# 2903 search results for "twitter"

## Generating sets of permutations

October 21, 2011
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In previous posts I discussed how to generate a single permutation from a fully-randomised or restricted permutation design using shuffle(). Here I want to briefly mention the shuffleSet() function and illustrate it’s usage. Every time you call shuffle() it has to interpret the … Continue reading →

## le Monde puzzle [#745]

October 20, 2011
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The puzzle in Le Monde this weekend is not that clear (for a change!), so I may be confused in the following exposition: Three card players are betting with a certain (and different) number of chips each, between 4 and 9. After each game, the looser doubles the number of chips of the winner (while

## postdoctoral positions in Paris

October 20, 2011
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There is a call for postdoctoral positions supported by the Paris Mathematical Sciences Foundation. The deadline is December 13 and the on-line application is available. If you are interested in working with me on Bayesian statistics  (model choice, time series model) or computational methods (SMC, MCMC, ABC, &c.) thru this call, please contact me at

## Minimum Investment and Number of Assets Portfolio Cardinality Constraints

October 19, 2011
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The Minimum Investment and Number of Assets Portfolio Cardinality Constraints are practical constraints that are not easily incorporated in the standard mean-variance optimization framework. To help us impose these real life constraints, I will introduce extra binary variables and will use mixed binary linear and quadratic programming solvers. Let’s continue with our discussion from Introduction

## the Wang-Landau algorithm reaches the flat histogram in finite time

October 19, 2011
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Pierre Jacob and Robin Ryder (from Paris-Dauphine, CREST, and Statisfaction) have just arXived (and submitted to the Annals of Applied Probability) a neat result on the Wang-Landau algorithm. (This algorithm, which modifies the target in a sort of reweighted partioned sampling to achieve faster convergence, has always been perplexing to me.)  They show that some

## How does Matt kemp become Andre Dawson?

October 18, 2011
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While reading this article over at Fangraphs I was inspired to ask myself “what would Matt Kemp have to do between now and then end of his career to be seriously considered for the Hall of Fame?”.  This question comes … Continue reading →

## Generating restricted permutations with permute

October 18, 2011
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In a previous post I introduced the permute package and the function shuffle(). In that post I got as far as replicating R’s base function sample(). Here I’ll briefly outline how shuffle() can be used to generate restricted permutations. shuffle() … Continue reading →

## 130/30 Porfolio Construction

October 18, 2011
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The 130/30 funds were getting lots of attention a few years ago. The 130/30 fund is a long/short portfolio that for each \$100 dollars invested allocates \$130 dollars to longs and \$30 dollars to shorts. From portfolio construction perspective this simple idea is no so simple to implement. Let’s continue with our discussion from Introduction

## Short selling, volatility and bubbles

October 17, 2011
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Yesterday, I wrote a post (in French) about short-selling in financial market since some journalists claimed that it was well-known that short -selling does increase volatility on financial market. Not only in French speaking journals actually, sin...

## R Tools for FEC Campaign Finance Disclosure Data

October 17, 2011
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For my first contribution to the blog, I wanted to make some kind of enlightening visualization of campaign finance disclosure data from the Federal Election Commission’s website. It looks like they’re working on some new, easy-to-use data dumps here, but … Continue reading →