void realizeDynamics(const SBArticulatedBodyInertiaCache& abc,
const SBStateDigest& sbs) const {
// Mobilizer-specific.
const SBTreePositionCache& pc = sbs.getTreePositionCache();
const SBTreeVelocityCache& vc = sbs.getTreeVelocityCache();
SBDynamicsCache& dc = sbs.updDynamicsCache();
// Mobilizer independent.
calcJointIndependentDynamicsVel(pc,abc,vc,dc);
}
