source/unres/src_MD/src/md-diff/np/tnp1_respa_i_step1.f

   1 c-----------------------------------------------------------------
   2       subroutine tnp1_respa_i_step1
   3 c Applying Nose-Poincare algorithm - step 1 to coordinates
   4 c JPSJ 70 75 (2001) S. Nose
   5 c
   6 c d_t is not updated here
   7 c
   8       implicit real*8 (a-h,o-z)
   9       include 'DIMENSIONS'
  10       include 'COMMON.CONTROL'
  11       include 'COMMON.VAR'
  12       include 'COMMON.MD'
  13       include 'COMMON.CHAIN'
  14       include 'COMMON.DERIV'
  15       include 'COMMON.GEO'
  16       include 'COMMON.LOCAL'
  17       include 'COMMON.INTERACT'
  18       include 'COMMON.IOUNITS'
  19       include 'COMMON.NAMES'
  20       double precision adt,adt2,tmp
  21
  22       tmp=1+pi_np/(2*Q_np)*0.5*d_time
  23       s12_np=s_np*tmp**2
  24       pistar=pi_np/tmp
  25       s12_dt=d_time/s12_np
  26       d_time_s12=d_time*0.5*s12_np
  27
  28       do j=1,3
  29         d_t_new(j,0)=d_t_old(j,0)+d_a_old(j,0)*d_time_s12
  30         dc(j,0)=dc_old(j,0)+d_t_new(j,0)*s12_dt
  31       enddo
  32       do i=nnt,nct-1
  33         do j=1,3
  34           d_t_new(j,i)=d_t_old(j,i)+d_a_old(j,i)*d_time_s12
  35           dc(j,i)=dc_old(j,i)+d_t_new(j,i)*s12_dt
  36         enddo
  37       enddo
  38       do i=nnt,nct
  39         if (itype(i).ne.10) then
  40           inres=i+nres
  41           do j=1,3
  42            d_t_new(j,inres)=d_t_old(j,inres)+d_a_old(j,inres)*d_time_s12
  43            dc(j,inres)=dc_old(j,inres)+d_t_new(j,inres)*s12_dt
  44           enddo
  45         endif
  46       enddo
  47       return
  48       end