1 c---------------------------------------------------------------------
2 subroutine sddir_verlet1
3 c Applying velocity Verlet algorithm - step 1 to velocities
4 implicit real*8 (a-h,o-z)
6 include 'COMMON.CONTROL'
9 include 'COMMON.LANGEVIN'
10 include 'COMMON.CHAIN'
11 include 'COMMON.DERIV'
13 include 'COMMON.LOCAL'
14 include 'COMMON.INTERACT'
15 include 'COMMON.IOUNITS'
16 include 'COMMON.NAMES'
17 c Revised 3/31/05 AL: correlation between random contributions to
18 c position and velocity increments included.
19 double precision sqrt13 /0.57735026918962576451d0/ ! 1/sqrt(3)
20 double precision adt,adt2
22 c Add the contribution from BOTH friction and stochastic force to the
23 c coordinates, but ONLY the contribution from the friction forces to velocities
26 adt=(d_a_old(j,0)+d_af_work(j))*d_time
27 adt2=0.5d0*adt+sqrt13*d_as_work(j)*d_time
28 dc(j,0)=dc_old(j,0)+(d_t_old(j,0)+adt2)*d_time
29 d_t_new(j,0)=d_t_old(j,0)+0.5d0*adt
30 d_t(j,0)=d_t_old(j,0)+adt
35 adt=(d_a_old(j,i)+d_af_work(ind+j))*d_time
36 adt2=0.5d0*adt+sqrt13*d_as_work(ind+j)*d_time
37 dc(j,i)=dc_old(j,i)+(d_t_old(j,i)+adt2)*d_time
38 d_t_new(j,i)=d_t_old(j,i)+0.5d0*adt
39 d_t(j,i)=d_t_old(j,i)+adt
44 if (itype(i).ne.10) then
47 adt=(d_a_old(j,inres)+d_af_work(ind+j))*d_time
48 adt2=0.5d0*adt+sqrt13*d_as_work(ind+j)*d_time
49 dc(j,inres)=dc_old(j,inres)+(d_t_old(j,inres)+adt2)*d_time
50 d_t_new(j,inres)=d_t_old(j,inres)+0.5d0*adt
51 d_t(j,inres)=d_t_old(j,inres)+adt