Merge pull request #14 from rstudio/webinar/27-RcppParallel

Add RcppParallel webinar materials

Author: kevinushey

27-RcppParallel/.gitignore

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+.Rproj.user
+.Rhistory
+.RData
+.Ruserdata

27-RcppParallel/README.md

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+# RcppParallel
+
+This repository houses the materials used for the `RcppParallel` webinar delivered on August 31st, 2016.
+
+[Click here](https://rawgit.com/kevinushey/RcppParallel-webinar-2016/master/slides.html) to quickly preview the slides online.
+
+Visit the [RcppParallel webpage](https://rcppcore.github.io/RcppParallel/) to learn more!

27-RcppParallel/RcppParallel-user2016-talk.Rproj

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+Version: 1.0
+
+RestoreWorkspace: Default
+SaveWorkspace: Default
+AlwaysSaveHistory: Default
+
+EnableCodeIndexing: Yes
+UseSpacesForTab: Yes
+NumSpacesForTab: 2
+Encoding: UTF-8
+
+RnwWeave: Sweave
+LaTeX: pdfLaTeX
+
+AutoAppendNewline: Yes
+StripTrailingWhitespace: Yes

27-RcppParallel/RcppParallelExample/.Rbuildignore

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+^.*\.Rproj$
+^\.Rproj\.user$
+^internal/

27-RcppParallel/RcppParallelExample/.gitignore

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+.Rproj.user
+.Rhistory
+.RData
+src/*.o
+src/*.so
+

27-RcppParallel/RcppParallelExample/DESCRIPTION

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+Package: RcppParallelExample
+Title: An Example Package Leveraging RcppParallel
+Version: 1.0.0
+Author: Kevin Ushey
+Maintainer: Kevin Ushey <[email protected]>
+Description: An R package that showcases how RcppParallel can be
+    used to implement algorithms that perform their computations
+    in parallel.
+Depends:
+    R (>= 3.2.0)
+Imports:
+    Rcpp,
+    RcppParallel
+LinkingTo: Rcpp, RcppParallel
+SystemRequirements: GNU make
+License: GPL (>= 2)
+Encoding: UTF-8
+LazyData: true
+RoxygenNote: 5.0.1

27-RcppParallel/RcppParallelExample/NAMESPACE

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+# A dummy pattern that ensures all functions not beginning with a '.'
+# are exported -- ie, made available to users when they call
+# library(RcppParallelExample). We use this to ensure that our
+# 'parallelInnerProduct()' and 'parallelLog()' functions are both
+# exported.
+exportPattern("^[^\\.]")
+
+# We must ensure that at least one function is imported from the
+# RcppParallel package; otherwise you may see strange linker errors
+# on package build; for example:
+#
+#     Symbol not found: __ZN3tbb4task13note_affinityEt
+#
+importFrom(RcppParallel, RcppParallelLibs)
+importFrom(Rcpp, evalCpp)
+
+# This directive lets R know that this package produces a shared
+# object called 'RcppParallelExample.so', and that the symbols
+# within should be made available to R functions within the package.
+useDynLib(RcppParallelExample)

27-RcppParallel/RcppParallelExample/R/RcppExports.R

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+# This file was generated by Rcpp::compileAttributes
+# Generator token: 10BE3573-1514-4C36-9D1C-5A225CD40393
+
+#' Parallel Inner Product
+#'
+#' Compute the inner product of two numeric vectors.
+#'
+#' @param lhs,rhs Numeric vectors.
+#' @export
+parallelInnerProduct <- function(lhs, rhs) {
+    .Call('RcppParallelExample_parallelInnerProduct', PACKAGE = 'RcppParallelExample', lhs, rhs)
+}
+
+#' Parallel Log
+#'
+#' Compute the natural log of a numeric vector.
+#'
+#' @param input A numeric vector.
+#' @export
+parallelLog <- function(input) {
+    .Call('RcppParallelExample_parallelLog', PACKAGE = 'RcppParallelExample', input)
+}
+

27-RcppParallel/RcppParallelExample/RcppParallelExample.Rproj

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+Version: 1.0
+
+RestoreWorkspace: No
+SaveWorkspace: No
+AlwaysSaveHistory: Default
+
+EnableCodeIndexing: Yes
+UseSpacesForTab: Yes
+NumSpacesForTab: 4
+Encoding: UTF-8
+
+RnwWeave: Sweave
+LaTeX: pdfLaTeX
+
+AutoAppendNewline: Yes
+StripTrailingWhitespace: Yes
+
+BuildType: Package
+PackageUseDevtools: Yes
+PackageInstallArgs: --no-multiarch --with-keep.source
+PackageRoxygenize: rd,collate

27-RcppParallel/RcppParallelExample/internal/internal-examples.R

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+library(RcppParallelExample)
+library(microbenchmark)
+
+# A simple R example for computation of the inner product.
+innerProduct <- function(lhs, rhs) {
+    sum(lhs * rhs)
+}
+
+# Generate 10 x 2 million random numbers, for a simple benchmark.
+set.seed(123)
+lhs <- rnorm(1E7)
+rhs <- rnorm(1E7)
+
+# Confirm that our R implementation, as well as our RcppParallel
+# implementation, produce the same results.
+all.equal(
+    innerProduct(lhs, rhs),
+    parallelInnerProduct(lhs, rhs)
+)
+
+# Compare performance!
+microbenchmark(
+    R = innerProduct(lhs, rhs),
+    Rcpp = parallelInnerProduct(lhs, rhs)
+)