190 search results for "iris"

“What You’re Doing Is Rather Desperate”

March 22, 2015
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“What You’re Doing Is Rather Desperate”

Self-protrait by Gustave Courbet.Source: WikiMedia Commons.One blog that I have been (occasionally but repeatedly) reading for a long time is the What You're Doing Is Rather Desperate blog by Neil Saunders. HT to WoW!ter for po...

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Aggregation

February 26, 2015
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Aggregation splits data into subsets, computes summary statistics on each subset, and reports the results in a conveniently summarized form. The aggregate function is one of the most capable functions in the scidb package. The package overloads R’s standard aggregate function for SciDB arrays, using reasonably standard R syntax to cover most SciDB aggregation operators The post

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More on Quadratic Progarmming in R

February 10, 2015
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More on Quadratic Progarmming in R

This post is another tour of quadratic programming algorithms and applications in R. First, we look at the quadratic program that lies at the heart of support vector machine (SVM) classification. Then we'll look at a very different quadratic programming demo problem that models the energy of a circus tent. The key...

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A Step to the Right in R Assignments

February 4, 2015
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I received an out-of-band question on the use of %<>% in my CDC FluView post, and took the opportunity to address it in a broader, public fashion. Anyone using R knows that the two most common methods of assignment are the venerable (and sensible) left arrow <- and it’s lesser cousin =. <- has an

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Shiny for Interactive Application Development using R

February 2, 2015
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This slidify-based deck introduces the shiny package from R-Studio and walks one through the development of an interactive application that presents users with options to subset the iris dataset, generate a summary of the resulting dataset, a...

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Getting the most of mix models with random slopes

January 21, 2015
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Getting the most of mix models with random slopes

I use mix models as a way to find general patterns integrating different levels of information (i.e. the random effects). Sometimes you only want to focus on the general effects, but others the variation among levels is also of interest. … Continue reading →

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Canonical Correlation Analysis on Imaging

January 5, 2015
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Canonical Correlation Analysis on Imaging

In imaging, we deal with multivariate data, like in array form with several spectral bands. And trying to come up with interpretation across correlations of its dimensions is very challenging, if not impossible. For example let's recall the number of s...

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Principal Component Analysis on Imaging

December 25, 2014
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Principal Component Analysis on Imaging

Ever wonder what's the mathematics behind face recognition on most gadgets like digital camera and smartphones? Well for most part it has something to do with statistics. One statistical tool that is capable of doing such feature is the Principal Component Analysis (PCA). In this post, however, we will not do (sorry to disappoint you) face recognition as...

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Hassle-free data from HTML tables with the htmltable package

December 15, 2014
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HTML tables are a standard way to display tabular information online. Getting HTML table data into R is fairly straightforward with the readHTMLTable() function of the XML package. But tables on the web are primarily designed for displaying and consuming data, not for analytical purposes. Peculiar design choices for HTML tables are therefore frequently made which tend to produce...

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The ensurer package (validation inside pipes)

November 19, 2014
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The ensurer package (validation inside pipes)

Guest post by Stefan Holst Milton Bache on the ensurer package. If you use R in a production environment, you have most likely experienced that some circumstances change in ways that will make your R scripts run into trouble. Many things can go wrong; package updates, external data sources, daylight savings time, etc. There is a general

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