954 search results for "parallel"

Introducing RcppParallel: Getting R and C++ to work (some more) in parallel

July 16, 2014
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A common theme over the last few decades was that we could afford to simply sit back and let computer (hardware) engineers take care of increases in computing speed thanks to Moore's law. That same line of thought now frequently points out that we ar...

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Computing an Inner Product with RcppParallel

July 14, 2014
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Computing an Inner Product with RcppParallel

The RcppParallel package includes high level functions for doing parallel programming with Rcpp. For example, the parallelReduce function can be used aggreggate values from a set of inputs in parallel. This article describes using RcppParallel to parallelize the inner-product example previously posted to the Rcpp Gallery. Serial Version First the serial version of computing the inner product. For this we use a...

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Parallel Distance Matrix Calculation with RcppParallel

July 14, 2014
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Parallel Distance Matrix Calculation with RcppParallel

The RcppParallel package includes high level functions for doing parallel programming with Rcpp. For example, the parallelFor function can be used to convert the work of a standard serial “for” loop into a parallel one. This article describes using RcppParallel to compute pairwise distances for each row in an input data matrix and return an n x n lower-triangular distance matrix which...

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Implementing mclapply() on Windows: a primer on embarrassingly parallel computation on multicore systems with R

July 14, 2014
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An easy way to run R code in parallel on a multicore system is with the mclapply() function. Unfortunately, mclapply() does not work on Windows machines because the mclapply() implementation relies on forking and Windows does not support forking. For me, this is somewhat of a headache because I am used to using mclapply(), and

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Parallel computing in R

July 1, 2014
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Parallel computing in R

Roughly a year ago I published an article about parallel computing in R here, in which I compared computation performance among 4 packages that provide R with parallel features once R is essentially a single-thread task package. Parallel computing is incredibly useful, but not every thing worths distribute across as many cores as possible. Actually,

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Summing a Vector in Parallel with RcppParallel

June 28, 2014
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Summing a Vector in Parallel with RcppParallel

The RcppParallel package includes high level functions for doing parallel programming with Rcpp. For example, the parallelReduce function can be used aggreggate values from a set of inputs in parallel. This article describes using RcppParallel to sum an R vector. Serial Version First a serial version of computing the sum of a vector. For this we use a simple call to the STL std::accumulate function: #include...

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Transforming a Matrix in Parallel using RcppParallel

June 28, 2014
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Transforming a Matrix in Parallel using RcppParallel

The RcppParallel package includes high level functions for doing parallel programming with Rcpp. For example, the parallelFor function can be used to convert the work of a standard serial “for” loop into a parallel one. This article describes using RcppParallel to transform an R matrix in parallel. Serial Version First a serial version of the matrix transformation. We take the square root of each...

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sugar in parallel

June 18, 2014
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sugar in parallel

I've been playing with parallelising Rcpp11 implementation of sugar. For example, we have a NumericVector variable x and we want to compute e.g. sqrt(exp(x)) + 2.0. With sugar, we can do: NumericVector y = sqrt(exp(x)) + 2.0 ; and this does not...

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Rth: a Flexible Parallel Computation Package for R

June 17, 2014
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Rth:  a Flexible Parallel Computation Package for R

I’ve been mentioning here that I’ll be discussing a new package, Rth, developed by me and Drew Schmidt, the latter of pbdR fame.  It’s now ready for use!  In this post, I’ll explain what goals Rth has, and how to use it. Platform Flexibility The key feature of Rth is in the word flexible in

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Rth: a Flexible Parallel Computation Package for R

June 17, 2014
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Rth:  a Flexible Parallel Computation Package for R

I’ve been mentioning here that I’ll be discussing a new package, Rth, developed by me and Drew Schmidt, the latter of pbdR fame.  It’s now ready for use!  In this post, I’ll explain what goals Rth has, and how to use it. Platform Flexibility The key feature of Rth is in the word flexible in

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