eigen3

I have the following piece of code (I apologize for the slightly larger code snippet, this is the minimal example I was able to reduce my problem to): #include <Eigen/Dense> #include <complex> #include <iostream> #include <typeinfo> // Dynamic Matrix over Scalar field template <typename Scalar> using DynMat = Eigen::Matrix<Scalar, Eigen::Dynamic, Eigen::Dynamic>; // Dynamic column vector over Scalar field template <typename Scalar> using DynVect = Eigen::Matrix<Scalar, Eigen::Dynamic, 1>; // Returns the D x D Identity matrix over the field Derived::Scalar // deduced from the expression Eigen:

I have several feature vectors stored in a cv::Mat where, each row is a feature vector (several rows like this one here: [ x1 y1 x2 y2 x3 y3.... ] ). I have to apply SVD on each feature vector and for that I use Eigen library. But, before applying SVD the feature matrix has to be converted to Eigen::Matrix form. Later, I have to convert the SVD result back to cv::Mat . Could anyone please suggest a nice way to do this? The reason I need it in cv::Mat form is because I have to input it to a Neural Network in OpenCV and only cv::Mat inputs matrices are allowed. Thanks!!! Bull An example from

I am kind of desperate: For my studies I need to work with Eigen and CMake. I'm able to use Eigen if I copy the whole library in the directories where my compiler looks by default but as soon as I try to find it via find_package(Eigen3 REQUIRED) I get the following error: CMake Error at /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:148 (message): Could NOT find Eigen3 (missing: EIGEN3_INCLUDE_DIR EIGEN3_VERSION_OK) (Required is at least version "2.91.0") Call Stack (most recent call first): /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:388 (_FPHSA_FAILURE_MESSAGE)

Eigen has introduced the Ref<> class to write functions with Eigen objects as parameters without the use unnecessary temporaries, when writing template functions is not wanted. One can read about this here . When searching the internet further, I found several different declarations of parameters using the Ref<> class. In the Eigen documentation they use const Eigen::Ref<const Eigen::MatrixXf>& for a read-only parameter in the first example. In the second example Eigen::Ref<Eigen::MatrixXd> is introduced for read-and-write parameters, BUT here const Eigen::Ref<const Eigen::MatrixXd> is used