From 92190a1cafc3a8613e1200cd4ed81dbc509a93bd Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 7 Jan 2014 20:23:35 +0100
Subject: Add an example showing how to use C++11 random distributions

---
 Eigen/src/Core/CwiseNullaryOp.h       |  3 +++
 Eigen/src/Core/Random.h               |  2 ++
 doc/special_examples/CMakeLists.txt   | 19 +++++++++++++++++++
 doc/special_examples/random_cpp11.cpp | 14 ++++++++++++++
 4 files changed, 38 insertions(+)
 create mode 100644 doc/special_examples/random_cpp11.cpp

diff --git a/Eigen/src/Core/CwiseNullaryOp.h b/Eigen/src/Core/CwiseNullaryOp.h
index 1d4ee50a8..124383114 100644
--- a/Eigen/src/Core/CwiseNullaryOp.h
+++ b/Eigen/src/Core/CwiseNullaryOp.h
@@ -138,6 +138,9 @@ DenseBase<Derived>::NullaryExpr(Index rows, Index cols, const CustomNullaryOp& f
   *
   * The template parameter \a CustomNullaryOp is the type of the functor.
   *
+  * Here is an example with C++11 random generators: \include random_cpp11.cpp
+  * Output: \verbinclude random_cpp11.out
+  * 
   * \sa class CwiseNullaryOp
   */
 template<typename Derived>
diff --git a/Eigen/src/Core/Random.h b/Eigen/src/Core/Random.h
index a4492ddb6..fdd43ed0c 100644
--- a/Eigen/src/Core/Random.h
+++ b/Eigen/src/Core/Random.h
@@ -48,6 +48,8 @@ struct functor_traits<scalar_random_op<Scalar> >
   * a temporary matrix whenever it is nested in a larger expression. This prevents unexpected
   * behavior with expressions involving random matrices.
   * 
+  * See DenseBase::NullaryExpr(Index, const CustomNullaryOp&) for an example using C++11 random generators.
+  *
   * \sa DenseBase::setRandom(), DenseBase::Random(Index), DenseBase::Random()
   */
 template<typename Derived>
diff --git a/doc/special_examples/CMakeLists.txt b/doc/special_examples/CMakeLists.txt
index 0c9b3c3ba..45e2339e3 100644
--- a/doc/special_examples/CMakeLists.txt
+++ b/doc/special_examples/CMakeLists.txt
@@ -19,3 +19,22 @@ if(QT4_FOUND)
                      
   add_dependencies(all_examples Tutorial_sparse_example)
 endif(QT4_FOUND)
+
+check_cxx_compiler_flag("-std=c++11" EIGEN_COMPILER_SUPPORT_CPP11)
+if(EIGEN_COMPILER_SUPPORT_CPP11)
+  add_executable(random_cpp11 random_cpp11.cpp)
+  target_link_libraries(random_cpp11 ${EIGEN_STANDARD_LIBRARIES_TO_LINK_TO})
+  add_dependencies(all_examples random_cpp11)
+  ei_add_target_property(random_cpp11 COMPILE_FLAGS "-std=c++11")
+  
+  get_target_property(random_cpp11_exec
+                      random_cpp11 LOCATION)
+  add_custom_command(
+    TARGET random_cpp11
+    POST_BUILD
+    COMMAND ${random_cpp11_exec}
+    ARGS >${CMAKE_CURRENT_BINARY_DIR}/random_cpp11.out
+  )
+  
+  
+endif()
\ No newline at end of file
diff --git a/doc/special_examples/random_cpp11.cpp b/doc/special_examples/random_cpp11.cpp
new file mode 100644
index 000000000..ccd7c77d0
--- /dev/null
+++ b/doc/special_examples/random_cpp11.cpp
@@ -0,0 +1,14 @@
+#include <Eigen/Core>
+#include <iostream>
+#include <random>
+
+using namespace Eigen;
+
+int main() {
+  std::default_random_engine generator;
+  std::poisson_distribution<int> distribution(4.1);
+  auto poisson = [&] (int) {return distribution(generator);};
+
+  RowVectorXi v = RowVectorXi::NullaryExpr(10, poisson );
+  std::cout << v << "\n";
+}
-- 
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