Eigen has been replaced with a rosdep system dependency. Electric also switched to Eigen 3. To migrate from Eigen2 to Eigen 3 see this guide

Electric: Porting to system dependency

Starting in ROS Electric, Eigen 3 is installed as a system dependency. This means that you compile against Eigen 3 without requiring any ROS-specific build tools.

CMakeLists.txt

For convenience, the system install includes CMake config files for easily finding and configuring Eigen in your CMakeLists.txt using the normal find_package() macro:

find_package(Eigen REQUIRED)
include_directories(${Eigen_INCLUDE_DIRS})

Eigen is a header-only library, so you do not need to specify any linking.

If you ever followed instructions on that wiki that told you to added your own FinEigen.cmake and add the following to your make cmake:

list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)

then you can revert those two changes. You probably also want to make sure that in the two lines above you wrote:

include_directories(${Eigen_INCLUDE_DIRS})

and not:

include_directories(${EIGEN_INCLUDE_DIRS})

Package/stack dependencies

Eigen is defined in the common_rosdeps stack/package. You will need to update

1. manifest.xml

     <depend package="common_rosdeps" />
     <rosdep name="eigen" />

2. stack.xml

     <depend stack="common_rosdeps" />

Documentation

Please see the Eigen homepage for documentation on the Eigen library. See also:

• Eigen API Documentation

• Eigen 2 to 3 conversion guide.

To help you get started with Eigen, we've put together an Eigen Cookbook.