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compilationcmakeeigen

Cmake finds Eigen library but does not mark with found

I found a strange behavior with cmake. On my computer I have two versions of Eigen:

  1. installed one via ubuntu repo (version 3.2.2)
  2. downloaded one (version 3.3.3).

I have added the location of the 2. Eigen library in $PATH.

In the CMakeFiles.txt I write

find_package(Eigen3 3.3.3 REQUIRED)
if (NOT Eigen3_FOUND)
MESSAGE( STATUS "Eigen not found.")
endif(NOT Eigen3_FOUND)
MESSAGE( STATUS "EIGEN_DIR:         " ${Eigen3_INCLUDE_DIR})

but it outputs the following:

-- Found Eigen3: /home/armena/armena/eigen3 (Required is at least version "3.3.3") 
-- Eigen not found.
-- EIGEN_DIR:

From what I understand it finds the library but it is not able to return its location. Any idea how to fix this? Thanks

Solution

  • The problem is that Eigen's package config file does not follow CMake's recommended naming guidelines; all of its variables are prefixed with EIGEN3_, not with Eigen3_. If you change your CMakeList like this, it should work:

    if (NOT EIGEN3_FOUND)
  message( STATUS "Eigen not found.")
endif()
message( STATUS "EIGEN_DIR:         " ${EIGEN3_INCLUDE_DIR})