computeGW method
Computes G*W, where W are the body velocities
Implementation
double computeGW() {
final ga = jacobianElementA;
final gb = jacobianElementB;
final bi = this.bi;
final bj = this.bj;
final vi = bi.velocity;
final vj = bj.velocity;
final wi = bi.angularVelocity;
final wj = bj.angularVelocity;
return ga.multiplyVectors(vi, wi) + gb.multiplyVectors(vj, wj);
}