Reductions/Broadcasting/Visitor Tutorial added

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_visitors.cpp

@@ -0,0 +1,26 @@
+#include <iostream>
+#include <Eigen/Dense>
+
+using namespace std;
+using namespace Eigen;
+
+int main()
+{
+  Eigen::MatrixXf m(2,2);
+  
+  m << 1, 2,
+       3, 4;
+
+  //get location of maximum
+  MatrixXf::Index maxRow, maxCol;
+  float max = m.maxCoeff(&maxRow, &maxCol);
+
+  //get location of minimum
+  MatrixXf::Index minRow, minCol;
+  float min = m.minCoeff(&minRow, &minCol);
+
+  cout << "Max: " << max <<  ", at: " <<
+     maxRow << "," << maxCol << endl;
+  cout << "Min: " << min << ", at: " <<
+     minRow << "," << minCol << endl;
+}