soft_sphere_pair_force

torch_sim.models.soft_sphere.soft_sphere_pair_force(dr, sigma=DEFAULT_SIGMA, epsilon=DEFAULT_EPSILON, alpha=DEFAULT_ALPHA)[source]

Computes the pairwise repulsive forces between soft spheres with finite range.

This function implements a soft-core repulsive interaction that smoothly goes to zero at the cutoff distance sigma. The force magnitude is controlled by epsilon and its stiffness by alpha.

Parameters:

  • dr (Tensor) – A tensor of shape [n, m] containing pairwise distances between particles, where n and m represent different particle indices.

  • sigma (Tensor) – Particle diameter defining the interaction cutoff distance. Can be either a float scalar or a tensor of shape [n, m] for particle-specific diameters.

  • epsilon (Tensor) – Energy scale of the interaction. Can be either a float scalar or a tensor of shape [n, m] for particle-specific interaction strengths.

  • alpha (Tensor) – Exponent controlling the stiffness of the repulsion. Higher values create a harder repulsion. Can be either a float scalar or a tensor of shape [n, m].

Returns:

Forces between particle pairs with shape [n, m]. Forces are zero

for distances greater than sigma.

Return type:

Tensor