source/unres/src_MD/md-diff/np/tnp1_step1.f

   1 c-------------------------------------------------------
   2
   3       subroutine tnp1_step1
   4 c Applying Nose-Poincare algorithm - step 1 to coordinates
   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_new(j,0)=d_t_old(j,0)+d_a_old(j,0)*d_time_s12
  31         dc(j,0)=dc_old(j,0)+d_t_new(j,0)*s12_dt
  32       enddo
  33       do i=nnt,nct-1
  34         do j=1,3
  35           d_t_new(j,i)=d_t_old(j,i)+d_a_old(j,i)*d_time_s12
  36           dc(j,i)=dc_old(j,i)+d_t_new(j,i)*s12_dt
  37         enddo
  38       enddo
  39       do i=nnt,nct
  40         if (itype(i).ne.10) then
  41           inres=i+nres
  42           do j=1,3
  43            d_t_new(j,inres)=d_t_old(j,inres)+d_a_old(j,inres)*d_time_s12
  44            dc(j,inres)=dc_old(j,inres)+d_t_new(j,inres)*s12_dt
  45           enddo
  46         endif
  47       enddo
  48       return
  49       end