343 search results for "evaluation"

dplyr 0.3

October 13, 2014
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dplyr 0.3

I’m very pleased to announce that dplyr 0.3 is now available from CRAN. Get the latest version by running: install.packages("dplyr") There are four major new features: Four new high-level verbs: distinct(), slice(), rename(), and transmute(). Three new helper functions between, count(), and data_frame(). More flexible join specifications. Support for row-based set operations. There are two

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R as a general-purpose language for creating DSLs

October 6, 2014
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As a computer scientist, RStudio's Joe Cheng has some great insights into the R language and how it compares with other programming language. In the interview with DataScience.LA below, he notes that while R is often thought about as a domain-specific language (or DSL), the combination of a functional language with deferred evaluation of functional arguments actually makes it...

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Error propagation based on interval arithmetics

September 27, 2014
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Error propagation based on interval arithmetics

I added an interval function to my ‘propagate’ package (now on CRAN) that conducts error propagation based on interval arithmetics. It calculates the uncertainty of a model by using interval arithmetics based on (what I call) a “combinatorial sequence grid evaluation” approach, thereby avoiding the classical dependency problem that often inflates the result interval. This

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Nuts and Bolts of Quantstrat, Part III

September 20, 2014
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Nuts and Bolts of Quantstrat, Part III

This post will focus on signals in quantstrat. In comparison to indicators, signals in quantstrat are far more cut-and-dry, as … Continue reading →

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Creating a map showing land covered by rising sea levels

September 15, 2014
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I joined the Geekli.st climate Hackathon this weekend at the Hub Westminster (my favorite venue for Hackathons). While the organizers had lots of enthusiasm they had very little in the way of data for us to work on. No problem, ever since the Flood-relief hackathon I have wanted to use the SRTM ‘whole Earth’ elevation

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Using colorized PNG pictograms in R base plots

September 12, 2014
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Using colorized PNG pictograms in R base plots

Today I stumbled across a figure in an explanation on multiple factor analysis which contained pictograms.   Figure 1 from Abdi & Valentin (2007), p. 8. I wanted to reproduce a similar figure in R using pictograms and additionally color them e.g. by group membership . I have almost no knowledge about image processing, so

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Build a SPAM filter with R

September 8, 2014
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Build a SPAM filter with R

You can find the complete code on github: https://github.com/JulianHill/R-Tutorials/blob/master/spam_class_r.r   Introduction: The topic Machine Learning gets more and more important. The number of data sources grows everyday and it makes it hard to get... The post Build a SPAM filter with R appeared first on ThinkToStart.

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Points Per Touch (PPT): Running Backs

September 1, 2014
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Points Per Touch (PPT): Running Backs

Overview American writer Lewis Grizzard once said that “The game of life is a lot like football. You have to tackle your problems, block your fears, and score your points The post Points Per Touch (PPT): Running Backs appeared first on Fantasy Football Analytics.

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Entering the field as a data scientist with certification

August 22, 2014
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By Neera Talbert, VP Services and Ben Wiley, R Programmer at Revolution Analytics By now, everyone should be familiar with the data scientist boom. Simply logging onto LinkedIn reveals a seemingly infinite number of people with words and phrases like “Data Scientist”, “Big Data Specialist”, and “Analytics” in their title. A few weeks ago, an article floated around the...

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Optimizing with R expressions

August 21, 2014
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Optimizing with R expressions

I recently discovered a powerful use for R expression()’sSay you are trying to fit some experimental data to the following nonlinear equation: Ky0eu(x−tl)K+y0(eu∗(x−tl)−1)+b1+(b0−b1)e−kx+b2x with the independent variable x using nlminb() as the minimization optimizer.This sort of work is significantly improved (i.e. faster with better convergence) if an analytical gradient vector and a Hessian matrix for the objective function are provided....

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