Reductions/Broadcasting/Visitor Tutorial added

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_broadcast_1nn.cpp

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+#include <iostream>
+#include <Eigen/Dense>
+
+using namespace std;
+using namespace Eigen;
+
+int main()
+{
+  Eigen::MatrixXf m(2,4);
+  Eigen::VectorXf v(2);
+  
+  m << 1, 23, 6, 9,
+       3, 11, 7, 2;
+       
+  v << 2,
+       3;
+
+  MatrixXf::Index index;
+  // find nearest neighbour
+  (m.colwise() - v).colwise().squaredNorm().minCoeff(&index);
+
+  cout << "Nearest neighbour is column " << index << ":" << endl;
+  cout << m.col(index) << endl;
+}

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_broadcast_1nn.cpp~

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+#include <iostream>
+#include <Eigen/Dense>
+
+using namespace std;
+using namespace Eigen;
+
+int main()
+{
+  Eigen::MatrixXf m(2,4);
+  Eigen::VectorXf v(2);
+  
+  m << 1, 2, 6, 9,
+       3, 1, 7, 2;
+       
+  v << 2,
+       3;
+
+  MatrixXf::Index index;
+  // find nearest neighbour
+  (m.colwise() - v).colwise().squaredNorm().minCoeff(&index);
+
+  cout << "Nearest neighbour is column " << index << ":" << endl;
+  cout << m.col(index) << endl;
+}

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_broadcast_simple.cpp

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+#include <iostream>
+#include <Eigen/Dense>
+
+using namespace std;
+int main()
+{
+  Eigen::MatrixXf mat(2,4);
+  Eigen::VectorXf v(2);
+  
+  mat << 1, 2, 6, 9,
+         3, 1, 7, 2;
+         
+  v << 0,
+       1;
+       
+  //add v to each column of m
+  mat.colwise() += v;
+  
+  std::cout << "Broadcasting result: " << std::endl;
+  std::cout << mat << std::endl;
+}

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_broadcast_simple.cpp~

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+#include <iostream>
+#include <Eigen/Dense>
+
+using namespace std;
+int main()
+{
+  Eigen::MatrixXf mat(2,4);
+  Eigen::MatrixXf v(2);
+  
+  mat << 1, 2, 6, 9,
+         3, 1, 7, 2;
+         
+  v << 0,
+       1;
+       
+  //add v to each column of m
+  mat.colwise() += v;
+  
+  std::cout << "Broadcasting result: " << std::endl;
+  std::cout << mat << std::endl;
+}

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_broadcast_simple_rowwise.cpp

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+#include <iostream>
+#include <Eigen/Dense>
+
+using namespace std;
+int main()
+{
+  Eigen::MatrixXf mat(2,4);
+  Eigen::VectorXf v(4);
+  
+  mat << 1, 2, 6, 9,
+         3, 1, 7, 2;
+         
+  v << 0,1,2,3;
+       
+  //add v to each row of m
+  mat.rowwise() += v;
+  
+  std::cout << "Broadcasting result: " << std::endl;
+  std::cout << mat << std::endl;
+}

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_colwise.cpp

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+#include <iostream>
+#include <Eigen/Dense>
+
+using namespace std;
+int main()
+{
+  Eigen::MatrixXf mat(2,4);
+  mat << 1, 2, 6, 9,
+         3, 1, 7, 2;
+  
+  std::cout << "Column's maximum: " << std::endl
+   << mat.colwise().maxCoeff() << std::endl;
+}

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_maxnorm.cpp

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+#include <iostream>
+#include <Eigen/Dense>
+
+using namespace std;
+int main()
+{
+  Eigen::MatrixXf mat(2,4);
+  mat << 1, 2, 6, 9,
+         3, 1, 7, 2;
+  
+  int   maxIndex;
+  float maxNorm = mat.colwise().sum().maxCoeff(&maxIndex);
+  
+  std::cout << "Maximum sum at position " << maxIndex << std::endl;
+
+  std::cout << "The corresponding vector is: " << std::endl;
+  std::cout << mat.col( maxIndex ) << std::endl;
+  std::cout << "And its sum is is: " << maxNorm << std::endl;
+}

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_rowwise.cpp

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+#include <iostream>
+#include <Eigen/Dense>
+
+using namespace std;
+int main()
+{
+  Eigen::MatrixXf mat(2,4);
+  mat << 1, 2, 6, 9,
+         3, 1, 7, 2;
+  
+  std::cout << "Row's maximum: " << std::endl
+   << mat.rowwise().maxCoeff() << std::endl;
+}

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_visitors.cpp

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+#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;
+}

doc/examples/Tutorial_ReductionsVisitorsBroadcasting_visitors.cpp~

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+#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;
+  m.maxCoeff(&maxRow, &maxCol);
+
+  //get location of minimum
+  MatrixXf::Index minRow, minCol;
+  m.minCoeff(&minRow, &minCol);
+
+  cout << "Max at: " <<
+     maxRow << "," << maxCol << endl;
+  cout << "Min at: " <<
+     minRow << "," << minCol << endl;
+}