I am trying to use ITK with an external Eigen build.
ITK was installed first in our server by the system analyst. Then I asked him if he could install Eigen.
I am making an application that uses ITK for reading and processing images and I need Eigen to compute some linear algebra stuff. However when I try to link Eigen libraries I get an error message.
This is the error message I get when I try to build the project. It seems it is looking for itkeigen…
/usr/local/include/eigen3/Eigen/src/Core/StlIterators.h:410:46: note: no functions named ‘typename Eigen::DenseBase<Derived>::iterator Eigen::DenseBase<Derived>::begin()’
In file included from /usr/local/include/ITK-5.2/itkeigen/Eigen/Core:440,
from /home/3484681/Área de Trabalho/scr (2)/teste202.cxx:1:
/usr/local/include/ITK-5.2/itkeigen/Eigen/src/Core/DenseBase.h:41:34: note: ‘class Eigen::DenseBase<Derived>’ defined here
41 | template<typename Derived> class DenseBase
Hi @Oddone-Scatena, the Eigen used in ITK is not mangled, so you cannot have a different external version of Eigen in your project. You have three options:
A) Use the internal Eigen used in ITK: for example #include <itkeigen/Eigen/Core> instead of the native #include <Eigen/Core>.
B) Build ITK with the Eigen version you want, or the one installed in your system. For that, you have to build ITK with the CMake flags: -DITK_USE_SYSTEM_EIGEN:BOOL=ON and point to it with -DEigen3_DIR:PATH=/path/eigen3/cmake. And then use that Eigen in your own code with: #include <Eigen/Core>
C) Another option, and this is the reason that ITK do not mangle Eigen is the following:
You can reuse the internal Eigen used in ITK, and still use the native includes, i.e. #include <Eigen/Core>. For that you need the following CMake code: