source/unres/src_MD/md-diff/np/tnp1_respa_step1_.f

   1 c---------------------------------------------------------------------
   2 c-----------------------------------------------------------------
   3       subroutine tnp1_respa_step1_
   4 c Applying Nose-Poincare algorithm - step 1 to vel for RESPA
   5 c JPSJ 70 75 (2001) S. Nose
   6 c
   7 c d_t is not updated here
   8 c
   9       implicit real*8 (a-h,o-z)
  10       include 'DIMENSIONS'
  11       include 'COMMON.CONTROL'
  12       include 'COMMON.VAR'
  13       include 'COMMON.MD'
  14       include 'COMMON.CHAIN'
  15       include 'COMMON.DERIV'
  16       include 'COMMON.GEO'
  17       include 'COMMON.LOCAL'
  18       include 'COMMON.INTERACT'
  19       include 'COMMON.IOUNITS'
  20       include 'COMMON.NAMES'
  21       double precision adt,adt2,tmp
  22
  23       tmp=1+pi_np/(2*Q_np)*0.5*d_time
  24       s12_np=s_np*tmp**2
  25       pistar=pi_np/tmp
  26       s12_dt=d_time/s12_np
  27       d_time_s12=d_time*0.5*s12_np
  28
  29       do j=1,3
  30         d_t_old(j,0)=d_t_old(j,0)+d_a(j,0)*d_time_s12
  31       enddo
  32       do i=nnt,nct-1
  33         do j=1,3
  34           d_t_old(j,i)=d_t_old(j,i)+d_a(j,i)*d_time_s12
  35         enddo
  36       enddo
  37       do i=nnt,nct
  38         if (itype(i).ne.10) then
  39           inres=i+nres
  40           do j=1,3
  41            d_t_old(j,inres)=d_t_old(j,inres)+d_a(j,inres)*d_time_s12
  42           enddo
  43         endif
  44       enddo
  45       return
  46       end