1011 search results for "latex"

Mathematical functions on non-numbers?!

July 10, 2014
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Mathematical functions on non-numbers?!

A question came up about regarding Q1.4.9 in Cherney, Denton, Waldron. Here is a snippet of the original question: Consider …Continue reading →

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Buster – a new R package for bagging hierarchical clustering

July 9, 2014
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Buster – a new R package for bagging hierarchical clustering

I recently found myself a bit stuck. I needed to cluster some data. The distances between the data points were not representable in Euclidean space so I had to use hierarchical clustering. But then I wanted stable clusters that would retain their shape as I updated the data set with new observations. This I could … Continue reading...

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recycling accept-reject rejections (#2)

July 1, 2014
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recycling accept-reject rejections (#2)

Following yesterday’s post on Rao’s, Liu’s, and Dunson’s paper on a new approach to intractable normalising constants, and taking advantage of being in Warwick, I tested the method on a toy model, namely the posterior associated with n Student’s t observations with unknown location parameter μ and a flat prior, which is “naturally” bounded by

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Tailoring univariate probability distributions

June 26, 2014
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Tailoring univariate probability distributions

This post shows how to build a custom univariate distribution in R from scratch, so that you end up with the essential functions: a probability density function, cumulative distribution function, quantile function and random number generator. In the beginning all you need is an equation of the probability density function, … Continue reading →

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A Simple Shiny App for Monitoring Trading Strategies

June 25, 2014
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A Simple Shiny App for Monitoring Trading Strategies

In a previous post I showed how to use  R, Knitr and LaTeX to build a template strategy report. This post goes a step further by making  the analysis  interactive. Besides the interactivity, the Shiny App also solves two problems : I can now access all my trading strategies from a single point regardless of the instrument traded.

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Conditional Distributions from some Elliptical Vectors

June 18, 2014
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Conditional Distributions from some Elliptical Vectors

This winter, in my ACT8595 course, I asked my students (that was some homework) to prove that it was possible to derive the conditional distribution when we have a Student-t random vector (and to get the analytical expression of the later). But before, let us recall a standard result about the Gaussian vector. If  is a Gaussian random vector, i.e. then  has a...

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R Markdown v2

June 18, 2014
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R Markdown v2

People rarely agree on a best authoring tool or language. Some people cannot live without \LaTeX{} because of the beauty and quality of its PDF output. Some \feel{} \uncomfortable{} \with{} \backslashes{}, and would rather live in another World Word. We have also witnessed the popularity of Markdown, an incredibly simple language (seriously? a LANGUAGE?) that has made reproducible research much easier.

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Tukey and Mosteller’s Bulging Rule (and Ladder of Powers)

June 16, 2014
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Tukey and Mosteller’s Bulging Rule (and Ladder of Powers)

When discussing transformations in regression models, I usually briefly introduce the Box-Cox transform (see e.g. an old post on that topic) and I also mention local regressions and nonparametric estimators (see e.g. another post). But while I was working on my ACT6420 course (on predictive modeling, which is a VEE for the SOA), I read something about a “Ladder of...

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checking for finite variance of importance samplers

June 10, 2014
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checking for finite variance of importance samplers

Over a welcomed curry yesterday night in Edinburgh I read this 2008 paper by Koopman, Shephard and Creal, testing the assumptions behind importance sampling, which purpose is to check on-line for (in)finite variance in an importance sampler, based on the empirical distribution of the importance weights. To this goal, the authors use the upper tail 

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A simple workflow for using R with Microsoft Office products

June 5, 2014
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A simple workflow for using R with Microsoft Office products

The challenge of integrating Microsoft products with R software has been an outstanding issue for several years. Reasons for these issues are complicated and related to fundamental differences in developing proprietary vs open-source products. To date, I don’t believe there has been a satisfactory solution but I present this blog as my attempt to work

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