c-----------------------------------------------------------------
      subroutine sddir_precalc
c Applying velocity Verlet algorithm - step 1 to coordinates        
      implicit real*8 (a-h,o-z)
      include 'DIMENSIONS'
#ifdef MPI
      include 'mpif.h'
#endif
      include 'COMMON.CONTROL'
      include 'COMMON.VAR'
      include 'COMMON.MD'
#ifndef LANG0
      include 'COMMON.LANGEVIN'
#else
      include 'COMMON.LANGEVIN.lang0'
#endif
      include 'COMMON.CHAIN'
      include 'COMMON.DERIV'
      include 'COMMON.GEO'
      include 'COMMON.LOCAL'
      include 'COMMON.INTERACT'
      include 'COMMON.IOUNITS'
      include 'COMMON.NAMES'
      include 'COMMON.TIME1'
      double precision stochforcvec(MAXRES6)
      common /stochcalc/ stochforcvec
c
c Compute friction and stochastic forces
c
      time00=MPI_Wtime()
      call friction_force
      time_fric=time_fric+MPI_Wtime()-time00
      time00=MPI_Wtime()
      call stochastic_force(stochforcvec) 
      time_stoch=time_stoch+MPI_Wtime()-time00
c
c Compute the acceleration due to friction forces (d_af_work) and stochastic
c forces (d_as_work)
c
      call ginv_mult(fric_work, d_af_work)
      call ginv_mult(stochforcvec, d_as_work)
      return
      end