xnn.common.models.dispersion.triplet_energy

xnn.common.models.dispersion.triplet_energy(a, b, c, j, k, edge_vec, r, z, c6_cj, c6_ck, c6_jk, r0_table, s9, alp3, cutoff, width, r0_prod=None)

ATM energy of one block of triplets, a third per center visit, (T,).

a, b index the two edges j -> c and k -> c of every triplet, c the shared center, j, k the outer atoms; c6_* are the three pair coefficients. The product of the three pair critical radii is read from r0_table by element, or taken from r0_prod when given. Shared by the scripted loop (three_body_energy()) and the recomputed one (three_body_energy_chunked()), so the formula lives once.

Parameters:

• a (Tensor)

• b (Tensor)

• c (Tensor)

• j (Tensor)

• k (Tensor)

• edge_vec (Tensor)

• r (Tensor)

• z (Tensor)

• c6_cj (Tensor)

• c6_ck (Tensor)

• c6_jk (Tensor)

• r0_table (Tensor)

• s9 (Tensor)

• alp3 (float)

• cutoff (float)

• width (float)

• r0_prod (Tensor | None)

Return type:

Tensor