source/unres/src_MD/md-diff/np/tnp_respa_i_step1.f

   1
   2 c-----------------------------------------------------------------
   3       subroutine tnp_respa_i_step1
   4 c Applying Nose-Poincare algorithm - step 1 to coordinates
   5 c J.Comput.Phys. 151 114 (1999) S.D.Bond B.J.Leimkuhler B.B.Laird
   6 c
   7 c d_t is not updated here, it is destroyed
   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 C_np,d_time_s,tmp,d_time_ss
  22
  23       d_time_s=d_time*0.5*s_np
  24 ct2      d_time_s=d_time*0.5*s12_np
  25
  26       do j=1,3
  27         d_t_new(j,0)=d_t_old(j,0)+d_a_old(j,0)*d_time_s
  28       enddo
  29       do i=nnt,nct-1
  30         do j=1,3
  31           d_t_new(j,i)=d_t_old(j,i)+d_a_old(j,i)*d_time_s
  32         enddo
  33       enddo
  34       do i=nnt,nct
  35         if (itype(i).ne.10) then
  36           inres=i+nres
  37           do j=1,3
  38            d_t_new(j,inres)=d_t_old(j,inres)+d_a_old(j,inres)*d_time_s
  39           enddo
  40         endif
  41       enddo
  42
  43       do i=0,2*nres
  44        do j=1,3
  45         d_t(j,i)=d_t_new(j,i)
  46        enddo
  47       enddo
  48
  49       call kinetic(EK)
  50       EK=EK/s_np**2
  51
  52       C_np=0.5*d_time*(dimen*Rb*t_bath*(1.0+log(s_np))-EK+potE-Csplit)
  53      &                     -pi_np
  54
  55       pistar=-2.0*C_np/(1.0+sqrt(1.0-C_np*d_time/Q_np))
  56       tmp=0.5*d_time*pistar/Q_np
  57       s12_np=s_np*(1.0+tmp)/(1.0-tmp)
  58
  59       d_time_ss=0.5*d_time*(1.0/s12_np+1.0/s_np)
  60 ct2      d_time_ss=d_time/s12_np
  61 c      d_time_ss=0.5*d_time*(1.0/sold_np+1.0/s_np)
  62
  63       do j=1,3
  64         dc(j,0)=dc_old(j,0)+d_t_new(j,0)*d_time_ss
  65       enddo
  66       do i=nnt,nct-1
  67         do j=1,3
  68           dc(j,i)=dc_old(j,i)+d_t_new(j,i)*d_time_ss
  69         enddo
  70       enddo
  71       do i=nnt,nct
  72         if (itype(i).ne.10) then
  73           inres=i+nres
  74           do j=1,3
  75            dc(j,inres)=dc_old(j,inres)+d_t_new(j,inres)*d_time_ss
  76           enddo
  77         endif
  78       enddo
  79
  80       return
  81       end