Modified Array Class tutorial, added examples

doc/examples/Tutorial_ArrayClass_interop.cpp

@@ -0,0 +1,38 @@
+#include <Eigen/Dense>
+#include <iostream>
+
+using namespace Eigen;
+using namespace std;
+
+int main()
+{
+  MatrixXf m(2,2);
+  MatrixXf n(2,2);
+  
+  MatrixXf result(2,2);
+
+  //initialize matrices
+  m << 1,2,
+       3,4;
+
+  n << 5,6,
+       7,8;
+  
+  // mix of array and matrix operations
+  //   first coefficient-wise addition
+  //   then the result is used with matrix multiplication
+  result = (m.array() + 4).matrix() * m;
+
+  cout << "-- Combination 1: --" << endl
+    << result << endl << endl;
+
+
+  // mix of array and matrix operations
+  //   first coefficient-wise multiplication
+  //   then the result is used with matrix multiplication
+  result = (m.array() * n.array()).matrix() * m;
+
+  cout << "-- Combination 2: --" << endl
+    << result << endl << endl;
+
+}