Library.I broke the workshop into three sections:In the first half hour or so I presented slides giving an overview of R and why R is so awesome. Du...

Read more »