...

CMakeLists.txt

@@ -27,6 +27,12 @@ option(
     ON
 )
 
+option(
+    USE_EIGEN3
+    "Use of Eigen3 library as dependency for implemetation of PCM construction"
+    ON
+)
+
 option(USE_BSPLINE_PCM "Use of FITPACK bivariate splines for PCM" ON)
 
 option(
@@ -42,6 +48,27 @@ find_package(Threads REQUIRED)
 include(FetchContent)
 include(ExternalProject)
 
+# ******** Eigen3 LIBRARY *******
+
+if(USE_EIGEN3)
+    find_package(Eigen3 CONFIG)
+    if(TARGET Eigen3::Eigen)
+        message(STATUS "Eigen3 library was found!")
+    else()
+        message(STATUS \tfetch Eigen3 ...)
+        FetchContent_Declare(
+            eigen
+            GIT_REPOSITORY "https://gitlab.com/libeigen/eigen.git"
+            GIT_SHALLOW TRUE
+            GIT_PROGRESS TRUE
+            OVERRIDE_FIND_PACKAGE
+        )
+        FetchContent_MakeAvailable(eigen)
+
+        find_package(Eigen3 REQUIRED CONFIG)
+    endif()
+endif()
+
 # ******* SPDLOG LIBRARY *******
 
 if(USE_SPDLOG)
@@ -250,6 +277,10 @@ if(USE_BSPLINE_PCM)
     add_subdirectory(fitpack)
 endif()
 
+if(USE_EIGEN3)
+    list(APPEND MCC_SRC include/mcc/mcc_pcm_construct.h)
+endif()
+
 add_library(${PROJECT_NAME} INTERFACE ${MCC_SRC})
 target_compile_features(${PROJECT_NAME} INTERFACE cxx_std_23)
 target_include_directories(
@@ -272,6 +303,10 @@ if(USE_BSPLINE_PCM)
     )
 endif()
 
+if(USE_EIGEN3)
+    target_link_libraries(${PROJECT_NAME} INTERFACE Eigen3::Eigen)
+endif()
+
 if(USE_ASIO)
     target_link_libraries(${PROJECT_NAME} INTERFACE PkgConfig::ASIOLIB)
 endif()