External Project Integration

Table of Contents

• Makefile integration
• CMake integration
  • Sub-directory
  • FetchContent
  • find_package

Makefile integration

NEML2 officially supports GNU Make integration via pkg-config.

After installing NEML2, point PKG_CONFIG_PATH to the directory containing neml2.pc (typically <prefix>/share/pkgconfig), then query compile and link flags from pkg-config.

The following example Makefile compiles a program named foo from main.cxx:

CXX ?= c++
PKG_CONFIG ?= pkg-config
 
TARGET := foo
SOURCES := main.cxx
comma := ,
 
CXXFLAGS += $(shell $(PKG_CONFIG) --cflags neml2)
LDFLAGS += $(foreach libdir,$(shell $(PKG_CONFIG) --libs-only-L neml2),$(patsubst -L%,-Wl$(comma)-rpath$(comma)%,$(libdir)))
LDLIBS += $(shell $(PKG_CONFIG) --libs neml2)
 
.PHONY: all clean
 
all: $(TARGET)
 
$(TARGET): $(SOURCES)
    $(CXX) $(CXXFLAGS) $(LDFLAGS) -o $@ $(SOURCES) $(LDLIBS)
 
clean:
    rm -f $(TARGET)

Example usage:

PKG_CONFIG_PATH=/path/to/neml2-install/share/pkgconfig make
./foo

CMake integration

Sub-directory

Integrating NEML2 into a project that already uses CMake is fairly straightforward. The following CMakeLists.txt snippet links NEML2 into the target executable called foo:

add_subdirectory(neml2)
add_executable(foo main.cxx)
target_link_libraries(foo neml2)

The above snippet assumes NEML2 is checked out to the directory neml2, i.e., as a git submodule.

FetchContent

Alternatively, you may use CMake's FetchContent module to integrate NEML2 into your project:

FetchContent_Declare(
  neml2
  GIT_REPOSITORY https://github.com/applied-material-modeling/neml2.git
  GIT_TAG v2.1.0
)
FetchContent_MakeAvailable(neml2)
add_executable(foo main.cxx)
target_link_libraries(foo neml2)

find_package

NEML2 can also be discovered from its installation location relying on CMake's config mode find_package function

find_package(neml2 CONFIG)
add_executable(foo main.cxx)
target_link_libraries(foo neml2::neml2)

Note that the config mode search defines several imported targets under the neml2:: namespace. For example, neml2::misc corresponds to the misc library of NEML2, etc. The neml2::neml2 is an interface target that transitively links to all NEML2 libraries.