pele.angleaxis.RigidFragment.distance_squared_grad

RigidFragment.distance_squared_grad(com1, p1, com2, p2)

calculate spring force between 2 sites

Parameters :

com1:

center of mass of 1st site

p1:

angle axis vector of 1st site

com2:

center of mass of 2nd site

p2:

angle axis vector of 2nd site

sitetype: AASiteType, optional

amgle axis site type with mass and moment of inertia tensor

returns: tuple

spring cart, spring rot