Add a note on initParallel being optional in C++11.
diff --git a/doc/TopicMultithreading.dox b/doc/TopicMultithreading.dox
index 95f6bf2..47c9b26 100644
--- a/doc/TopicMultithreading.dox
+++ b/doc/TopicMultithreading.dox
@@ -43,6 +43,8 @@
}
\endcode
+\note With Eigen 3.3, and a fully C++11 compliant compiler (i.e., <a href="http://en.cppreference.com/w/cpp/language/storage_duration#Static_local_variables">thread-safe static local variable initialization</a>), then calling \c initParallel() is optional.
+
\warning note that all functions generating random matrices are \b not re-entrant nor thread-safe. Those include DenseBase::Random(), and DenseBase::setRandom() despite a call to Eigen::initParallel(). This is because these functions are based on std::rand which is not re-entrant. For thread-safe random generator, we recommend the use of boost::random or c++11 random feature.
In the case your application is parallelized with OpenMP, you might want to disable Eigen's own parallization as detailed in the previous section.