do not trigger rand() use warning in skeleton (closes #69)

Author: eddelbuettel

ChangeLog

@@ -1,3 +1,8 @@
+2019-03-29  Dirk Eddelbuettel  <edd@debian.org>
+
+	* inst/skeleton/rcppeigen_hello_world.cpp: Rework first example to
+	not rely on Eigen RNG which R CMD check would complain about.
+
 2019-02-16  James Joseph Balamuta <balamut2@illinois.edu>
 
 	* R/runit.RcppEigen.R: Removed listing RcppEigen in Imports during

inst/skeleton/rcppeigen_hello_world.cpp

@@ -17,13 +17,18 @@
 // [[Rcpp::export]]
 Eigen::MatrixXd rcppeigen_hello_world() {
     Eigen::MatrixXd m1 = Eigen::MatrixXd::Identity(3, 3);
-    Eigen::MatrixXd m2 = Eigen::MatrixXd::Random(3, 3);
-	                     
+    // Eigen::MatrixXd m2 = Eigen::MatrixXd::Random(3, 3);
+    // Do not use Random() here to not promote use of a non-R RNG
+    Eigen::MatrixXd m2 = Eigen::MatrixXd::Zero(3, 3);
+    for (auto i=0; i<m2.rows(); i++)
+        for (auto j=0; j<m2.cols(); j++)
+            m2(i,j) = R::rnorm(0, 1);
+
     return m1 + 3 * (m1 + m2);
 }
 
 
-// another simple example: outer product of a vector, 
+// another simple example: outer product of a vector,
 // returning a matrix
 //
 // [[Rcpp::export]]