def bond_e
import bend-prot@0.1.0.0/bonded.bend as Bondedimport Base
import bend-prot@0.1.0.0/geom.bend as G
import bend-prot@0.1.0.0/force.bend as F
62def bond_e(+pa: G.Vec3, +pb: G.Vec3, +k: F32, +r0: F32) -> F32:
63 (k * F.lj_sq((G.Vec3.dist(pa, pb) - r0 : F32)) : F32)