RcppExamples (version 0.1.10)

RcppRNGsExample: Rcpp RNGs example

Description

Rcpp sugar provides numerous p/q/d/r functions for numerous distributions.

This example shows (in the corresponding C++ code) how to draw from three different distributions and returns a data frame.

Author

Dirk Eddelbuettel and Romain Francois

Details

The various header file, and the Rcpp sugar vignette, provide full documentation for Rcpp sugar.

The C++ source file corresponding to the this function does the following:

        int n;  	// length passed in from R
        NumericVector rn = rnorm(n);
        NumericVector rt = rt(n, 1.0);
        NumericVector rp = rpois(n, 1.0);
        // create a new data frame to return drawns
       return DataFrame::create(Named("rnorm") = rn,
                                Named("rt")    = rt,
                                Named("rpois") = rp);
  

As shown in the example section, provided the seed is reset, the exact same draws can be obtained in R itself -- which is important for reproducibility.

Examples

  set.seed(42)
  X <- RcppRNGsExample(10L)
  set.seed(42)
  Y <- data.frame(rnorm=rnorm(10),rt=rt(10,1),rpois=rpois(10,1))
  all.equal(X,Y)