c---------------------------------------------------------------------
      subroutine predict_edrift(epdrift)
c
c Predict the drift of the potential energy
c
      implicit real*8 (a-h,o-z)
      include 'DIMENSIONS'
      include 'COMMON.CONTROL'
      include 'COMMON.VAR'
      include 'COMMON.MD'
      include 'COMMON.CHAIN'
      include 'COMMON.DERIV'
      include 'COMMON.GEO'
      include 'COMMON.LOCAL'
      include 'COMMON.INTERACT'
      include 'COMMON.IOUNITS'
      include 'COMMON.MUCA'
      double precision epdrift,epdriftij
c Drift of the potential energy
      epdrift=0.0d0
      do i=nnt,nct
c Backbone
        if (i.lt.nct) then
          do j=1,3
            epdriftij=dabs((d_a(j,i)-d_a_old(j,i))*gcart(j,i))
            if (lmuca) epdriftij=epdriftij*factor
c            write (iout,*) "back",i,j,epdriftij
            if (epdriftij.gt.epdrift) epdrift=epdriftij 
          enddo
        endif
c Side chains
        if (itype(i).ne.10) then
          do j=1,3 
            epdriftij=
     &       dabs((d_a(j,i+nres)-d_a_old(j,i+nres))*gxcart(j,i))
            if (lmuca) epdriftij=epdriftij*factor
c            write (iout,*) "side",i,j,epdriftij
            if (epdriftij.gt.epdrift) epdrift=epdriftij
          enddo
        endif
      enddo
      epdrift=0.5d0*epdrift*d_time*d_time
c      write (iout,*) "epdrift",epdrift
      return
      end