anchor.diff:            real*8, allocatable  :: rbTorque(:,:)
   c
             real*8, allocatable  :: rbDisp(:,:)
  +          real*8, allocatable  :: rbTotalDisp(:,:)
             real*8, allocatable  :: rbForceOld(:,:)
             real*8, allocatable  :: rbTorqueOld(:,:)
             real*8, allocatable  :: rbVelOld(:,:)
  
positive.code: c
  c----------------------------------------------------------------------
  c
  
  c
  c----------------------------------------------------------------------
  c
  
  c
  c----------------------------------------------------------------------
  c
  
  
negative.code:      &                    (0.5 + bt/am) * rbAccOld(j,1:3)
       &                  - bt * tmpAcc(1:3)    )
  c
  c.... get total displacement
  c
            rbTotalDisp(j,1:3) = rbTotalDisp(j,1:3) + rbDisp(j,1:3)
  c
  c.... get velocity
  c
            rbVelOld(j,1:3) = rbVelOld(j,1:3)
  