improvements in tutorial page 4 : block operations

3 files changed, 23 insertions, 18 deletions

diff --git a/doc/examples/Tutorial_BlockOperations_block_assignment.cpp b/doc/examples/Tutorial_BlockOperations_block_assignment.cpp
index 56ca69a6e..76f49f2fb 100644
--- a/doc/examples/Tutorial_BlockOperations_block_assignment.cpp
+++ b/doc/examples/Tutorial_BlockOperations_block_assignment.cpp
@@ -6,13 +6,13 @@ using namespace Eigen;
 
 int main()
 {
-  Array33f m;
-  m << 1,2,3,
-       4,5,6,
-       7,8,9;
-  Array<float,5,5> n = Array<float,5,5>::Constant(0.6);
-  n.block(1,1,3,3) = m;
-  cout << "n = " << endl << n << endl << endl;
-  Array33f res = n.block(0,0,3,3) * m;
-  cout << "res =" << endl << res << endl;
+  Array22f m;
+  m << 1,2,
+       3,4;
+  Array44f a = Array44f::Constant(0.6);
+  cout << "Here is the array a:" << endl << a << endl << endl;
+  a.block<2,2>(1,1) = m;
+  cout << "Here is now a with m copied into its central 2x2 block:" << endl << a << endl << endl;
+  a.block(0,0,2,3) = a.block(2,1,2,3);
+  cout << "Here is now a with bottom-right 2x3 block copied into top-left 2x2 block:" << endl << a << endl << endl;
 }
diff --git a/doc/examples/Tutorial_BlockOperations_colrow.cpp b/doc/examples/Tutorial_BlockOperations_colrow.cpp
index e98263057..2e7eb009b 100644
--- a/doc/examples/Tutorial_BlockOperations_colrow.cpp
+++ b/doc/examples/Tutorial_BlockOperations_colrow.cpp
@@ -1,14 +1,17 @@
 #include <Eigen/Dense>
 #include <iostream>
 
+using namespace std;
+
 int main()
 {
   Eigen::MatrixXf m(3,3);
   m << 1,2,3,
        4,5,6,
        7,8,9;
-  std::cout << "2nd Row: " << m.row(1) << std::endl;
-  m.col(0) += m.col(2);
-  std::cout << "m after adding third column to first:\n";
-  std::cout << m << std::endl;
+  cout << "Here is the matrix m:" << endl << m << endl;
+  cout << "2nd Row: " << m.row(1) << endl;
+  m.col(2) += 3 * m.col(0);
+  cout << "After adding 3 times the first column into the third column, the matrix m is:\n";
+  cout << m << endl;
 }
diff --git a/doc/examples/Tutorial_BlockOperations_print_block.cpp b/doc/examples/Tutorial_BlockOperations_print_block.cpp
index 0fdefecdf..edea4aefe 100644
--- a/doc/examples/Tutorial_BlockOperations_print_block.cpp
+++ b/doc/examples/Tutorial_BlockOperations_print_block.cpp
@@ -1,6 +1,8 @@
 #include <Eigen/Dense>
 #include <iostream>
 
+using namespace std;
+
 int main()
 {
   Eigen::MatrixXf m(4,4);
@@ -8,11 +10,11 @@ int main()
         5, 6, 7, 8,
         9,10,11,12,
        13,14,15,16;
-  std::cout << "Block in the middle" << std::endl;
-  std::cout << m.block<2,2>(1,1) << std::endl << std::endl;
-  for (int i = 1; i < 4; ++i) 
+  cout << "Block in the middle" << endl;
+  cout << m.block<2,2>(1,1) << endl << endl;
+  for (int i = 1; i <= 3; ++i)
   {
-    std::cout << "Block of size " << i << std::endl;
-    std::cout << m.block(0,0,i,i) << std::endl << std::endl;
+    cout << "Block of size " << i << "x" << i << endl;
+    cout << m.block(0,0,i,i) << endl << endl;
   }
 }