You should not use split in production code

June 7, 2012
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Recently I have stumbled on a problem with split function applied on list of factors. The issue is that it might produce wrong splits when splitting factors contain dots.Here is the example of the problem. Invoking the following code:df <-...

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R functions to filter rjags results

June 7, 2012
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R functions to filter rjags results

A while back I was running a bunch of JAGS models through R, using the rjags (written by Martyn Plummer) and R2jags (by Yu-Sung Su) packages. These packages provide a great interface to the JAGS software, which allows analysis of … Continue reading →

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PLoS topic page on ABC

June 6, 2012
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PLoS topic page on ABC

A few more comments on the specific entry on ABC written by Mikael Sunnåker et al…. The entry starts with the representation of the posterior probability of an hypothesis, rather than with the posterior density of a model parameter, which seems to lead the novice reader astray. After all, (a) ABC was not introduced for

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Load Packages Automatically in RStudio

June 6, 2012
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Load Packages Automatically in RStudio

I recently finished a long stretch of work on a particular project that required me to draw upon four R packages.  Each time I got back to my work on the project, I’d have to load the packages manually, as … Continue reading →

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Poverty Incidence in the Philippines

June 6, 2012
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Poverty Incidence in the Philippines

Every three (3) years, the National Statistical Coordination Board (NSCB) publish data on provincial poverty incidence in the Philippines. Using R, I put the tabulated poverty incidence data into maps to check pattern and changes on the country's pr...

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Improving Monitor statistics with the "UECLs"

June 6, 2012
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Improving Monitor statistics with the "UECLs"

New Monitor Video:Improving Monitor statistics with the "UECLs"

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Simulating the Birthday Problem with data derived probabilities

June 6, 2012
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Simulating the Birthday Problem with data derived probabilities

You've probably heard of the Birthday Paradox: it only takes a small gathering of people before it's quite likely that two of them share the same birthday. You can solve the problem analytically or with simulation, but usually in either case simplifying assumptions are made (no-one born on February 29, for example). Joe Rickert uses Revolution R Enterprise 6...

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Body Weight in the United States – Part 1, "The Problem"

June 6, 2012
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Body Weight in the United States – Part 1, "The Problem"

The Problem In the United States, people are getting fatter and they are doing so at an alarming rate. So What? Being fat isn't just a social stigma - it's unhealthy in nearly every facet of life. Staying in this condition brings high blood pressure, diabetes, asthma and arthritis to name...

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Claims reserving and IBNR with R

June 6, 2012
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Claims reserving and IBNR with R

Following previous posts on life contingencies and longevity and mortality models, I upload additional material for the short course at the 6th R/Rmetrics Meielisalp Workshop & Summer School on Computational Finance and Financial Engineeri...

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Let’s Party!

June 6, 2012
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Let’s Party!

Exploring whether regression coefficients differ between groups is an important part of applied econometric research, and particularly for research with a policy based objective. For example, a government in a developing country may decide to introduce free school lunches in an effort to improve childhood health. However, if this treatment is known to only improve

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Project Euler — problem 7

June 6, 2012
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Prime is the core of number theory. Here is an introduction of prime number on Wikipedia. I could only understand roughly half of it. Now, let’s look at the seventh problem of Project Euler, which is another about prime number.  By listing the first six prime numbers: 2, 3, … Continue reading →

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2 min HOWTO in R

June 6, 2012
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Lots of short videos on how to do several things in R.

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Facts About R Packages (2)

June 6, 2012
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R Packages All Well maintained? There are so many R packages, can they all be trusted? or are they well maintained? To answer this question, we just need to take a look of their archive histories. If a package has many versions, we can take that as the authors spent a lot of time to make their packages perfect, these...

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R-NOLD 2012-06-06 03:18:00

June 6, 2012
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R-NOLD 2012-06-06 03:18:00

While traveling across the Visayas, I encountered barangay (villages) with the name same as my last name. Using R and map data from gadm.org I search and mapped other villages in the country named “Salvacion”.

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Facts About R Packages (1)

June 6, 2012
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R Packages growth Curve Why R is so popular? There are a lot of reasons, such as: easy to learn and convenient to use, active community, open source, etc. Another important reason is the numerous contributed packages. Up to yesterday, there are 3854 R packages on CRAN. The following figure shows the growth curve of R package:

Managing the deluge of DNA data

June 5, 2012
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Managing the deluge of DNA data

The explosion in DNA sequencing capacity has shifted the experimental bottleneck from sequencing to analyzing and interpreting sequences. The bioconductor package cummeRbund uses ggplot as part of its tool set for organizing, exploring and visualizing ...

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Constants and ARIMA models in R

June 5, 2012
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Constants and ARIMA models in R

This post is from my new book Forecasting: principles and practice, available freely online at OTexts.com/fpp/. A non-seasonal ARIMA model can be written as (1)   or equivalently as (2)   where is the backshift operator, and is the mean of . R uses the parametrization of equation (2). Thus, the inclusion of a constant in a non-stationary ARIMA...

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Quasi-Random Number Generation in R

Random number generation is a core topic in numerical computer science. There are many efficient algorithms for generating random (strictly speaking, pseudo-random) variates from different probability distributions. The figure below shows a sampling of 1000 two-dimensional random variates from the … Continue reading →

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F-test to find UECLs

June 5, 2012
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F-test to find UECLs

I have fixed the link to the video "Removing Y outliers from the validation set" and it´s time to see what could be the next step to the function. As we know the RMSEP is the sum of the explained (BIAS) and unexplained error (SEP). We get also the SEP...

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Example 9.34: Bland-Altman type plot

June 5, 2012
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Example 9.34: Bland-Altman type plot

The Bland-Altman plot is a visual aid for assessing differences between two ways of measuring something. For example, one might compare two scales this way, or two devices for measuring particulate matter. The plot simply displays the difference between the measures against their average. Rather than a statistical test, it is intended...

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NBA Playoff Predictions Update 3 (4-2)

June 5, 2012
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NBA Playoff Predictions Update 3 (4-2)

This is my third update to my original post on predicting the NBA playoffs with an algorithm. Here are updates 1 and 2. The algorithm correctly predicted a Boston win, but missed on the Spurs/Thunder game, so it is currently 4-2. Haven't had any time...

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Digitize linear and (semi-)log scale graphs with multiple point sets

June 5, 2012
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Digitize linear and (semi-)log scale graphs with multiple point sets

Working on a paper, I ran into the problem of needing data from a graph that was not mine, and for which no underlying table was published. With today's software packages, it is however not very difficult to digitize a figure yourself. I remembered rea...

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Announcing Revolution R Enterprise 6.0

June 5, 2012
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Revolution Analytics is proud to announce the latest update to our enhanced, production-grade distribution of R, Revolution R Enterprise. This update expands the range of supported computation platforms, adds new Big Data predictive models, and updates to the latest stable release of open source R (2.14.2), which improves performance of the R interpreter by about 30%. This release expands...

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NBA Playoff Predictions Update 3 (4-2)

June 5, 2012
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NBA Playoff Predictions Update 3 (4-2)

This is my third update to my original post on predicting the NBA playoffs with an algorithm. Here are updates 1 and 2. The algorithm correctly predicted a Boston win, but missed on the Spurs/Thunder game, so it is currently 4-2. Haven't had any time to update yet, so I will only be able to give you predictions for...

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Book Review: Parallel R

June 5, 2012
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Book Review: Parallel R

You have a problem: R is single-threaded, but your code would be faster if it could simultaneously run on more than one core.  You have access to a cluster and/or your computer has multiple cores.  Parallel R, by Q. Ethan McCallum and Stephen...

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intersect for multiple vectors in R

June 5, 2012
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Say you havea <- c(1,3,5,7,9)b <- c(3,6,8,9,10)c <- c(2,3,4,5,7,9)A straightforward way to do the job is:intersect(intersect(a,b),c)More cleverly, and more conveniently if you have a lot of arguments:Reduce(intersect, list(a,b,c))The Reduce fu...

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NBA Playoff Predictions Update 3 (4-2)

June 5, 2012
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NBA Playoff Predictions Update 3 (4-2)

This is my third update to my original post on predicting the NBA playoffs with an algorithm. Here are updates 1 and 2. The algorithm correctly predicted a Boston win, but missed on the Spurs/Thunder game, so it is currently 4-2. Haven't had any time ...

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UK house prices visualised with googleVis-0.2.16

June 5, 2012
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UK house prices visualised with googleVis-0.2.16

A new version of googleVis has been released on CRAN and the project site. Version 0.2.16 adds the functionality to plot quarterly and monthly data as a motion chart. To illustrate the new feature I looked for a quarterly data set and stumbled across t...

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Volatility Quantiles

June 4, 2012
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Volatility Quantiles

Today I want to examine the performance of stocks in the S&P 500 grouped into Quantiles based on one year historical Volatility. The idea is very simple: each week we will form Volatility Quantiles portfolios by grouping stocks in the S&P 500 into Quantiles using one year historical Volatility. Next we will backtest each portfolio

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