Nix flake¶

The flake builds libyodaLib and the seams CLI with Meson. It does not build Python or Lua. There are no overlays.

nix build                  # ./result/bin/seams
nix run . -- read input/traj/exampleTraj.lammpstrj
nix develop                # inputsFrom seams, plus gdb, ccache, clang-tools
nix flake update           # refresh the nixpkgs pin
nix fmt

nix build runs Meson doCheck: the Catch2 suite plus the CLI smoke tests seams_read, seams_help, seams_version, seams_features.

Flake outputs¶

From flake.nix. Supported systems: x86_64-linux, aarch64-linux, x86_64-darwin, aarch64-darwin.

output	value
`packages.<system>.seams`	`nix/package.nix` derivation
`packages.<system>.default`	same as `seams`
`apps.<system>.default`	`${packages.default}/bin/seams`
`checks.<system>.seams`	the `seams` package
`checks.<system>.default`	same as `seams`
`devShells.<system>.default`	`inputsFrom` the package; extra packages `gdb`, `ccache`, `clang-tools`
`formatter.<system>`	`nixfmt`

The only flake input is nixpkgs (github:NixOS/nixpkgs/nixos-unstable).

What the package enables¶

From nix/package.nix (pname = "seams", version = "2.2.0"):

on	Eigen, BLAS, LAPACK, Catch2 3, Highway (`libhwy`)
OpenMP	`dependency('openmp')` probe; Clang also gets `llvmPackages.openmp`
Meson flags	`with_tests=true`, `with_cli=true`, `with_python=false`, `with_lua=false`, `with_mpi=false`, `with_openmp_offload=false`
`mesonAutoFeatures`	`disabled`
wrap mode	`nodownload` (Meson setup hook)

The fileset is meson.build, meson_options.txt, src, tests, input, templates, and the wraps readcon-core.wrap, vesin.wrap, robin-map.wrap, subprojects/packagefiles.

What stays off¶

`with_python`	Meson error if forced; Python is PydSEAMSlib
`with_lua`	Meson error if forced; Lua is yodaStruct
`with_mpi`	`false`
`with_openmp_offload`	`false`
vesin, readcon-core	wrap-git fallbacks are not fetched (`nodownload`)
chemfiles	not in the flake closure
IRA, sphericart, nauty	`auto_features=disabled`, so the `auto` probes stay off

seams --features on a flake build therefore reports Highway (and OpenMP when it linked) as enabled, and vesin, chemfiles, readcon-core, IRA/SOFI, sphericart, nauty, and MPI as disabled. Optional backends turn on only if a nixpkgs package is already in the closure.

Front-end flakes¶

yodaStruct and PydSEAMSlib have matching flakes. They take seams-core as a locked source input and build it as the Meson subproject.

Cachix¶

The dseams cache is optional (not a flake input):

nix-env -iA cachix -f https://cachix.org/api/v1/install
cachix use dseams