* use transpose() instead of row vectors (more common use case)

* add a word about noalias and performance for BLAS users

doc/examples/tut_arithmetic_dot_cross.cpp

@@ -2,11 +2,14 @@
 #include <Eigen/Dense>
 
 using namespace Eigen;
+using namespace std;
 int main()
 {
   Vector3d v(1,2,3);
   Vector3d w(0,1,2);
 
-  std::cout << "Dot product: " << v.dot(w) << std::endl;
-  std::cout << "Cross product:\n" << v.cross(w) << std::endl;
+  cout << "Dot product: " << v.dot(w) << endl;
+  double dp = v.adjoint()*w; // automatic conversion of the inner product to a scalar
+  cout << "Dot product via a matrix product: " << dp << endl;
+  cout << "Cross product:\n" << v.cross(w) << endl;
 }