Add CMake build support for find_package(QUIP)

[jameskermode]

Summary

Adds CMake package config support so LAMMPS and other CMake projects can use QUIP libraries via find_package(QUIP).

Closes #711

Changes

• Add cmake/QUIPConfig.cmake.in template that creates imported targets:
  • QUIP::fox, QUIP::libAtoms, QUIP::GAP, QUIP::Potentials, QUIP::Utils
  • QUIP::QUIP (unified interface target)
• Use Meson's cmake module to generate QUIPConfig.cmake and QUIPConfigVersion.cmake during installation
• Add install: true to all library definitions so they are installed to the lib directory
• Update fox and GAP submodules to include install: true

Usage

After building and installing QUIP with Meson:

meson setup builddir -Dgap=true
meson compile -C builddir
meson install -C builddir

CMake projects can then use:

find_package(QUIP REQUIRED)
target_link_libraries(myapp QUIP::QUIP)

Submodule PRs

This PR depends on corresponding changes in the submodules:

• fox: https://github.com/libAtoms/fox/compare/cmake-install-support
• GAP: https://github.com/libAtoms/GAP/compare/cmake-install-support

Test plan

• meson setup succeeds with -Dgap=true
• meson install installs all libraries and CMake config files
• Test CMake project can find_package(QUIP) and access all variables/targets

🤖 Generated with Claude Code

[jameskermode]

Tested and this should work with the LAMMPS QUIP plugin.

LAMMPS's cmake/Modules/Packages/ML-QUIP.cmake needs modification to support Meson-built QUIP. The change is to use CONFIG mode first (for Meson-built QUIP) before falling back to MODULE mode (for legacy Make-built libquip.a):

enable_language(Fortran)
-find_package(QUIP QUIET)
+
+# Try to find QUIP - first via CMake config files (Meson-built QUIP),
+# then via legacy FindQUIP module (Make-built libquip.a)
+find_package(QUIP QUIET CONFIG)
+if(NOT QUIP_FOUND)
+  find_package(QUIP QUIET MODULE)
+endif()

 if(QUIP_FOUND)
...
 else()
-  find_package(QUIP REQUIRED)
+  # QUIP was already found at the top of this file, just link it
+  if(NOT QUIP_FOUND)
+    find_package(QUIP QUIET CONFIG)
+    if(NOT QUIP_FOUND)
+      find_package(QUIP REQUIRED MODULE)
+    endif()
+  endif()
   target_link_libraries(lammps PRIVATE QUIP::QUIP ${LAPACK_LIBRARIES})
 endif()

This change is backward compatible - it will still work with legacy Make-built QUIP if no CMake config files are found.

@bernstei if you would be willing to test this works for you too then we can think about whether/how to update LAMMPS.

[bernstei]

@bernstei if you would be willing to test this works for you too then we can think about whether/how to update LAMMPS.

do you mean just as a test on an independent setup? Because the only thing I ever do with cmake is compile lammps

[jameskermode]

Yes, just test the LAMMPS + QUIPS compilation with this branch independently. As you can see I got some AI coding assistance with the CMake/Meson bridge. I've run in manually myself but a second pair of eyes would be good.

[bernstei]

Yes, just test the LAMMPS + QUIPS compilation with this branch independently. As you can see I got some AI coding assistance with the CMake/Meson bridge. I've run in manually myself but a second pair of eyes would be good.

Sure, I'm happy to test that, but I'm a bit confused as to what exactly I should do.

Do I just grab a recent lammps, make this modification, and everything should work?

How does all this new stuff integrate with the auto download (or clone) and custom arch/Makefile.lammps that the lammps cmake currently creates? Do I need meson available?

[jameskermode]

This will only work with the no-download route for now, and yes you'd need Meson to compile QUIP. We'd need to make more changes in LAMMPS to make it integrate with CMake+Meson QUIP build with the auto download route.

Build and install QUIP with Meson:

  # Clone QUIP with submodules
  git clone --recursive https://github.com/libAtoms/QUIP.git
  cd QUIP

  # Checkout this PR branch
  git checkout cmake-support
  cd src/fox && git checkout cmake-install-support && cd ../..
  cd src/GAP && git checkout cmake-install-support && cd ../..

  # Build and install
  meson setup builddir -Dgap=true
  meson compile -C builddir
  meson install -C builddir --destdir=/tmp/quip-install

Build LAMMPS with the pre-built QUIP:

Apply the ML-QUIP.cmake patch above then:

  cd lammps/cmake
  cmake -B ../build \
    -DPKG_ML-QUIP=yes \
    -DDOWNLOAD_QUIP=no \
    -DCMAKE_PREFIX_PATH=/tmp/quip-install/usr/local
  cmake --build ../build

[bernstei]

I'm happy to test this procedure, assuming I can get meson to work

[bernstei]

Looks like it almost worked

[100%] Linking CXX executable lmp
/home/cluster/bernstei/.local/lib/python3.11/site-packages/cmake/data/bin/cmake -E cmake_link_script CMakeFiles/lmp.dir/link.txt --verbose=1
//home/Software/lammps/src/quip-install/usr/local/lib64/liblibAtoms.so: undefined reference to `f90wrap_abort_'
collect2: error: ld returned 1 exit status
/opt/ohpc/pub/compiler/gcc/12.4.0/bin/c++ -march=native -ffast-math -O3 -DNDEBUG CMakeFiles/lmp.dir/home/Software/lammps/src/lammps_cmake_symmetrix/src/main.cpp.o -o lmp  -Wl,-rpath,/home/Software/lammps/src/lammps_cmake_symmetrix/build_serial_cpu_test_QUIP_cmake:/home/Software/python/miniconda3/lib: liblammps.so.0 /opt/ohpc/pub/compiler/gcc/12.4.0/lib64/libgomp.so /lib64/libpthread.so -Wl,-rpath-link,/home/Software/python/miniconda3/lib:/home/Software/lammps/src/lammps_cmake_symmetrix/build_serial_cpu_test_QUIP_cmake
make[2]: *** [CMakeFiles/lmp.dir/build.make:103: lmp] Error 1
make[2]: Leaving directory '/home/cluster/Software/lammps/src/lammps_cmake_symmetrix/build_serial_cpu_test_QUIP_cmake'
make[1]: *** [CMakeFiles/Makefile2:670: CMakeFiles/lmp.dir/all] Error 2
make[1]: Leaving directory '/home/cluster/Software/lammps/src/lammps_cmake_symmetrix/build_serial_cpu_test_QUIP_cmake'
make: *** [Makefile:136: all] Error 2

[jameskermode]

Ah, I can see why that would happen. The f90wrap_abort_ function is in a separate stub library that's not being linked. On macOS I didn't see this because of -Wl,-undefined,dynamic_lookup, but Linux requires all symbols resolved at link time. Fix coming shortly.

[jameskermode]

That problem should be fixed now.

[bernstei]

Compiles with the cmake file patch above and the latest commit of this branch. I haven't checked performance.