#includeusing Eigen::MatrixXd; int main() { MatrixXd mat(2,2); mat(0,0) = 1; mat(0,1) = 2; mat(1,0) = 3; mat(1,1) = 4; // access the first row of mat: auto row = mat.row(0); return 0; }
#includeIn this example, we create a 2x2 matrix `mat` and access its first row using the `row()` method. We then multiply each element of the row by 2 using the `*=` operator. The resulting matrix is then output to the console. Eigen is an open-source library and can be easily included in C++ code as a header-only library. The library is commonly referred to as the Eigen library.#include using Eigen::MatrixXd; int main() { MatrixXd mat(2,2); mat(0,0) = 1; mat(0,1) = 2; mat(1,0) = 3; mat(1,1) = 4; // access the first row of mat: auto row = mat.row(0); // multiply each element of the row by 2: row *= 2; std::cout << mat << std::endl; return 0; }