Posts Tagged ‘ R ’

splitting a field by annealing

October 17, 2017
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splitting a field by annealing

A recent riddle [from The Riddle] that I pondered about during a [long!] drive to Luxembourg last weekend was about splitting a square field into three lots of identical surface for a minimal length of separating wire… While this led me to conclude that the best solution was a T like separation, I ran a […]

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Astrostatistics school

October 17, 2017
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Astrostatistics school

What a wonderful week at the Astrostat [Indian] summer school in Autrans! The setting was superb, on the high Vercors plateau overlooking both Grenoble [north] and Valence [west], with the colours of the Fall at their brightest on the foliage of the forests rising on both sides of the valley and a perfect green on […]

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Halifax, NS, Stan talk and course Thu 19 Oct

October 12, 2017
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Halfiax, here we come. I (Bob, not Andrew) am going to be giving a talk on Stan and then Mitzi and I will be teaching a course on Stan after that. The public is invited, though space is limited for the course. Here are details if you happen to be in the Maritime provinces. TALK: […] The post Halifax, NS, Stan talk and course Thu 19 Oct appeared first on…

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[summer Astrostat school] room with a view [jatp]

October 9, 2017
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[summer Astrostat school] room with a view [jatp]

I just arrived in Autrans, on the Plateau du Vercors overlooking Grenoble and the view is fabulistic! Trees have started to turn red and yellow, the weather is very mild, and my duties are restricted to teaching ABC to a group of enthusiastic astronomers and cosmologists..! Second advanced course on ABC in the mountains this […]

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mea culpa!

October 8, 2017
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mea culpa!

An entry about our Bayesian Essentials book on X validated alerted me to a typo in the derivation of the Gaussian posterior..! When deriving the posterior (which was left as an exercise in the Bayesian Core), I just forgot the term expressing the divergence between the prior mean and the sample mean. Mea culpa!!!Filed under: […]

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Stan Roundup, 6 October 2017

October 6, 2017
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I missed last week and almost forgot to add this week’s. Jonah Gabry returned from teaching a one-week course for a special EU research institute in Spain. Mitzi Morris has been knocking out bug fixes for the parser and some pull requests to refactor the underlying type inference to clear the way for tuples, sparse […] The post Stan Roundup, 6 October 2017 appeared first on Statistical Modeling, Causal Inference,…

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Partial Pooling for Lower Variance Variable Encoding

September 28, 2017
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Partial Pooling for Lower Variance Variable Encoding

Banaue rice terraces. Photo: Jon Rawlinson In a previous article, we showed the use of partial pooling, or hierarchical/multilevel models, for level coding high-cardinality categorical variables in vtreat. In this article, we will discuss a little more about the how and why of partial pooling in R. We will use the lme4 package to fit … Continue reading Partial Pooling for Lower Variance Variable Encoding

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How Good is That Random Number Generator?

September 28, 2017
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How Good is That Random Number Generator?

Recently, I saw a reference to an interesting piece from 2013 by Peter Grogono, a computer scientist now retired from Concordia University. It's to do with checking the "quality" of a (pseudo-) random number generator.Specifically, Peter discusses what...

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How Good is That Random Number Generator?

September 28, 2017
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How Good is That Random Number Generator?

Recently, I saw a reference to an interesting piece from 2013 by Peter Grogono, a computer scientist now retired from Concordia University. It's to do with checking the "quality" of a (pseudo-) random number generator.Specifically, Peter discusses what...

Read more »

Custom Level Coding in vtreat

September 25, 2017
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Custom Level Coding in vtreat

One of the services that the R package vtreat provides is level coding (what we sometimes call impact coding): converting the levels of a categorical variable to a meaningful and concise single numeric variable, rather than coding them as indicator variables (AKA "one-hot encoding"). Level coding can be computationally and statistically preferable to one-hot encoding … Continue reading Custom Level Coding in vtreat

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