Read a molecular frame

Enable the readcon feature and call frame_from_con to obtain Cartesian positions, masses and an optional periodic cell. Parsing is provided by readcon-core.

An explicit lattice_vectors matrix in the frame metadata takes precedence. Otherwise the cell is reconstructed from all three lengths and all three angles. A zero length triplet denotes a nonperiodic frame. Partial or invalid periodic cells return an error.

The chemfiles feature enables the readcon-core format adapters. readcon-db supplies the corpus dependency for hosts that store traces and restarts. Surface implementations own their neighbour-list choice.

The triclinic metric and exact-lattice precedence are exercised by tests/io_cells.rs.

Build the optional native reader

The chemfiles feature builds a native dependency with CMake. For CMake 4, set the minimum policy version to 3.5 for that dependency:

CMAKE_POLICY_VERSION_MINIMUM=3.5 cargo build --locked --features chemfiles