Tagged Questions

R is a free, open source programming language and software environment for statistical computing and graphics.

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0
votes
1answer
73 views

Learning R – repeated measures simulator optimisation

I am learning to program in R and to do that and create something useful in the process, I have decided to rewrite this Java applet for repeated measures simulation and to implement some new ...
2
votes
1answer
61 views

Vectorize or otherwise speed up a double for loop

I have this function containing some loops and a double for loop. What it does is set up a matrix first to store results in (the task at hand is comparing genomes) and then with sliding window, ...
0
votes
1answer
41 views

Which components of this r loop are inefficient?

I realize that there is a surfeit of posts on SE/SO about optimizing one's R for() loops. I'm afraid, though, that I don't understand all of the guidance in the answers there, or how to apply their ...
3
votes
1answer
57 views

More elegant filter script in R

I'm very new both to programming and to R so please bear with me :-) I've written the following bit of code, which works perfectly well and runs through a data file with 17446 rows in about 35 ...
1
vote
2answers
78 views

Is this correct R? remove first duplicate dataframe

I have a dataframe with several columns. One of them is an user id column, in this column, I have several ids that can be repeated several times. What I want to do is remove the first id, for ...
2
votes
0answers
90 views

Speed up a monte carlo simulation with nested loop

I would like to know if there is a more efficiency way to speed up below code. It uses a procedure where subsampling is required in the nested loop (which a previous answer ...
3
votes
1answer
60 views

Compute intersections of all combinations of vectors in a list of vectors in R

My goal is to compute the intersections of several vectors (sets of identifiers, gene-names to be specific). I start with a list of vectors and run the function below, which loops through 1:n where n ...
2
votes
1answer
95 views

Increase efficiency for an R simulator of the Monty Hall Puzzle

The Monty Hall Problem is a simple puzzle involving probability that even stumps professionals in careers dealing with some heavy-duty math. Here's the basic problem: Suppose you're on a game show, ...
3
votes
2answers
42 views

Speeding up for-loop over a list

I have two lists with ca. 4000 elements where each each element have two columns. These are being fed into a function. Besides the function they are being fed into, is it possible to speed it up ...
2
votes
1answer
111 views

R code is slow on filling a matrix

I am running an R code, which is implementing a Markov Chain Monte Carlo algorithm for updating a density distribution There is a specific section of my code which tries to fill a very large matrix ...
1
vote
1answer
90 views

Speed up a sampling function

I have the following dataset kkk<-data.frame(days=1:100,positive=rbinom(100,1,0.05)) Over the monitoring period of 100 days, if an event occurs then for that day kkk$positive==1 else ...
2
votes
1answer
69 views

How do I speed up the following R code?

I have files containing data set which contain 11,000 rows. I have to run a loop through each row, this is taking me 25minutes for each file. I am using following code: z <- ...
1
vote
1answer
103 views

increase speed for 'for loop'

I have files containing data set which contain 11,000 rows. I have to run a loop through each row, this is taking me 25minutes for each file. I am using following code: z <- read.zoo("Title.txt", ...
3
votes
2answers
137 views

How would you improve this code in R?

I'm trying to implement a function that given a data frame returns the same data frame with four columns added. These new four columns are: for each row, I get the maximun element and its index and ...
1
vote
1answer
211 views

Improving R script performance

i am having some performance problems with a little R script of mine that I use to visualize simulation results of a project of ( mine ). It now takes longer on my machine to run the R script than the ...
3
votes
2answers
90 views

Improving R code - remove redundant if's and assignments

I've written this brief function, it's to do with calculating which calendar year a student would be in Year 1 based on their DOB. In 1998 there was a change in the DOB cut points for starting Year 1, ...
0
votes
1answer
295 views

Optimize C++ Code

I have the following C++ function which I'd like to speed up, if possible. This program will have many different users, so parallelization is not really an option. The C++ function is wrapped by C ...
5
votes
2answers
350 views

My R code runs very slowly, how to improve?

I wrote the following code in R, basically I want to convert all categorical column in a R dataframe to several binary columns: for example, a categorical column like Company ------- IBM Microsoft ...
1
vote
0answers
111 views

Can anyone speed up this R function?

This script fetches a list of "end-positions" from a MYSQL database. The positions are array positions that are the same in both MYSQL and R. Next, the script takes the previous 34 elements for each ...
3
votes
1answer
296 views

Generate graph in Matlab

I use this Matlab code: load ~/emailAnalysis/results.txt results=results(size(results,1)-400:size(results,1),:) temp = results(:,3)-1238370000; h=plot(temp,smooth(results(:,1)),':b') ...
1
vote
1answer
48 views

Is there a more efficient way to simulate in R, by exposition factor, gender and disease profile?

I started working with R recently and need to do a simulation for 100 000 people that divides them in exposition factor for a disease, gender and presence or absence of disease. My background info is ...
3
votes
1answer
112 views

What is the best approach to use in R and why?

I'm starting working with R, and found some tutorials and exercises online. I want to divide one variable in two, bigger and equal 79 and smaller 79. Perhaps because I'm used to python, my first ...
4
votes
3answers
159 views

Is there a better way to get the index of a minimum?

Consider the following reproducible example: # note that lh is a standard ts dataset that ships with R lh # fit an R model ar.mle<-ar(lh,method="mle") # now get the min AIC, this is the ...
3
votes
1answer
119 views

How can I get this R code to pass the “1 minute” test for this Project Euler question?

I am attempting to learn R programming by going through the questions in Project Euler. The code below is my solution to problem 5 which asks for the smallest number that is evenly divisible by 1 ...
1
vote
0answers
158 views

Making this code more R-like

I've written the code below to do some work on machine learning in R. I'm not overly happy with some bits of it, and I suspect I could improve it quite a bit. Bits I'm specifically interested in ...
3
votes
2answers
541 views

How to simplify nested conditional for loop in R?

I have this for loop for creating a list of variables: vars <- c( 'beta.o', 'sd.y') for (x in c('ghs', 'site', 'trt')) { if(model.parms[[x]] == 1) { data <- data[, which(names(data) != ...