[Rcpp-commits] r3010 - pkg/RcppArmadillo/inst/examples

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

Author: edd
Date: 2011-04-23 18:18:09 +0200 (Sat, 23 Apr 2011)
New Revision: 3010

Modified:
   pkg/RcppArmadillo/inst/examples/varSimulation.r
Log:
reordered slightly


Modified: pkg/RcppArmadillo/inst/examples/varSimulation.r
===================================================================
--- pkg/RcppArmadillo/inst/examples/varSimulation.r	2011-04-23 15:37:46 UTC (rev 3009)
+++ pkg/RcppArmadillo/inst/examples/varSimulation.r	2011-04-23 16:18:09 UTC (rev 3010)
@@ -19,8 +19,35 @@
 ## You should have received a copy of the GNU General Public License
 ## along with RcppArmadillo.  If not, see <http://www.gnu.org/licenses/>.
 
+
+## parameter and error terms used throughout
+a <- matrix(c(0.5,0.1,0.1,0.5),nrow=2)
+e <- matrix(rnorm(10000),ncol=2)
+
+
+## Let's start with the R version
+rSim <- function(coeff, errors) {
+  simdata <- matrix(0, nrow(errors), ncol(errors))
+  for (row in 2:nrow(errors)) {
+    simdata[row,] = coeff %*% simdata[(row-1),] + errors[row,]
+  }
+  return(simdata)
+}
+
+rData <- rSim(a, e)                     # generated by R
+
+
+## Now let's load the R compiler (requires R 2.13 or later)
+suppressMessages(require(compiler))
+compRsim <- cmpfun(rSim)
+
+compRData <- compRsim(a,e)              # generated by R 'compiled'
+
+stopifnot(all.equal(rData, compRData))  # checking results
+
+
+## Now load 'inline' to compile C++ code on the fly
 suppressMessages(require(inline))
-
 code <- '
   arma::mat coeff = Rcpp::as<arma::mat>(a);
   arma::mat errors = Rcpp::as<arma::mat>(e);
@@ -33,29 +60,15 @@
   return Rcpp::wrap(simdata);
 '
 
+## create the compiled function
 rcppSim <- cxxfunction(signature(a="numeric",e="numeric"),
                        code,plugin="RcppArmadillo")
 
-a <- matrix(c(0.5,0.1,0.1,0.5),nrow=2)
-e <- matrix(rnorm(10000),ncol=2)
-rcppData <- rcppSim(a,e)
+rcppData <- rcppSim(a,e)                # generated by C++ code
 
-rSim <- function(coeff,errors) {
-  simdata <- matrix(0,nrow(errors),ncol(errors))
-  for (row in 2:nrow(errors)) {
-    simdata[row,] = coeff %*% simdata[(row-1),] + errors[row,]
-  }
-  return(simdata)
-}
-rData <- rSim(a,e)
-stopifnot(all.equal(rcppData, rData))
+stopifnot(all.equal(rData, rcppData))   # checking results
 
-suppressMessages(require(compiler))
-compRsim <- cmpfun(rSim)
-
-compRData <- compRsim(a,e)
-stopifnot(all.equal(rcppData, compRData))
-
+## now load the rbenchmark package and compare all three
 library(rbenchmark)
 res <- benchmark(rcppSim(a,e),
                  rSim(a,e),