add LF Gaussian/Lorentzian testing code.

src/external/LF_GL/CMakeLists.txt

@@ -0,0 +1,65 @@
+# - LF GL ---------------------------------------------------------------------
+
+cmake_minimum_required(VERSION 3.17)
+
+project(lf_gl VERSION 0.9 LANGUAGES C CXX)
+
+#--- set a default build type if none was specified ---------------------------
+set(default_build_type "Release")
+
+if (NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+  message(STATUS "Setting build type to '${default_build_type}' as none was specified.")
+  set(CMAKE_BUILD_TYPE "${default_build_type}" CACHE
+      STRING "Choose the type of build." FORCE)
+  # Set the possible values of build type for cmake-gui
+  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS
+    "Debug" "Release" "MinSizeRel" "RelWithDebInfo")
+endif ()
+
+#--- check for boost ----------------------------------------------------------
+find_package(Boost REQUIRED
+  COMPONENTS
+    system
+    filesystem
+)
+message(STATUS "Boost libs: ${Boost_LIBRARIES}")
+
+#--- check for gsl ------------------------------------------------------------
+find_package(GSL REQUIRED)
+
+#--- write summary of the installation
+cmake_host_system_information(RESULT PROCESSOR QUERY PROCESSOR_DESCRIPTION)
+
+message("")
+message("|-----------------------------------------------------------------------|")
+message("|                                                                       |")
+message("|                            Summary                                    |")
+message("|                                                                       |")
+message("|-----------------------------------------------------------------------|")
+message("")
+message(" System:    ${CMAKE_HOST_SYSTEM_NAME} ${CMAKE_SYSTEM_PROCESSOR} - ${CMAKE_HOST_SYSTEM_VERSION}")
+message(" Processor: ${PROCESSOR} (${CMAKE_SYSTEM_PROCESSOR})")
+message(" ----------")
+message("")
+message(" lf_gl Version: ${lf_gl_VERSION}")
+message(" --------------")
+message("")
+message(" Build Type: ${CMAKE_BUILD_TYPE}")
+message(" -----------")
+message("")
+message("-------------------------------------------------------------------------")
+message("")
+message(" GSL     found in ${GSL_INCLUDE_DIRS}, Version: ${GSL_VERSION}")
+message(" BOOST   found in ${Boost_INCLUDE_DIRS}, Version: ${Boost_VERSION}")
+message("")
+message("-------------------------------------------------------------------------")
+message("")
+
+add_executable(lf_gl main.cpp)
+set_property(TARGET lf_gl PROPERTY CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+target_include_directories(lf_gl 
+  BEFORE PRIVATE 
+    $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}>
+)
+target_link_libraries(lf_gl -lm GSL::gsl)