#includeEigen::MatrixXd mat(3,3); // create a 3x3 matrix mat << 1, 2, 3, 4, 5, 6, 7, 8, 9; // populate the matrix Eigen::VectorXd row = mat.row(1); // get the second row
#includeEigen::MatrixXd mat(3,3); // create a 3x3 matrix mat << 1, 2, 3, 4, 5, 6, 7, 8, 9; // populate the matrix Eigen::MatrixXd rows = mat.block(0, 0, 2, 3); // get the first two rows
#includeIn this example, we create a 3x3 matrix and fill it with values. We then use the row() method to modify the first row and set it to a vector of all ones. All of these examples make use of the Eigen library in C++.Eigen::MatrixXd mat(3,3); // create a 3x3 matrix mat << 1, 2, 3, 4, 5, 6, 7, 8, 9; // populate the matrix mat.row(0) = Eigen::VectorXd::Ones(3); // set the first row to all ones