source/unres/src_MD/md-diff/md/sddir_verlet2.f

   1 c---------------------------------------------------------------------
   2       subroutine sddir_verlet2
   3 c  Calculating the adjusted velocities for accelerations
   4       implicit real*8 (a-h,o-z)
   5       include 'DIMENSIONS'
   6       include 'COMMON.CONTROL'
   7       include 'COMMON.VAR'
   8       include 'COMMON.MD'
   9       include 'COMMON.LANGEVIN'
  10       include 'COMMON.CHAIN'
  11       include 'COMMON.DERIV'
  12       include 'COMMON.GEO'
  13       include 'COMMON.LOCAL'
  14       include 'COMMON.INTERACT'
  15       include 'COMMON.IOUNITS'
  16       include 'COMMON.NAMES'
  17       double precision stochforcvec(MAXRES6),d_as_work1(MAXRES6)
  18       double precision cos60 /0.5d0/, sin60 /0.86602540378443864676d0/
  19 c Revised 3/31/05 AL: correlation between random contributions to
  20 c position and velocity increments included.
  21 c The correlation coefficients are calculated at low-friction limit.
  22 c Also, friction forces are now not calculated with new velocities.
  23
  24 c      call friction_force
  25       call stochastic_force(stochforcvec)
  26 c
  27 c Compute the acceleration due to friction forces (d_af_work) and stochastic
  28 c forces (d_as_work)
  29 c
  30       do i=1,dimen
  31 c        d_af_work(i)=0.0d0
  32         d_as_work1(i)=0.0d0
  33         do j=1,dimen
  34 c          d_af_work(i)=d_af_work(i)+Ginv(i,j)*fric_work(j)
  35           d_as_work1(i)=d_as_work1(i)+Ginv(i,j)*stochforcvec(j)
  36         enddo
  37       enddo
  38 c
  39 c Update velocities
  40 c
  41       do j=1,3
  42         d_t(j,0)=d_t_new(j,0)+(0.5d0*(d_a(j,0)+d_af_work(j))
  43      &    +sin60*d_as_work(j)+cos60*d_as_work1(j))*d_time
  44       enddo
  45       ind=3
  46       do i=nnt,nct-1
  47         do j=1,3
  48           d_t(j,i)=d_t_new(j,i)+(0.5d0*(d_a(j,i)+d_af_work(ind+j))
  49      &     +sin60*d_as_work(ind+j)+cos60*d_as_work1(ind+j))*d_time
  50         enddo
  51         ind=ind+3
  52       enddo
  53       do i=nnt,nct
  54         if (itype(i).ne.10) then
  55           inres=i+nres
  56           do j=1,3
  57             d_t(j,inres)=d_t_new(j,inres)+(0.5d0*(d_a(j,inres)
  58      &       +d_af_work(ind+j))+sin60*d_as_work(ind+j)
  59      &       +cos60*d_as_work1(ind+j))*d_time
  60           enddo
  61           ind=ind+3
  62         endif
  63       enddo
  64       return
  65       end