anchor.diff:  
      INTEGER(IntKi)                :: idx_qp         !< index counter for quadrature point
      INTEGER(IntKi)                :: temp_id2       !< Index to last node of previous element
  +   INTEGER(IntKi)                :: i,j            !< generic counters
      REAL(BDKi)                    :: tempR6(6,6)
  +   REAL(BDKi)                    :: tempBeta6(6,6)
  +
   
      ! see Bauchau 2011 Flexible Multibody Dynamics p 692-693, section 17.7.2
   
  
positive.code:          !!                      0  &  \left(\underline{\underline{R}} \underline{\underline{R}}_0\right)^T
           !!     \end{bmatrix} \f$
        m%qp%Stif(:,:,idx_qp,nelem) = MATMUL(tempR6,MATMUL(p%Stif0_QP(1:6,1:6,temp_id2+idx_qp),TRANSPOSE(tempR6)))
     ENDDO
  
  END SUBROUTINE BD_StifAtDeformedQP
  
negative.code: 
     INTEGER(IntKi)              :: idx_qp      !< index of current quadrature point
     
     
     IF (.NOT. fact) then ! skip all but Fc and Fd terms
     
  