[Rcpp-commits] r4006 - in pkg/Rcpp: . inst inst/examples/Misc

[noreply at r-forge.r-project.org]

Author: edd
Date: 2012-11-21 13:46:44 +0100 (Wed, 21 Nov 2012)
New Revision: 4006

Added:
   pkg/Rcpp/inst/examples/Misc/piBySimulation.r
   pkg/Rcpp/inst/examples/Misc/piSugar.cpp
Modified:
   pkg/Rcpp/ChangeLog
   pkg/Rcpp/inst/NEWS.Rd
Log:
added 'pi by Simulation' example


Modified: pkg/Rcpp/ChangeLog
===================================================================
--- pkg/Rcpp/ChangeLog	2012-11-21 10:35:38 UTC (rev 4005)
+++ pkg/Rcpp/ChangeLog	2012-11-21 12:46:44 UTC (rev 4006)
@@ -1,3 +1,9 @@
+2012-11-21  Dirk Eddelbuettel  <edd at debian.org>
+
+	* inst/examples/Misc/piBySimulation.r: New simple example using Rcpp
+	attributes in a 'compute pi by simulation in R and C++' exercise
+	* inst/examples/Misc/piSugar.cpp: Corresponding C++ variant
+
 2012-11-21  Romain Francois <romain at r-enthusiasts.com>
 
         * include/Rcpp/iostream/Rostream.h: Fix warning given by -Wreorder
@@ -10,12 +16,12 @@
 
 2012-11-20  Romain Francois <romain at r-enthusiasts.com>
 
-        * include/Rcpp/iostream/Rostream.h: change order of initiaization in 
-        ctor. was making solaris compiler unhappy
+        * include/Rcpp/iostream/Rostream.h: change order of initiaization in
+	ctor. was making solaris compiler unhappy
         * include/Rcpp/stats/random/rnorm.h: not using function pointer
-        generators, as this generates (anachronisms) warning on solaris. Also, 
-        this version is more efficient since there is no need to dereference
-        the function pointer
+	generators, as this generates (anachronisms) warning on
+	solaris. Also, this version is more efficient since there is no need
+	to dereference the function pointer
 
 2012-11-19  JJ Allaire <jj at rstudio.org>
 
@@ -30,8 +36,8 @@
 
 2012-11-18  JJ Allaire <jj at rstudio.org>
 
-        * R/Attributes.R: sourceCpp embedded R code; print warning if 
-        no export attributes are found in source file
+        * R/Attributes.R: sourceCpp embedded R code; print warning if no
+	export attributes are found in source file
         * src/AttributesParser.h: sourceCpp embedded R code
         * src/AttributesParser.cpp: sourceCpp embedded R code; new scheme
         for mixing user and generated C++ headers

Modified: pkg/Rcpp/inst/NEWS.Rd
===================================================================
--- pkg/Rcpp/inst/NEWS.Rd	2012-11-21 10:35:38 UTC (rev 4005)
+++ pkg/Rcpp/inst/NEWS.Rd	2012-11-21 12:46:44 UTC (rev 4006)
@@ -6,7 +6,7 @@
     \itemize{
         \item Changes in Rcpp sugar: 
         \itemize{
-            \item New functions: \code{setdiff}, \code{union_}, \code{intersect}
+          \item New functions: \code{setdiff}, \code{union_}, \code{intersect}
             \code{setequal}, \code{in}, \code{min}, \code{max}, \code{range}, 
             \code{match}
         }
@@ -31,6 +31,10 @@
         \itemize{
             \item New function \code{areMacrosDefined}    
         }
+        \item Miscellaneous changes:
+        \itemize{
+          \item New example 'pi simulation' using R and C++ via Rcpp attributes
+	}
     }
 }
 \section{Changes in Rcpp version 0.10.0 (2012-11-13)}{

Added: pkg/Rcpp/inst/examples/Misc/piBySimulation.r
===================================================================
--- pkg/Rcpp/inst/examples/Misc/piBySimulation.r	                        (rev 0)
+++ pkg/Rcpp/inst/examples/Misc/piBySimulation.r	2012-11-21 12:46:44 UTC (rev 4006)
@@ -0,0 +1,28 @@
+#!/usr/bin/r
+
+library(Rcpp)
+library(rbenchmark)
+
+piR <- function(N) {
+    x <- runif(N)
+    y <- runif(N)
+    d <- sqrt(x^2 + y^2)
+    return(4 * sum(d < 1.0) / N)
+}
+
+sourceCpp("piSugar.cpp")
+
+N <- 1e6
+
+set.seed(42)
+resR <- piR(N)
+
+set.seed(42)
+resCpp <- piSugar(N)
+
+## important: check results are identical with RNG seeded
+stopifnot(identical(resR, resCpp))
+
+res <- benchmark(piR(N), piSugar(N), order="relative")
+
+print(res[,1:4])


Property changes on: pkg/Rcpp/inst/examples/Misc/piBySimulation.r
___________________________________________________________________
Added: svn:executable
   + *

Added: pkg/Rcpp/inst/examples/Misc/piSugar.cpp
===================================================================
--- pkg/Rcpp/inst/examples/Misc/piSugar.cpp	                        (rev 0)
+++ pkg/Rcpp/inst/examples/Misc/piSugar.cpp	2012-11-21 12:46:44 UTC (rev 4006)
@@ -0,0 +1,13 @@
+
+#include <Rcpp.h>
+
+using namespace Rcpp;
+
+// [[Rcpp::export]]
+double piSugar(const int N) {
+  RNGScope scope;		// ensure RNG gets set/reset
+  NumericVector x = runif(N);
+  NumericVector y = runif(N);
+  NumericVector d = sqrt(x*x + y*y);
+  return 4.0 * sum(d < 1.0) / N;
+}