QuantumMechanics relies on differentiable programming (for, e.g., calculating the Lagrangian of a phase of a space), which is implemented by Swift in an unstable module. Differentiation is delegated to such module because its implementation is far from trivial.
Only the latest major version of the toolchain can have its snapshot installed. To check which version is the latest major one, refer to the Releases page of Swift. ↩
-Some parts of the process of developing Deus are documented by the author himself in his video series Deus: Simulando o Universo (Deus: Simulating the Universe), in which the thinking behind the overall structure of the project is explained and important concepts regarding the physics themselves are taught.