initialize_momenta

torch_sim.integrators.md.initialize_momenta(positions, masses, system_idx, kT, generator=None)[source]

Initialize particle momenta based on temperature.

Generates random momenta for particles following the Maxwell-Boltzmann distribution at the specified temperature. The center of mass motion is removed to prevent system drift.

Parameters:

  • positions (torch.Tensor) – Particle positions [n_particles, n_dim]

  • masses (torch.Tensor) – Particle masses [n_particles]

  • system_idx (torch.Tensor) – System indices [n_particles]

  • kT (torch.Tensor) – Temperature in energy units [n_systems]

  • generator (Generator | None) – Optional torch.Generator for reproducibility.

Returns:

Initialized momenta [n_particles, n_dim]

Return type:

Tensor