56b3ea89b487f9e074a1044bab92074b2bbf405c
[unres.git] / MD_A-MTS.F
1       subroutine MD
2 c------------------------------------------------
3 c  The driver for molecular dynamics subroutines
4 c------------------------------------------------
5       implicit real*8 (a-h,o-z)
6       include 'DIMENSIONS'
7 #ifdef MPI
8       include "mpif.h"
9       integer IERROR,ERRCODE
10 #endif
11       include 'COMMON.SETUP'
12       include 'COMMON.CONTROL'
13       include 'COMMON.VAR'
14       include 'COMMON.MD'
15 #ifndef LANG0
16       include 'COMMON.LANGEVIN'
17 #else
18       include 'COMMON.LANGEVIN.lang0'
19 #endif
20       include 'COMMON.CHAIN'
21       include 'COMMON.DERIV'
22       include 'COMMON.GEO'
23       include 'COMMON.LOCAL'
24       include 'COMMON.INTERACT'
25       include 'COMMON.IOUNITS'
26       include 'COMMON.NAMES'
27       include 'COMMON.TIME1'
28       include 'COMMON.HAIRPIN'
29       double precision cm(3),L(3),vcm(3)
30 #ifdef VOUT
31       double precision v_work(maxres6),v_transf(maxres6)
32 #endif
33       integer ilen,rstcount
34       external ilen
35       character*50 tytul
36       common /gucio/ cm
37       integer itime
38       logical ovrtim
39 c
40 #ifdef MPI
41       if (ilen(tmpdir).gt.0)
42      &  call copy_to_tmp(pref_orig(:ilen(pref_orig))//"_"
43      &        //liczba(:ilen(liczba))//'.rst')
44 #else
45       if (ilen(tmpdir).gt.0)
46      &  call copy_to_tmp(pref_orig(:ilen(pref_orig))//"_"//'.rst')
47 #endif
48       t_MDsetup=0.0d0
49       t_langsetup=0.0d0
50       t_MD=0.0d0
51       t_enegrad=0.0d0
52       t_sdsetup=0.0d0
53       write (iout,'(20(1h=),a20,20(1h=))') "MD calculation started"
54 #ifdef MPI
55       tt0=MPI_Wtime()
56 #else
57       tt0 = tcpu()
58 #endif
59 c Determine the inverse of the inertia matrix.
60       call setup_MD_matrices
61 c Initialize MD
62       call init_MD
63 #ifdef MPI
64       t_MDsetup = MPI_Wtime()-tt0
65 #else
66       t_MDsetup = tcpu()-tt0
67 #endif
68       rstcount=0 
69 c   Entering the MD loop       
70 #ifdef MPI
71       tt0 = MPI_Wtime()
72 #else
73       tt0 = tcpu()
74 #endif
75       if (lang.eq.2 .or. lang.eq.3) then
76 #ifndef   LANG0
77         call setup_fricmat
78         if (lang.eq.2) then
79           call sd_verlet_p_setup        
80         else
81           call sd_verlet_ciccotti_setup
82         endif
83         do i=1,dimen
84           do j=1,dimen
85             pfric0_mat(i,j,0)=pfric_mat(i,j)
86             afric0_mat(i,j,0)=afric_mat(i,j)
87             vfric0_mat(i,j,0)=vfric_mat(i,j)
88             prand0_mat(i,j,0)=prand_mat(i,j)
89             vrand0_mat1(i,j,0)=vrand_mat1(i,j)
90             vrand0_mat2(i,j,0)=vrand_mat2(i,j)
91           enddo
92         enddo
93         flag_stoch(0)=.true.
94         do i=1,maxflag_stoch
95           flag_stoch(i)=.false.
96         enddo  
97 #else
98         write (iout,*) 
99      &   "LANG=2 or 3 NOT SUPPORTED. Recompile without -DLANG0"
100 #ifdef MPI
101         call MPI_Abort(MPI_COMM_WORLD,IERROR,ERRCODE)
102 #endif
103         stop
104 #endif
105       else if (lang.eq.1 .or. lang.eq.4) then
106         call setup_fricmat
107       endif
108 #ifdef MPI
109       t_langsetup=MPI_Wtime()-tt0
110       tt0=MPI_Wtime()
111 #else
112       t_langsetup=tcpu()-tt0
113       tt0=tcpu()
114 #endif
115       do itime=1,n_timestep
116         if (ovrtim()) exit
117         if (large.and. mod(itime,ntwe).eq.0) 
118      &    write (iout,*) "itime",itime
119         rstcount=rstcount+1
120         if (lang.gt.0 .and. surfarea .and. 
121      &      mod(itime,reset_fricmat).eq.0) then
122           if (lang.eq.2 .or. lang.eq.3) then
123 #ifndef LANG0
124             call setup_fricmat
125             if (lang.eq.2) then
126               call sd_verlet_p_setup
127             else
128               call sd_verlet_ciccotti_setup
129             endif
130             do i=1,dimen
131               do j=1,dimen
132                 pfric0_mat(i,j,0)=pfric_mat(i,j)
133                 afric0_mat(i,j,0)=afric_mat(i,j)
134                 vfric0_mat(i,j,0)=vfric_mat(i,j)
135                 prand0_mat(i,j,0)=prand_mat(i,j)
136                 vrand0_mat1(i,j,0)=vrand_mat1(i,j)
137                 vrand0_mat2(i,j,0)=vrand_mat2(i,j)
138               enddo
139             enddo
140             flag_stoch(0)=.true.
141             do i=1,maxflag_stoch
142               flag_stoch(i)=.false.
143             enddo   
144 #endif
145           else if (lang.eq.1 .or. lang.eq.4) then
146             call setup_fricmat
147           endif
148           write (iout,'(a,i10)') 
149      &      "Friction matrix reset based on surface area, itime",itime
150         endif
151         if (reset_vel .and. tbf .and. lang.eq.0 
152      &      .and. mod(itime,count_reset_vel).eq.0) then
153           call random_vel
154           write(iout,'(a,f20.2)') 
155      &     "Velocities reset to random values, time",totT       
156           do i=0,2*nres
157             do j=1,3
158               d_t_old(j,i)=d_t(j,i)
159             enddo
160           enddo
161         endif
162         if (reset_moment .and. mod(itime,count_reset_moment).eq.0) then
163           call inertia_tensor  
164           call vcm_vel(vcm)
165           do j=1,3
166              d_t(j,0)=d_t(j,0)-vcm(j)
167           enddo
168           call kinetic(EK)
169           kinetic_T=2.0d0/(dimen3*Rb)*EK
170           scalfac=dsqrt(T_bath/kinetic_T)
171           write(iout,'(a,f20.2)') "Momenta zeroed out, time",totT       
172           do i=0,2*nres
173             do j=1,3
174               d_t_old(j,i)=scalfac*d_t(j,i)
175             enddo
176           enddo
177         endif  
178         if (lang.ne.4) then
179           if (RESPA) then
180 c Time-reversible RESPA algorithm 
181 c (Tuckerman et al., J. Chem. Phys., 97, 1990, 1992)
182             call RESPA_step(itime)
183           else
184 c Variable time step algorithm.
185             call velverlet_step(itime)
186           endif
187         else
188 #ifdef BROWN
189           call brown_step(itime)
190 #else
191           print *,"Brown dynamics not here!"
192 #ifdef MPI
193           call MPI_Abort(MPI_COMM_WORLD,IERROR,ERRCODE)
194 #endif
195           stop
196 #endif
197         endif
198         if (ntwe.ne.0) then
199          if (mod(itime,ntwe).eq.0) call statout(itime)
200 #ifdef VOUT
201         do j=1,3
202           v_work(j)=d_t(j,0)
203         enddo
204         ind=3
205         do i=nnt,nct-1
206           do j=1,3
207             ind=ind+1
208             v_work(ind)=d_t(j,i)
209           enddo
210         enddo
211         do i=nnt,nct
212           if (itype(i).ne.10 .and. itype(i).ne.21) then
213             do j=1,3
214               ind=ind+1
215               v_work(ind)=d_t(j,i+nres)
216             enddo
217           endif
218         enddo
219
220         write (66,'(80f10.5)') 
221      &    ((d_t(j,i),j=1,3),i=0,nres-1),((d_t(j,i+nres),j=1,3),i=1,nres)
222         do i=1,ind
223           v_transf(i)=0.0d0
224           do j=1,ind
225             v_transf(i)=v_transf(i)+gvec(j,i)*v_work(j)
226           enddo
227            v_transf(i)= v_transf(i)*dsqrt(geigen(i))
228         enddo
229         write (67,'(80f10.5)') (v_transf(i),i=1,ind)
230 #endif
231         endif
232         if (mod(itime,ntwx).eq.0) then
233           write (tytul,'("time",f8.2)') totT
234           if(mdpdb) then
235              call hairpin(.true.,nharp,iharp)
236              call secondary2(.true.)
237              call pdbout(potE,tytul,ipdb)
238           else 
239              call cartout(totT)
240           endif
241         endif
242         if (rstcount.eq.1000.or.itime.eq.n_timestep) then
243            open(irest2,file=rest2name,status='unknown')
244            write(irest2,*) totT,EK,potE,totE,t_bath
245            do i=1,2*nres
246             write (irest2,'(3e15.5)') (d_t(j,i),j=1,3)
247            enddo
248            do i=1,2*nres
249             write (irest2,'(3e15.5)') (dc(j,i),j=1,3)
250            enddo
251           close(irest2)
252           rstcount=0
253         endif 
254       enddo
255 #ifdef MPI
256       t_MD=MPI_Wtime()-tt0
257 #else
258       t_MD=tcpu()-tt0
259 #endif
260       write (iout,'(//35(1h=),a10,35(1h=)/10(/a40,1pe15.5))') 
261      &  '  Timing  ',
262      & 'MD calculations setup:',t_MDsetup,
263      & 'Energy & gradient evaluation:',t_enegrad,
264      & 'Stochastic MD setup:',t_langsetup,
265      & 'Stochastic MD step setup:',t_sdsetup,
266      & 'MD steps:',t_MD
267       write (iout,'(/28(1h=),a25,27(1h=))') 
268      & '  End of MD calculation  '
269 #ifdef TIMING_ENE
270       write (iout,*) "time for etotal",t_etotal," elong",t_elong,
271      &  " eshort",t_eshort
272       write (iout,*) "time_fric",time_fric," time_stoch",time_stoch,
273      & " time_fricmatmult",time_fricmatmult," time_fsample ",
274      & time_fsample
275 #endif
276       return
277       end  
278 c-------------------------------------------------------------------------------
279       subroutine velverlet_step(itime)
280 c-------------------------------------------------------------------------------
281 c  Perform a single velocity Verlet step; the time step can be rescaled if 
282 c  increments in accelerations exceed the threshold
283 c-------------------------------------------------------------------------------
284       implicit real*8 (a-h,o-z)
285       include 'DIMENSIONS'
286 #ifdef MPI
287       include 'mpif.h'
288       integer ierror,ierrcode
289 #endif
290       include 'COMMON.SETUP'
291       include 'COMMON.CONTROL'
292       include 'COMMON.VAR'
293       include 'COMMON.MD'
294 #ifndef LANG0
295       include 'COMMON.LANGEVIN'
296 #else
297       include 'COMMON.LANGEVIN.lang0'
298 #endif
299       include 'COMMON.CHAIN'
300       include 'COMMON.DERIV'
301       include 'COMMON.GEO'
302       include 'COMMON.LOCAL'
303       include 'COMMON.INTERACT'
304       include 'COMMON.IOUNITS'
305       include 'COMMON.NAMES'
306       include 'COMMON.TIME1'
307       include 'COMMON.MUCA'
308       double precision vcm(3),incr(3)
309       double precision cm(3),L(3)
310       integer ilen,count,rstcount
311       external ilen
312       character*50 tytul
313       integer maxcount_scale /20/
314       common /gucio/ cm
315       double precision stochforcvec(MAXRES6)
316       common /stochcalc/ stochforcvec
317       integer itime
318       logical scale
319 c
320       scale=.true.
321       icount_scale=0
322       if (lang.eq.1) then
323         call sddir_precalc
324       else if (lang.eq.2 .or. lang.eq.3) then
325 #ifndef LANG0
326         call stochastic_force(stochforcvec)
327 #else
328         write (iout,*) 
329      &   "LANG=2 or 3 NOT SUPPORTED. Recompile without -DLANG0"
330 #ifdef MPI
331         call MPI_Abort(MPI_COMM_WORLD,IERROR,ERRCODE)
332 #endif
333         stop
334 #endif
335       endif
336       itime_scal=0
337       do while (scale)
338         icount_scale=icount_scale+1
339         if (icount_scale.gt.maxcount_scale) then
340           write (iout,*) 
341      &      "ERROR: too many attempts at scaling down the time step. ",
342      &      "amax=",amax,"epdrift=",epdrift,
343      &      "damax=",damax,"edriftmax=",edriftmax,
344      &      "d_time=",d_time
345           call flush(iout)
346 #ifdef MPI
347           call MPI_Abort(MPI_COMM_WORLD,IERROR,IERRCODE)
348 #endif
349           stop
350         endif
351 c First step of the velocity Verlet algorithm
352         if (lang.eq.2) then
353 #ifndef LANG0
354           call sd_verlet1
355 #endif
356         else if (lang.eq.3) then
357 #ifndef LANG0
358           call sd_verlet1_ciccotti
359 #endif
360         else if (lang.eq.1) then
361           call sddir_verlet1
362         else
363           call verlet1
364         endif     
365 c Build the chain from the newly calculated coordinates 
366         call chainbuild_cart
367         if (rattle) call rattle1
368         if (ntwe.ne.0) then
369         if (large.and. mod(itime,ntwe).eq.0) then
370           write (iout,*) "Cartesian and internal coordinates: step 1"
371           call cartprint
372           call intout
373           write (iout,*) "dC"
374           do i=0,nres
375             write (iout,'(i3,3f10.5,3x,3f10.5)') i,(dc(j,i),j=1,3),
376      &      (dc(j,i+nres),j=1,3)
377           enddo
378           write (iout,*) "Accelerations"
379           do i=0,nres
380             write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_a(j,i),j=1,3),
381      &      (d_a(j,i+nres),j=1,3)
382           enddo
383           write (iout,*) "Velocities, step 1"
384           do i=0,nres
385             write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_t(j,i),j=1,3),
386      &      (d_t(j,i+nres),j=1,3)
387           enddo
388         endif
389         endif
390 #ifdef MPI
391         tt0 = MPI_Wtime()
392 #else
393         tt0 = tcpu()
394 #endif
395 c Calculate energy and forces
396         call zerograd
397         call etotal(potEcomp)
398         if (large.and. mod(itime,ntwe).eq.0) 
399      &    call enerprint(potEcomp)
400 #ifdef TIMING_ENE
401 #ifdef MPI
402         t_etotal=t_etotal+MPI_Wtime()-tt0
403 #else
404         t_etotal=t_etotal+tcpu()-tt0
405 #endif
406 #endif
407         potE=potEcomp(0)-potEcomp(20)
408         call cartgrad
409 c Get the new accelerations
410         call lagrangian
411 #ifdef MPI
412         t_enegrad=t_enegrad+MPI_Wtime()-tt0
413 #else
414         t_enegrad=t_enegrad+tcpu()-tt0
415 #endif
416 c Determine maximum acceleration and scale down the timestep if needed
417         call max_accel
418         amax=amax/(itime_scal+1)**2
419         call predict_edrift(epdrift)
420         if (amax/(itime_scal+1).gt.damax .or. epdrift.gt.edriftmax) then
421 c Maximum acceleration or maximum predicted energy drift exceeded, rescale the time step
422           scale=.true.
423           ifac_time=dmax1(dlog(amax/damax),dlog(epdrift/edriftmax))
424      &      /dlog(2.0d0)+1
425           itime_scal=itime_scal+ifac_time
426 c          fac_time=dmin1(damax/amax,0.5d0)
427           fac_time=0.5d0**ifac_time
428           d_time=d_time*fac_time
429           if (lang.eq.2 .or. lang.eq.3) then 
430 #ifndef LANG0
431 c            write (iout,*) "Calling sd_verlet_setup: 1"
432 c Rescale the stochastic forces and recalculate or restore 
433 c the matrices of tinker integrator
434             if (itime_scal.gt.maxflag_stoch) then
435               if (large) write (iout,'(a,i5,a)') 
436      &         "Calculate matrices for stochastic step;",
437      &         " itime_scal ",itime_scal
438               if (lang.eq.2) then
439                 call sd_verlet_p_setup
440               else
441                 call sd_verlet_ciccotti_setup
442               endif
443               write (iout,'(2a,i3,a,i3,1h.)') 
444      &         "Warning: cannot store matrices for stochastic",
445      &         " integration because the index",itime_scal,
446      &         " is greater than",maxflag_stoch
447               write (iout,'(2a)')"Increase MAXFLAG_STOCH or use direct",
448      &         " integration Langevin algorithm for better efficiency."
449             else if (flag_stoch(itime_scal)) then
450               if (large) write (iout,'(a,i5,a,l1)') 
451      &         "Restore matrices for stochastic step; itime_scal ",
452      &         itime_scal," flag ",flag_stoch(itime_scal)
453               do i=1,dimen
454                 do j=1,dimen
455                   pfric_mat(i,j)=pfric0_mat(i,j,itime_scal)
456                   afric_mat(i,j)=afric0_mat(i,j,itime_scal)
457                   vfric_mat(i,j)=vfric0_mat(i,j,itime_scal)
458                   prand_mat(i,j)=prand0_mat(i,j,itime_scal)
459                   vrand_mat1(i,j)=vrand0_mat1(i,j,itime_scal)
460                   vrand_mat2(i,j)=vrand0_mat2(i,j,itime_scal)
461                 enddo
462               enddo
463             else
464               if (large) write (iout,'(2a,i5,a,l1)') 
465      &         "Calculate & store matrices for stochastic step;",
466      &         " itime_scal ",itime_scal," flag ",flag_stoch(itime_scal)
467               if (lang.eq.2) then
468                 call sd_verlet_p_setup  
469               else
470                 call sd_verlet_ciccotti_setup
471               endif
472               flag_stoch(ifac_time)=.true.
473               do i=1,dimen
474                 do j=1,dimen
475                   pfric0_mat(i,j,itime_scal)=pfric_mat(i,j)
476                   afric0_mat(i,j,itime_scal)=afric_mat(i,j)
477                   vfric0_mat(i,j,itime_scal)=vfric_mat(i,j)
478                   prand0_mat(i,j,itime_scal)=prand_mat(i,j)
479                   vrand0_mat1(i,j,itime_scal)=vrand_mat1(i,j)
480                   vrand0_mat2(i,j,itime_scal)=vrand_mat2(i,j)
481                 enddo
482               enddo
483             endif
484             fac_time=1.0d0/dsqrt(fac_time)
485             do i=1,dimen
486               stochforcvec(i)=fac_time*stochforcvec(i)
487             enddo
488 #endif
489           else if (lang.eq.1) then
490 c Rescale the accelerations due to stochastic forces
491             fac_time=1.0d0/dsqrt(fac_time)
492             do i=1,dimen
493               d_as_work(i)=d_as_work(i)*fac_time
494             enddo
495           endif
496           if (large) write (iout,'(a,i10,a,f8.6,a,i3,a,i3)')  
497      &      "itime",itime," Timestep scaled down to ",
498      &      d_time," ifac_time",ifac_time," itime_scal",itime_scal
499         else 
500 c Second step of the velocity Verlet algorithm
501           if (lang.eq.2) then   
502 #ifndef LANG0
503             call sd_verlet2
504 #endif
505           else if (lang.eq.3) then
506 #ifndef LANG0
507             call sd_verlet2_ciccotti
508 #endif
509           else if (lang.eq.1) then
510             call sddir_verlet2
511           else
512             call verlet2
513           endif                     
514           if (rattle) call rattle2
515           totT=totT+d_time
516           if (d_time.ne.d_time0) then
517             d_time=d_time0
518 #ifndef   LANG0
519             if (lang.eq.2 .or. lang.eq.3) then
520               if (large) write (iout,'(a)') 
521      &         "Restore original matrices for stochastic step"
522 c              write (iout,*) "Calling sd_verlet_setup: 2"
523 c Restore the matrices of tinker integrator if the time step has been restored
524               do i=1,dimen
525                 do j=1,dimen
526                   pfric_mat(i,j)=pfric0_mat(i,j,0)
527                   afric_mat(i,j)=afric0_mat(i,j,0)
528                   vfric_mat(i,j)=vfric0_mat(i,j,0)
529                   prand_mat(i,j)=prand0_mat(i,j,0)
530                   vrand_mat1(i,j)=vrand0_mat1(i,j,0)
531                   vrand_mat2(i,j)=vrand0_mat2(i,j,0)
532                 enddo
533               enddo
534             endif
535 #endif
536           endif
537           scale=.false.
538         endif
539       enddo
540 c Calculate the kinetic and the total energy and the kinetic temperature
541       call kinetic(EK)
542       totE=EK+potE
543 c diagnostics
544 c      call kinetic1(EK1)
545 c      write (iout,*) "step",itime," EK",EK," EK1",EK1
546 c end diagnostics
547 c Couple the system to Berendsen bath if needed
548       if (tbf .and. lang.eq.0) then
549         call verlet_bath
550       endif
551       kinetic_T=2.0d0/(dimen3*Rb)*EK
552 c Backup the coordinates, velocities, and accelerations
553       do i=0,2*nres
554         do j=1,3
555           dc_old(j,i)=dc(j,i)
556           d_t_old(j,i)=d_t(j,i)
557           d_a_old(j,i)=d_a(j,i)
558         enddo
559       enddo 
560       if (ntwe.ne.0) then
561       if (mod(itime,ntwe).eq.0 .and. large) then
562         write (iout,*) "Velocities, step 2"
563         do i=0,nres
564           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_t(j,i),j=1,3),
565      &      (d_t(j,i+nres),j=1,3)
566         enddo
567       endif
568       endif
569       return
570       end
571 c-------------------------------------------------------------------------------
572       subroutine RESPA_step(itime)
573 c-------------------------------------------------------------------------------
574 c  Perform a single RESPA step.
575 c-------------------------------------------------------------------------------
576       implicit real*8 (a-h,o-z)
577       include 'DIMENSIONS'
578 #ifdef MPI
579       include 'mpif.h'
580       integer IERROR,ERRCODE
581 #endif
582       include 'COMMON.SETUP'
583       include 'COMMON.CONTROL'
584       include 'COMMON.VAR'
585       include 'COMMON.MD'
586 #ifndef LANG0
587       include 'COMMON.LANGEVIN'
588 #else
589       include 'COMMON.LANGEVIN.lang0'
590 #endif
591       include 'COMMON.CHAIN'
592       include 'COMMON.DERIV'
593       include 'COMMON.GEO'
594       include 'COMMON.LOCAL'
595       include 'COMMON.INTERACT'
596       include 'COMMON.IOUNITS'
597       include 'COMMON.NAMES'
598       include 'COMMON.TIME1'
599       double precision energia_short(0:n_ene),
600      & energia_long(0:n_ene)
601       double precision cm(3),L(3),vcm(3),incr(3)
602       double precision dc_old0(3,0:maxres2),d_t_old0(3,0:maxres2),
603      & d_a_old0(3,0:maxres2)
604       logical PRINT_AMTS_MSG /.false./
605       integer ilen,count,rstcount
606       external ilen
607       character*50 tytul
608       integer maxcount_scale /10/
609       common /gucio/ cm
610       double precision stochforcvec(MAXRES6)
611       common /stochcalc/ stochforcvec
612       integer itime
613       logical scale
614       common /cipiszcze/ itt
615       itt=itime
616       if (ntwe.ne.0) then
617       if (large.and. mod(itime,ntwe).eq.0) then
618         write (iout,*) "***************** RESPA itime",itime
619         write (iout,*) "Cartesian and internal coordinates: step 0"
620 c        call cartprint
621         call pdbout(0.0d0,"cipiszcze",iout)
622         call intout
623         write (iout,*) "Accelerations from long-range forces"
624         do i=0,nres
625           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_a(j,i),j=1,3),
626      &      (d_a(j,i+nres),j=1,3)
627         enddo
628         write (iout,*) "Velocities, step 0"
629         do i=0,nres
630           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_t(j,i),j=1,3),
631      &      (d_t(j,i+nres),j=1,3)
632         enddo
633       endif
634       endif
635 c
636 c Perform the initial RESPA step (increment velocities)
637 c      write (iout,*) "*********************** RESPA ini"
638       call RESPA_vel
639       if (ntwe.ne.0) then
640       if (mod(itime,ntwe).eq.0 .and. large) then
641         write (iout,*) "Velocities, end"
642         do i=0,nres
643           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_t(j,i),j=1,3),
644      &      (d_t(j,i+nres),j=1,3)
645         enddo
646       endif
647       endif
648 c Compute the short-range forces
649 #ifdef MPI
650       tt0 =MPI_Wtime()
651 #else
652       tt0 = tcpu()
653 #endif
654 C 7/2/2009 commented out
655 c      call zerograd
656 c      call etotal_short(energia_short)
657 c      call cartgrad
658 c      call lagrangian
659 C 7/2/2009 Copy accelerations due to short-lange forces from previous MD step
660         do i=0,2*nres
661           do j=1,3
662             d_a(j,i)=d_a_short(j,i)
663           enddo
664         enddo
665       if (ntwe.ne.0) then
666       if (large.and. mod(itime,ntwe).eq.0) then
667         write (iout,*) "energia_short",energia_short(0)
668         write (iout,*) "Accelerations from short-range forces"
669         do i=0,nres
670           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_a(j,i),j=1,3),
671      &      (d_a(j,i+nres),j=1,3)
672         enddo
673       endif
674       endif
675 #ifdef MPI
676         t_enegrad=t_enegrad+MPI_Wtime()-tt0
677 #else
678         t_enegrad=t_enegrad+tcpu()-tt0
679 #endif
680       do i=0,2*nres
681         do j=1,3
682           dc_old(j,i)=dc(j,i)
683           d_t_old(j,i)=d_t(j,i)
684           d_a_old(j,i)=d_a(j,i)
685         enddo
686       enddo 
687 c 6/30/08 A-MTS: attempt at increasing the split number
688       do i=0,2*nres
689         do j=1,3
690           dc_old0(j,i)=dc_old(j,i)
691           d_t_old0(j,i)=d_t_old(j,i)
692           d_a_old0(j,i)=d_a_old(j,i)
693         enddo
694       enddo 
695       if (ntime_split.gt.ntime_split0) ntime_split=ntime_split/2
696       if (ntime_split.lt.ntime_split0) ntime_split=ntime_split0
697 c
698       scale=.true.
699       d_time0=d_time
700       do while (scale)
701
702       scale=.false.
703 c      write (iout,*) "itime",itime," ntime_split",ntime_split
704 c Split the time step
705       d_time=d_time0/ntime_split 
706 c Perform the short-range RESPA steps (velocity Verlet increments of
707 c positions and velocities using short-range forces)
708 c      write (iout,*) "*********************** RESPA split"
709       do itsplit=1,ntime_split
710         if (lang.eq.1) then
711           call sddir_precalc
712         else if (lang.eq.2 .or. lang.eq.3) then
713 #ifndef LANG0
714           call stochastic_force(stochforcvec)
715 #else
716           write (iout,*) 
717      &      "LANG=2 or 3 NOT SUPPORTED. Recompile without -DLANG0"
718 #ifdef MPI
719           call MPI_Abort(MPI_COMM_WORLD,IERROR,ERRCODE)
720 #endif
721           stop
722 #endif
723         endif
724 c First step of the velocity Verlet algorithm
725         if (lang.eq.2) then
726 #ifndef LANG0
727           call sd_verlet1
728 #endif
729         else if (lang.eq.3) then
730 #ifndef LANG0
731           call sd_verlet1_ciccotti
732 #endif
733         else if (lang.eq.1) then
734           call sddir_verlet1
735         else
736           call verlet1
737         endif
738 c Build the chain from the newly calculated coordinates 
739         call chainbuild_cart
740         if (rattle) call rattle1
741         if (ntwe.ne.0) then
742         if (large.and. mod(itime,ntwe).eq.0) then
743           write (iout,*) "***** ITSPLIT",itsplit
744           write (iout,*) "Cartesian and internal coordinates: step 1"
745           call pdbout(0.0d0,"cipiszcze",iout)
746 c          call cartprint
747           call intout
748           write (iout,*) "Velocities, step 1"
749           do i=0,nres
750             write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_t(j,i),j=1,3),
751      &        (d_t(j,i+nres),j=1,3)
752           enddo
753         endif
754         endif
755 #ifdef MPI
756         tt0 = MPI_Wtime()
757 #else
758         tt0 = tcpu()
759 #endif
760 c Calculate energy and forces
761         call zerograd
762         call etotal_short(energia_short)
763         if (large.and. mod(itime,ntwe).eq.0) 
764      &    call enerprint(energia_short)
765 #ifdef TIMING_ENE
766 #ifdef MPI
767         t_eshort=t_eshort+MPI_Wtime()-tt0
768 #else
769         t_eshort=t_eshort+tcpu()-tt0
770 #endif
771 #endif
772         call cartgrad
773 c Get the new accelerations
774         call lagrangian
775 C 7/2/2009 Copy accelerations due to short-lange forces to an auxiliary array
776         do i=0,2*nres
777           do j=1,3
778             d_a_short(j,i)=d_a(j,i)
779           enddo
780         enddo
781         if (ntwe.ne.0) then
782         if (large.and. mod(itime,ntwe).eq.0) then
783           write (iout,*)"energia_short",energia_short(0)
784           write (iout,*) "Accelerations from short-range forces"
785           do i=0,nres
786             write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_a(j,i),j=1,3),
787      &        (d_a(j,i+nres),j=1,3)
788           enddo
789         endif
790         endif
791 c 6/30/08 A-MTS
792 c Determine maximum acceleration and scale down the timestep if needed
793         call max_accel
794         amax=amax/ntime_split**2
795         call predict_edrift(epdrift)
796         if (ntwe.gt.0 .and. large .and. mod(itime,ntwe).eq.0) 
797      &   write (iout,*) "amax",amax," damax",damax,
798      &   " epdrift",epdrift," epdriftmax",epdriftmax
799 c Exit loop and try with increased split number if the change of
800 c acceleration is too big
801         if (amax.gt.damax .or. epdrift.gt.edriftmax) then
802           if (ntime_split.lt.maxtime_split) then
803             scale=.true.
804             ntime_split=ntime_split*2
805             do i=0,2*nres
806               do j=1,3
807                 dc_old(j,i)=dc_old0(j,i)
808                 d_t_old(j,i)=d_t_old0(j,i)
809                 d_a_old(j,i)=d_a_old0(j,i)
810               enddo
811             enddo 
812             if (PRINT_AMTS_MSG) then
813             write (iout,*) "acceleration/energy drift too large",amax,
814      &      epdrift," split increased to ",ntime_split," itime",itime,
815      &       " itsplit",itsplit
816             endif
817             exit
818           else
819             write (iout,*) 
820      &      "Uh-hu. Bumpy landscape. Maximum splitting number",
821      &       maxtime_split,
822      &      " already reached!!! Trying to carry on!"
823           endif
824         endif
825 #ifdef MPI
826         t_enegrad=t_enegrad+MPI_Wtime()-tt0
827 #else
828         t_enegrad=t_enegrad+tcpu()-tt0
829 #endif
830 c Second step of the velocity Verlet algorithm
831         if (lang.eq.2) then
832 #ifndef LANG0
833           call sd_verlet2
834 #endif
835         else if (lang.eq.3) then
836 #ifndef LANG0
837           call sd_verlet2_ciccotti
838 #endif
839         else if (lang.eq.1) then
840           call sddir_verlet2
841         else
842           call verlet2
843         endif
844         if (rattle) call rattle2
845 c Backup the coordinates, velocities, and accelerations
846         do i=0,2*nres
847           do j=1,3
848             dc_old(j,i)=dc(j,i)
849             d_t_old(j,i)=d_t(j,i)
850             d_a_old(j,i)=d_a(j,i)
851           enddo
852         enddo 
853       enddo
854
855       enddo ! while scale
856
857 c Restore the time step
858       d_time=d_time0
859 c Compute long-range forces
860 #ifdef MPI
861       tt0 =MPI_Wtime()
862 #else
863       tt0 = tcpu()
864 #endif
865       call zerograd
866       call etotal_long(energia_long)
867       if (large.and. mod(itime,ntwe).eq.0) 
868      &    call enerprint(energia_long)
869 #ifdef TIMING_ENE
870 #ifdef MPI
871         t_elong=t_elong+MPI_Wtime()-tt0
872 #else
873         t_elong=t_elong+tcpu()-tt0
874 #endif
875 #endif
876       call cartgrad
877       call lagrangian
878 #ifdef MPI
879         t_enegrad=t_enegrad+MPI_Wtime()-tt0
880 #else
881         t_enegrad=t_enegrad+tcpu()-tt0
882 #endif
883 c Compute accelerations from long-range forces
884       if (ntwe.ne.0) then
885       if (large.and. mod(itime,ntwe).eq.0) then
886         write (iout,*) "energia_long",energia_long(0)
887         write (iout,*) "Cartesian and internal coordinates: step 2"
888 c        call cartprint
889         call pdbout(0.0d0,"cipiszcze",iout)
890         call intout
891         write (iout,*) "Accelerations from long-range forces"
892         do i=0,nres
893           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_a(j,i),j=1,3),
894      &      (d_a(j,i+nres),j=1,3)
895         enddo
896         write (iout,*) "Velocities, step 2"
897         do i=0,nres
898           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_t(j,i),j=1,3),
899      &      (d_t(j,i+nres),j=1,3)
900         enddo
901       endif
902       endif
903 c Compute the final RESPA step (increment velocities)
904 c      write (iout,*) "*********************** RESPA fin"
905       call RESPA_vel
906 c Compute the complete potential energy
907       do i=0,n_ene
908         potEcomp(i)=energia_short(i)+energia_long(i)
909       enddo
910       potE=potEcomp(0)-potEcomp(20)
911 c      potE=energia_short(0)+energia_long(0)
912       totT=totT+d_time
913 c Calculate the kinetic and the total energy and the kinetic temperature
914       call kinetic(EK)
915       totE=EK+potE
916 c Couple the system to Berendsen bath if needed
917       if (tbf .and. lang.eq.0) then
918         call verlet_bath
919       endif
920       kinetic_T=2.0d0/(dimen3*Rb)*EK
921 c Backup the coordinates, velocities, and accelerations
922       if (ntwe.ne.0) then
923       if (mod(itime,ntwe).eq.0 .and. large) then
924         write (iout,*) "Velocities, end"
925         do i=0,nres
926           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_t(j,i),j=1,3),
927      &      (d_t(j,i+nres),j=1,3)
928         enddo
929       endif
930       endif
931       return
932       end
933 c---------------------------------------------------------------------
934       subroutine RESPA_vel
935 c  First and last RESPA step (incrementing velocities using long-range
936 c  forces).
937       implicit real*8 (a-h,o-z)
938       include 'DIMENSIONS'
939       include 'COMMON.CONTROL'
940       include 'COMMON.VAR'
941       include 'COMMON.MD'
942       include 'COMMON.CHAIN'
943       include 'COMMON.DERIV'
944       include 'COMMON.GEO'
945       include 'COMMON.LOCAL'
946       include 'COMMON.INTERACT'
947       include 'COMMON.IOUNITS'
948       include 'COMMON.NAMES'
949       do j=1,3
950         d_t(j,0)=d_t(j,0)+0.5d0*d_a(j,0)*d_time
951       enddo
952       do i=nnt,nct-1
953         do j=1,3
954           d_t(j,i)=d_t(j,i)+0.5d0*d_a(j,i)*d_time
955         enddo
956       enddo
957       do i=nnt,nct
958         if (itype(i).ne.10 .and. itype(i).ne.21) then
959           inres=i+nres
960           do j=1,3
961             d_t(j,inres)=d_t(j,inres)+0.5d0*d_a(j,inres)*d_time
962           enddo
963         endif
964       enddo 
965       return
966       end
967 c-----------------------------------------------------------------
968       subroutine verlet1
969 c Applying velocity Verlet algorithm - step 1 to coordinates
970       implicit real*8 (a-h,o-z)
971       include 'DIMENSIONS'
972       include 'COMMON.CONTROL'
973       include 'COMMON.VAR'
974       include 'COMMON.MD'
975       include 'COMMON.CHAIN'
976       include 'COMMON.DERIV'
977       include 'COMMON.GEO'
978       include 'COMMON.LOCAL'
979       include 'COMMON.INTERACT'
980       include 'COMMON.IOUNITS'
981       include 'COMMON.NAMES'
982       double precision adt,adt2
983         
984 #ifdef DEBUG
985       write (iout,*) "VELVERLET1 START: DC"
986       do i=0,nres
987         write (iout,'(i3,3f10.5,5x,3f10.5)') i,(dc(j,i),j=1,3),
988      &   (dc(j,i+nres),j=1,3)
989       enddo 
990 #endif
991       do j=1,3
992         adt=d_a_old(j,0)*d_time
993         adt2=0.5d0*adt
994         dc(j,0)=dc_old(j,0)+(d_t_old(j,0)+adt2)*d_time
995         d_t_new(j,0)=d_t_old(j,0)+adt2
996         d_t(j,0)=d_t_old(j,0)+adt
997       enddo
998       do i=nnt,nct-1    
999         do j=1,3    
1000           adt=d_a_old(j,i)*d_time
1001           adt2=0.5d0*adt
1002           dc(j,i)=dc_old(j,i)+(d_t_old(j,i)+adt2)*d_time
1003           d_t_new(j,i)=d_t_old(j,i)+adt2
1004           d_t(j,i)=d_t_old(j,i)+adt
1005         enddo
1006       enddo
1007       do i=nnt,nct
1008         if (itype(i).ne.10 .and. itype(i).ne.21) then
1009           inres=i+nres
1010           do j=1,3    
1011             adt=d_a_old(j,inres)*d_time
1012             adt2=0.5d0*adt
1013             dc(j,inres)=dc_old(j,inres)+(d_t_old(j,inres)+adt2)*d_time
1014             d_t_new(j,inres)=d_t_old(j,inres)+adt2
1015             d_t(j,inres)=d_t_old(j,inres)+adt
1016           enddo
1017         endif      
1018       enddo 
1019 #ifdef DEBUG
1020       write (iout,*) "VELVERLET1 END: DC"
1021       do i=0,nres
1022         write (iout,'(i3,3f10.5,5x,3f10.5)') i,(dc(j,i),j=1,3),
1023      &   (dc(j,i+nres),j=1,3)
1024       enddo 
1025 #endif
1026       return
1027       end
1028 c---------------------------------------------------------------------
1029       subroutine verlet2
1030 c  Step 2 of the velocity Verlet algorithm: update velocities
1031       implicit real*8 (a-h,o-z)
1032       include 'DIMENSIONS'
1033       include 'COMMON.CONTROL'
1034       include 'COMMON.VAR'
1035       include 'COMMON.MD'
1036       include 'COMMON.CHAIN'
1037       include 'COMMON.DERIV'
1038       include 'COMMON.GEO'
1039       include 'COMMON.LOCAL'
1040       include 'COMMON.INTERACT'
1041       include 'COMMON.IOUNITS'
1042       include 'COMMON.NAMES'
1043       do j=1,3
1044         d_t(j,0)=d_t_new(j,0)+0.5d0*d_a(j,0)*d_time
1045       enddo
1046       do i=nnt,nct-1
1047         do j=1,3
1048           d_t(j,i)=d_t_new(j,i)+0.5d0*d_a(j,i)*d_time
1049         enddo
1050       enddo
1051       do i=nnt,nct
1052         if (itype(i).ne.10 .and. itype(i).ne.21) then
1053           inres=i+nres
1054           do j=1,3
1055             d_t(j,inres)=d_t_new(j,inres)+0.5d0*d_a(j,inres)*d_time
1056           enddo
1057         endif
1058       enddo 
1059       return
1060       end
1061 c-----------------------------------------------------------------
1062       subroutine sddir_precalc
1063 c Applying velocity Verlet algorithm - step 1 to coordinates        
1064       implicit real*8 (a-h,o-z)
1065       include 'DIMENSIONS'
1066 #ifdef MPI
1067       include 'mpif.h'
1068 #endif
1069       include 'COMMON.CONTROL'
1070       include 'COMMON.VAR'
1071       include 'COMMON.MD'
1072 #ifndef LANG0
1073       include 'COMMON.LANGEVIN'
1074 #else
1075       include 'COMMON.LANGEVIN.lang0'
1076 #endif
1077       include 'COMMON.CHAIN'
1078       include 'COMMON.DERIV'
1079       include 'COMMON.GEO'
1080       include 'COMMON.LOCAL'
1081       include 'COMMON.INTERACT'
1082       include 'COMMON.IOUNITS'
1083       include 'COMMON.NAMES'
1084       include 'COMMON.TIME1'
1085       double precision stochforcvec(MAXRES6)
1086       common /stochcalc/ stochforcvec
1087 c
1088 c Compute friction and stochastic forces
1089 c
1090 #ifdef MPI
1091       time00=MPI_Wtime()
1092 #else
1093       time00=tcpu()
1094 #endif
1095       call friction_force
1096 #ifdef MPI
1097       time_fric=time_fric+MPI_Wtime()-time00
1098       time00=MPI_Wtime()
1099 #else
1100       time_fric=time_fric+tcpu()-time00
1101       time00=tcpu()
1102 #endif
1103       call stochastic_force(stochforcvec) 
1104 #ifdef MPI
1105       time_stoch=time_stoch+MPI_Wtime()-time00
1106 #else
1107       time_stoch=time_stoch+tcpu()-time00
1108 #endif
1109 c
1110 c Compute the acceleration due to friction forces (d_af_work) and stochastic
1111 c forces (d_as_work)
1112 c
1113       call ginv_mult(fric_work, d_af_work)
1114       call ginv_mult(stochforcvec, d_as_work)
1115       return
1116       end
1117 c---------------------------------------------------------------------
1118       subroutine sddir_verlet1
1119 c Applying velocity Verlet algorithm - step 1 to velocities        
1120       implicit real*8 (a-h,o-z)
1121       include 'DIMENSIONS'
1122       include 'COMMON.CONTROL'
1123       include 'COMMON.VAR'
1124       include 'COMMON.MD'
1125 #ifndef LANG0
1126       include 'COMMON.LANGEVIN'
1127 #else
1128       include 'COMMON.LANGEVIN.lang0'
1129 #endif
1130       include 'COMMON.CHAIN'
1131       include 'COMMON.DERIV'
1132       include 'COMMON.GEO'
1133       include 'COMMON.LOCAL'
1134       include 'COMMON.INTERACT'
1135       include 'COMMON.IOUNITS'
1136       include 'COMMON.NAMES'
1137 c Revised 3/31/05 AL: correlation between random contributions to 
1138 c position and velocity increments included.
1139       double precision sqrt13 /0.57735026918962576451d0/ ! 1/sqrt(3)
1140       double precision adt,adt2
1141 c
1142 c Add the contribution from BOTH friction and stochastic force to the
1143 c coordinates, but ONLY the contribution from the friction forces to velocities
1144 c
1145       do j=1,3
1146         adt=(d_a_old(j,0)+d_af_work(j))*d_time
1147         adt2=0.5d0*adt+sqrt13*d_as_work(j)*d_time
1148         dc(j,0)=dc_old(j,0)+(d_t_old(j,0)+adt2)*d_time
1149         d_t_new(j,0)=d_t_old(j,0)+0.5d0*adt
1150         d_t(j,0)=d_t_old(j,0)+adt
1151       enddo
1152       ind=3
1153       do i=nnt,nct-1    
1154         do j=1,3    
1155           adt=(d_a_old(j,i)+d_af_work(ind+j))*d_time
1156           adt2=0.5d0*adt+sqrt13*d_as_work(ind+j)*d_time
1157           dc(j,i)=dc_old(j,i)+(d_t_old(j,i)+adt2)*d_time
1158           d_t_new(j,i)=d_t_old(j,i)+0.5d0*adt
1159           d_t(j,i)=d_t_old(j,i)+adt
1160         enddo
1161         ind=ind+3
1162       enddo
1163       do i=nnt,nct
1164         if (itype(i).ne.10 .and. itype(i).ne.21) then
1165           inres=i+nres
1166           do j=1,3    
1167             adt=(d_a_old(j,inres)+d_af_work(ind+j))*d_time
1168             adt2=0.5d0*adt+sqrt13*d_as_work(ind+j)*d_time
1169             dc(j,inres)=dc_old(j,inres)+(d_t_old(j,inres)+adt2)*d_time
1170             d_t_new(j,inres)=d_t_old(j,inres)+0.5d0*adt
1171             d_t(j,inres)=d_t_old(j,inres)+adt
1172           enddo
1173           ind=ind+3
1174         endif      
1175       enddo 
1176       return
1177       end
1178 c---------------------------------------------------------------------
1179       subroutine sddir_verlet2
1180 c  Calculating the adjusted velocities for accelerations
1181       implicit real*8 (a-h,o-z)
1182       include 'DIMENSIONS'
1183       include 'COMMON.CONTROL'
1184       include 'COMMON.VAR'
1185       include 'COMMON.MD'
1186 #ifndef LANG0
1187       include 'COMMON.LANGEVIN'
1188 #else
1189       include 'COMMON.LANGEVIN.lang0'
1190 #endif
1191       include 'COMMON.CHAIN'
1192       include 'COMMON.DERIV'
1193       include 'COMMON.GEO'
1194       include 'COMMON.LOCAL'
1195       include 'COMMON.INTERACT'
1196       include 'COMMON.IOUNITS'
1197       include 'COMMON.NAMES'
1198       double precision stochforcvec(MAXRES6),d_as_work1(MAXRES6)
1199       double precision cos60 /0.5d0/, sin60 /0.86602540378443864676d0/
1200 c Revised 3/31/05 AL: correlation between random contributions to 
1201 c position and velocity increments included.
1202 c The correlation coefficients are calculated at low-friction limit.
1203 c Also, friction forces are now not calculated with new velocities.
1204
1205 c      call friction_force
1206       call stochastic_force(stochforcvec) 
1207 c
1208 c Compute the acceleration due to friction forces (d_af_work) and stochastic
1209 c forces (d_as_work)
1210 c
1211       call ginv_mult(stochforcvec, d_as_work1)
1212
1213 c
1214 c Update velocities
1215 c
1216       do j=1,3
1217         d_t(j,0)=d_t_new(j,0)+(0.5d0*(d_a(j,0)+d_af_work(j))
1218      &    +sin60*d_as_work(j)+cos60*d_as_work1(j))*d_time
1219       enddo
1220       ind=3
1221       do i=nnt,nct-1
1222         do j=1,3
1223           d_t(j,i)=d_t_new(j,i)+(0.5d0*(d_a(j,i)+d_af_work(ind+j))
1224      &     +sin60*d_as_work(ind+j)+cos60*d_as_work1(ind+j))*d_time
1225         enddo
1226         ind=ind+3
1227       enddo
1228       do i=nnt,nct
1229         if (itype(i).ne.10 .and. itype(i).ne.21) then
1230           inres=i+nres
1231           do j=1,3
1232             d_t(j,inres)=d_t_new(j,inres)+(0.5d0*(d_a(j,inres)
1233      &       +d_af_work(ind+j))+sin60*d_as_work(ind+j)
1234      &       +cos60*d_as_work1(ind+j))*d_time
1235           enddo
1236           ind=ind+3
1237         endif
1238       enddo 
1239       return
1240       end
1241 c---------------------------------------------------------------------
1242       subroutine max_accel
1243 c
1244 c Find the maximum difference in the accelerations of the the sites
1245 c at the beginning and the end of the time step.
1246 c
1247       implicit real*8 (a-h,o-z)
1248       include 'DIMENSIONS'
1249       include 'COMMON.CONTROL'
1250       include 'COMMON.VAR'
1251       include 'COMMON.MD'
1252       include 'COMMON.CHAIN'
1253       include 'COMMON.DERIV'
1254       include 'COMMON.GEO'
1255       include 'COMMON.LOCAL'
1256       include 'COMMON.INTERACT'
1257       include 'COMMON.IOUNITS'
1258       double precision aux(3),accel(3),accel_old(3),dacc
1259       do j=1,3
1260 c        aux(j)=d_a(j,0)-d_a_old(j,0)
1261          accel_old(j)=d_a_old(j,0)
1262          accel(j)=d_a(j,0)
1263       enddo 
1264       amax=0.0d0
1265       do i=nnt,nct
1266 c Backbone
1267         if (i.lt.nct) then
1268 c 7/3/08 changed to asymmetric difference
1269           do j=1,3
1270 c            accel(j)=aux(j)+0.5d0*(d_a(j,i)-d_a_old(j,i))
1271             accel_old(j)=accel_old(j)+0.5d0*d_a_old(j,i)
1272             accel(j)=accel(j)+0.5d0*d_a(j,i)
1273 c            if (dabs(accel(j)).gt.amax) amax=dabs(accel(j))
1274             if (dabs(accel(j)).gt.dabs(accel_old(j))) then
1275               dacc=dabs(accel(j)-accel_old(j))
1276               if (dacc.gt.amax) amax=dacc
1277             endif
1278           enddo
1279         endif
1280       enddo
1281 c Side chains
1282       do j=1,3
1283 c        accel(j)=aux(j)
1284         accel_old(j)=d_a_old(j,0)
1285         accel(j)=d_a(j,0)
1286       enddo
1287       if (nnt.eq.2) then
1288         do j=1,3
1289           accel_old(j)=accel_old(j)+d_a_old(j,1)
1290           accel(j)=accel(j)+d_a(j,1)
1291         enddo
1292       endif
1293       do i=nnt,nct
1294         if (itype(i).ne.10 .and. itype(i).ne.21) then
1295           do j=1,3 
1296 c            accel(j)=accel(j)+d_a(j,i+nres)-d_a_old(j,i+nres)
1297             accel_old(j)=accel_old(j)+d_a_old(j,i+nres)
1298             accel(j)=accel(j)+d_a(j,i+nres)
1299           enddo
1300         endif
1301         do j=1,3
1302 c          if (dabs(accel(j)).gt.amax) amax=dabs(accel(j))
1303           if (dabs(accel(j)).gt.dabs(accel_old(j))) then
1304             dacc=dabs(accel(j)-accel_old(j))
1305             if (dacc.gt.amax) amax=dacc
1306           endif
1307         enddo
1308         do j=1,3
1309           accel_old(j)=accel_old(j)+d_a_old(j,i)
1310           accel(j)=accel(j)+d_a(j,i)
1311 c          aux(j)=aux(j)+d_a(j,i)-d_a_old(j,i)
1312         enddo
1313       enddo
1314       return
1315       end       
1316 c---------------------------------------------------------------------
1317       subroutine predict_edrift(epdrift)
1318 c
1319 c Predict the drift of the potential energy
1320 c
1321       implicit real*8 (a-h,o-z)
1322       include 'DIMENSIONS'
1323       include 'COMMON.CONTROL'
1324       include 'COMMON.VAR'
1325       include 'COMMON.MD'
1326       include 'COMMON.CHAIN'
1327       include 'COMMON.DERIV'
1328       include 'COMMON.GEO'
1329       include 'COMMON.LOCAL'
1330       include 'COMMON.INTERACT'
1331       include 'COMMON.IOUNITS'
1332       include 'COMMON.MUCA'
1333       double precision epdrift,epdriftij
1334 c Drift of the potential energy
1335       epdrift=0.0d0
1336       do i=nnt,nct
1337 c Backbone
1338         if (i.lt.nct) then
1339           do j=1,3
1340             epdriftij=dabs((d_a(j,i)-d_a_old(j,i))*gcart(j,i))
1341             if (lmuca) epdriftij=epdriftij*factor
1342 c            write (iout,*) "back",i,j,epdriftij
1343             if (epdriftij.gt.epdrift) epdrift=epdriftij 
1344           enddo
1345         endif
1346 c Side chains
1347         if (itype(i).ne.10 .and. itype(i).ne.21) then
1348           do j=1,3 
1349             epdriftij=
1350      &       dabs((d_a(j,i+nres)-d_a_old(j,i+nres))*gxcart(j,i))
1351             if (lmuca) epdriftij=epdriftij*factor
1352 c            write (iout,*) "side",i,j,epdriftij
1353             if (epdriftij.gt.epdrift) epdrift=epdriftij
1354           enddo
1355         endif
1356       enddo
1357       epdrift=0.5d0*epdrift*d_time*d_time
1358 c      write (iout,*) "epdrift",epdrift
1359       return
1360       end       
1361 c-----------------------------------------------------------------------
1362       subroutine verlet_bath
1363 c
1364 c  Coupling to the thermostat by using the Berendsen algorithm
1365 c
1366       implicit real*8 (a-h,o-z)
1367       include 'DIMENSIONS'
1368       include 'COMMON.CONTROL'
1369       include 'COMMON.VAR'
1370       include 'COMMON.MD'
1371       include 'COMMON.CHAIN'
1372       include 'COMMON.DERIV'
1373       include 'COMMON.GEO'
1374       include 'COMMON.LOCAL'
1375       include 'COMMON.INTERACT'
1376       include 'COMMON.IOUNITS'
1377       include 'COMMON.NAMES'
1378       double precision T_half,fact
1379
1380       T_half=2.0d0/(dimen3*Rb)*EK
1381       fact=dsqrt(1.0d0+(d_time/tau_bath)*(t_bath/T_half-1.0d0))
1382 c      write(iout,*) "T_half", T_half
1383 c      write(iout,*) "EK", EK
1384 c      write(iout,*) "fact", fact                               
1385       do j=1,3
1386         d_t(j,0)=fact*d_t(j,0)
1387       enddo
1388       do i=nnt,nct-1
1389         do j=1,3
1390           d_t(j,i)=fact*d_t(j,i)
1391         enddo
1392       enddo
1393       do i=nnt,nct
1394         if (itype(i).ne.10 .and. itype(i).ne.21) then
1395           inres=i+nres
1396           do j=1,3
1397             d_t(j,inres)=fact*d_t(j,inres)
1398           enddo
1399         endif
1400       enddo 
1401       return
1402       end
1403 c---------------------------------------------------------
1404       subroutine init_MD
1405 c  Set up the initial conditions of a MD simulation
1406       implicit real*8 (a-h,o-z)
1407       include 'DIMENSIONS'
1408 #ifdef MP
1409       include 'mpif.h'
1410       character*16 form
1411       integer IERROR,ERRCODE
1412 #endif
1413       include 'COMMON.SETUP'
1414       include 'COMMON.CONTROL'
1415       include 'COMMON.VAR'
1416       include 'COMMON.MD'
1417 #ifndef LANG0
1418       include 'COMMON.LANGEVIN'
1419 #else
1420       include 'COMMON.LANGEVIN.lang0'
1421 #endif
1422       include 'COMMON.CHAIN'
1423       include 'COMMON.DERIV'
1424       include 'COMMON.GEO'
1425       include 'COMMON.LOCAL'
1426       include 'COMMON.INTERACT'
1427       include 'COMMON.IOUNITS'
1428       include 'COMMON.NAMES'
1429       include 'COMMON.REMD'
1430       real*8 energia_long(0:n_ene),
1431      &  energia_short(0:n_ene),vcm(3),incr(3)
1432       double precision cm(3),L(3),xv,sigv,lowb,highb
1433       double precision varia(maxvar)
1434       character*256 qstr
1435       integer ilen
1436       external ilen
1437       character*50 tytul
1438       logical file_exist
1439       common /gucio/ cm
1440       d_time0=d_time
1441 c      write(iout,*) "d_time", d_time
1442 c Compute the standard deviations of stochastic forces for Langevin dynamics
1443 c if the friction coefficients do not depend on surface area
1444       if (lang.gt.0 .and. .not.surfarea) then
1445         do i=nnt,nct-1
1446           stdforcp(i)=stdfp*dsqrt(gamp)
1447         enddo
1448         do i=nnt,nct
1449           stdforcsc(i)=stdfsc(itype(i))*dsqrt(gamsc(itype(i)))
1450         enddo
1451       endif
1452 c Open the pdb file for snapshotshots
1453 #ifdef MPI
1454       if(mdpdb) then
1455         if (ilen(tmpdir).gt.0) 
1456      &    call copy_to_tmp(pref_orig(:ilen(pref_orig))//"_MD"//
1457      &      liczba(:ilen(liczba))//".pdb")
1458         open(ipdb,
1459      &  file=prefix(:ilen(prefix))//"_MD"//liczba(:ilen(liczba))
1460      &  //".pdb")
1461       else
1462 #ifdef NOXDR
1463         if (ilen(tmpdir).gt.0 .and. (me.eq.king .or. .not.traj1file)) 
1464      &    call copy_to_tmp(pref_orig(:ilen(pref_orig))//"_MD"//
1465      &      liczba(:ilen(liczba))//".x")
1466         cartname=prefix(:ilen(prefix))//"_MD"//liczba(:ilen(liczba))
1467      &  //".x"
1468 #else
1469         if (ilen(tmpdir).gt.0 .and. (me.eq.king .or. .not.traj1file)) 
1470      &    call copy_to_tmp(pref_orig(:ilen(pref_orig))//"_MD"//
1471      &      liczba(:ilen(liczba))//".cx")
1472         cartname=prefix(:ilen(prefix))//"_MD"//liczba(:ilen(liczba))
1473      &  //".cx"
1474 #endif
1475       endif
1476 #else
1477       if(mdpdb) then
1478          if (ilen(tmpdir).gt.0) 
1479      &     call copy_to_tmp(pref_orig(:ilen(pref_orig))//"_MD.pdb")
1480          open(ipdb,file=prefix(:ilen(prefix))//"_MD.pdb")
1481       else
1482          if (ilen(tmpdir).gt.0) 
1483      &     call copy_to_tmp(pref_orig(:ilen(pref_orig))//"_MD.cx")
1484          cartname=prefix(:ilen(prefix))//"_MD.cx"
1485       endif
1486 #endif
1487       if (usampl) then
1488         write (qstr,'(256(1h ))')
1489         ipos=1
1490         do i=1,nfrag
1491           iq = qinfrag(i,iset)*10
1492           iw = wfrag(i,iset)/100
1493           if (iw.gt.0) then
1494             if(me.eq.king.or..not.out1file)
1495      &       write (iout,*) "Frag",qinfrag(i,iset),wfrag(i,iset),iq,iw
1496             write (qstr(ipos:ipos+6),'(2h_f,i1,1h_,i1,1h_,i1)') i,iq,iw
1497             ipos=ipos+7
1498           endif
1499         enddo
1500         do i=1,npair
1501           iq = qinpair(i,iset)*10
1502           iw = wpair(i,iset)/100
1503           if (iw.gt.0) then
1504             if(me.eq.king.or..not.out1file)
1505      &       write (iout,*) "Pair",i,qinpair(i,iset),wpair(i,iset),iq,iw
1506             write (qstr(ipos:ipos+6),'(2h_p,i1,1h_,i1,1h_,i1)') i,iq,iw
1507             ipos=ipos+7
1508           endif
1509         enddo
1510 c        pdbname=pdbname(:ilen(pdbname)-4)//qstr(:ipos-1)//'.pdb'
1511 #ifdef NOXDR
1512 c        cartname=cartname(:ilen(cartname)-2)//qstr(:ipos-1)//'.x'
1513 #else
1514 c        cartname=cartname(:ilen(cartname)-3)//qstr(:ipos-1)//'.cx'
1515 #endif
1516 c        statname=statname(:ilen(statname)-5)//qstr(:ipos-1)//'.stat'
1517       endif
1518       icg=1
1519       if (rest) then
1520        if (restart1file) then
1521          if (me.eq.king)
1522      &     inquire(file=mremd_rst_name,exist=file_exist)
1523 #ifdef MPI
1524            write (*,*) me," Before broadcast: file_exist",file_exist
1525          call MPI_Bcast(file_exist,1,MPI_LOGICAL,king,CG_COMM,
1526      &          IERR)
1527          write (*,*) me," After broadcast: file_exist",file_exist
1528 c        inquire(file=mremd_rst_name,exist=file_exist)
1529 #endif
1530         if(me.eq.king.or..not.out1file)
1531      &   write(iout,*) "Initial state read by master and distributed"
1532        else
1533          if (ilen(tmpdir).gt.0)
1534      &     call copy_to_tmp(pref_orig(:ilen(pref_orig))//'_'
1535      &      //liczba(:ilen(liczba))//'.rst')
1536         inquire(file=rest2name,exist=file_exist)
1537        endif
1538        if(file_exist) then
1539          if(.not.restart1file) then
1540            if(me.eq.king.or..not.out1file)
1541      &      write(iout,*) "Initial state will be read from file ",
1542      &      rest2name(:ilen(rest2name))
1543            call readrst
1544          endif  
1545          call rescale_weights(t_bath)
1546        else
1547         if(me.eq.king.or..not.out1file)then
1548          if (restart1file) then
1549           write(iout,*) "File ",mremd_rst_name(:ilen(mremd_rst_name)),
1550      &       " does not exist"
1551          else
1552           write(iout,*) "File ",rest2name(:ilen(rest2name)),
1553      &       " does not exist"
1554          endif
1555          write(iout,*) "Initial velocities randomly generated"
1556         endif
1557         call random_vel
1558         totT=0.0d0
1559        endif
1560       else
1561 c Generate initial velocities
1562         if(me.eq.king.or..not.out1file)
1563      &   write(iout,*) "Initial velocities randomly generated"
1564         call random_vel
1565         totT=0.0d0
1566       endif
1567 c      rest2name = prefix(:ilen(prefix))//'.rst'
1568       if(me.eq.king.or..not.out1file)then
1569        write (iout,*) "Initial velocities"
1570        do i=0,nres
1571          write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_t(j,i),j=1,3),
1572      &   (d_t(j,i+nres),j=1,3)
1573        enddo
1574 c  Zeroing the total angular momentum of the system
1575        write(iout,*) "Calling the zero-angular 
1576      & momentum subroutine"
1577       endif
1578       call inertia_tensor  
1579 c  Getting the potential energy and forces and velocities and accelerations
1580       call vcm_vel(vcm)
1581 c      write (iout,*) "velocity of the center of the mass:"
1582 c      write (iout,*) (vcm(j),j=1,3)
1583       do j=1,3
1584         d_t(j,0)=d_t(j,0)-vcm(j)
1585       enddo
1586 c Removing the velocity of the center of mass
1587       call vcm_vel(vcm)
1588       if(me.eq.king.or..not.out1file)then
1589        write (iout,*) "vcm right after adjustment:"
1590        write (iout,*) (vcm(j),j=1,3) 
1591       endif
1592       if (.not.rest) then               
1593          call chainbuild
1594          if(iranconf.ne.0) then
1595           if (overlapsc) then 
1596            print *, 'Calling OVERLAP_SC'
1597            call overlap_sc(fail)
1598           endif 
1599
1600           if (searchsc) then 
1601            call sc_move(2,nres-1,10,1d10,nft_sc,etot)
1602            print *,'SC_move',nft_sc,etot
1603            if(me.eq.king.or..not.out1file)
1604      &      write(iout,*) 'SC_move',nft_sc,etot
1605           endif 
1606
1607           if(dccart)then
1608            print *, 'Calling MINIM_DC'
1609            call minim_dc(etot,iretcode,nfun)
1610           else
1611            call geom_to_var(nvar,varia)
1612            print *,'Calling MINIMIZE.'
1613            call minimize(etot,varia,iretcode,nfun)
1614            call var_to_geom(nvar,varia)
1615           endif
1616           if(me.eq.king.or..not.out1file)
1617      &       write(iout,*) 'SUMSL return code is',iretcode,' eval ',nfun
1618          endif
1619       endif       
1620       call chainbuild_cart
1621       call kinetic(EK)
1622       if (tbf) then
1623         call verlet_bath
1624       endif       
1625       kinetic_T=2.0d0/(dimen3*Rb)*EK
1626       if(me.eq.king.or..not.out1file)then
1627        call cartprint
1628        call intout
1629       endif
1630 #ifdef MPI
1631       tt0=MPI_Wtime()
1632 #else
1633       tt0=tcpu()
1634 #endif
1635       call zerograd
1636       call etotal(potEcomp)
1637       if (large) call enerprint(potEcomp)
1638 #ifdef TIMING_ENE
1639 #ifdef MPI
1640       t_etotal=t_etotal+MPI_Wtime()-tt0
1641 #else
1642       t_etotal=t_etotal+tcpu()-tt0
1643 #endif
1644 #endif
1645       potE=potEcomp(0)
1646       call cartgrad
1647       call lagrangian
1648       call max_accel
1649       if (amax*d_time .gt. dvmax) then
1650         d_time=d_time*dvmax/amax
1651         if(me.eq.king.or..not.out1file) write (iout,*) 
1652      &   "Time step reduced to",d_time,
1653      &   " because of too large initial acceleration."
1654       endif
1655       if(me.eq.king.or..not.out1file)then 
1656        write(iout,*) "Potential energy and its components"
1657        call enerprint(potEcomp)
1658 c       write(iout,*) (potEcomp(i),i=0,n_ene)
1659       endif
1660       potE=potEcomp(0)-potEcomp(20)
1661       totE=EK+potE
1662       itime=0
1663       if (ntwe.ne.0) call statout(itime)
1664       if(me.eq.king.or..not.out1file)
1665      &  write (iout,'(/a/3(a25,1pe14.5/))') "Initial:",
1666      &   " Kinetic energy",EK," Potential energy",potE, 
1667      &   " Total energy",totE," Maximum acceleration ",
1668      &   amax
1669       if (large) then
1670         write (iout,*) "Initial coordinates"
1671         do i=1,nres
1672           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(c(j,i),j=1,3),
1673      &    (c(j,i+nres),j=1,3)
1674         enddo
1675         write (iout,*) "Initial dC"
1676         do i=0,nres
1677           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(dc(j,i),j=1,3),
1678      &    (dc(j,i+nres),j=1,3)
1679         enddo
1680         write (iout,*) "Initial velocities"
1681         write (iout,"(13x,' backbone ',23x,' side chain')")
1682         do i=0,nres
1683           write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_t(j,i),j=1,3),
1684      &    (d_t(j,i+nres),j=1,3)
1685         enddo
1686         write (iout,*) "Initial accelerations"
1687         do i=0,nres
1688 c          write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_a(j,i),j=1,3),
1689           write (iout,'(i3,3f15.10,3x,3f15.10)') i,(d_a(j,i),j=1,3),
1690      &    (d_a(j,i+nres),j=1,3)
1691         enddo
1692       endif
1693       do i=0,2*nres
1694         do j=1,3
1695           dc_old(j,i)=dc(j,i)
1696           d_t_old(j,i)=d_t(j,i)
1697           d_a_old(j,i)=d_a(j,i)
1698         enddo
1699 c        write (iout,*) "dc_old",i,(dc_old(j,i),j=1,3)
1700       enddo 
1701       if (RESPA) then
1702 #ifdef MPI
1703         tt0 =MPI_Wtime()
1704 #else
1705         tt0 = tcpu()
1706 #endif
1707         call zerograd
1708         call etotal_short(energia_short)
1709         if (large) call enerprint(potEcomp)
1710 #ifdef TIMING_ENE
1711 #ifdef MPI
1712         t_eshort=t_eshort+MPI_Wtime()-tt0
1713 #else
1714         t_eshort=t_eshort+tcpu()-tt0
1715 #endif
1716 #endif
1717         call cartgrad
1718         call lagrangian
1719         if(.not.out1file .and. large) then
1720           write (iout,*) "energia_long",energia_long(0),
1721      &     " energia_short",energia_short(0),
1722      &     " total",energia_long(0)+energia_short(0)
1723           write (iout,*) "Initial fast-force accelerations"
1724           do i=0,nres
1725             write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_a(j,i),j=1,3),
1726      &      (d_a(j,i+nres),j=1,3)
1727           enddo
1728         endif
1729 C 7/2/2009 Copy accelerations due to short-lange forces to an auxiliary array
1730         do i=0,2*nres
1731           do j=1,3
1732             d_a_short(j,i)=d_a(j,i)
1733           enddo
1734         enddo
1735 #ifdef MPI
1736         tt0=MPI_Wtime()
1737 #else
1738         tt0=tcpu()
1739 #endif
1740         call zerograd
1741         call etotal_long(energia_long)
1742         if (large) call enerprint(potEcomp)
1743 #ifdef TIMING_ENE
1744 #ifdef MPI
1745         t_elong=t_elong+MPI_Wtime()-tt0
1746 #else
1747         t_elong=t_elong+tcpu()-tt0
1748 #endif
1749 #endif
1750         call cartgrad
1751         call lagrangian
1752         if(.not.out1file .and. large) then
1753           write (iout,*) "energia_long",energia_long(0)
1754           write (iout,*) "Initial slow-force accelerations"
1755           do i=0,nres
1756             write (iout,'(i3,3f10.5,3x,3f10.5)') i,(d_a(j,i),j=1,3),
1757      &      (d_a(j,i+nres),j=1,3)
1758           enddo
1759         endif
1760 #ifdef MPI
1761         t_enegrad=t_enegrad+MPI_Wtime()-tt0
1762 #else
1763         t_enegrad=t_enegrad+tcpu()-tt0
1764 #endif
1765       endif
1766       return
1767       end
1768 c-----------------------------------------------------------
1769       subroutine random_vel
1770       implicit real*8 (a-h,o-z)
1771       include 'DIMENSIONS'
1772       include 'COMMON.CONTROL'
1773       include 'COMMON.VAR'
1774       include 'COMMON.MD'
1775 #ifndef LANG0
1776       include 'COMMON.LANGEVIN'
1777 #else
1778       include 'COMMON.LANGEVIN.lang0'
1779 #endif
1780       include 'COMMON.CHAIN'
1781       include 'COMMON.DERIV'
1782       include 'COMMON.GEO'
1783       include 'COMMON.LOCAL'
1784       include 'COMMON.INTERACT'
1785       include 'COMMON.IOUNITS'
1786       include 'COMMON.NAMES'
1787       include 'COMMON.TIME1'
1788       double precision xv,sigv,lowb,highb
1789 c Generate random velocities from Gaussian distribution of mean 0 and std of KT/m 
1790 c First generate velocities in the eigenspace of the G matrix
1791 c      write (iout,*) "Calling random_vel dimen dimen3",dimen,dimen3
1792 c      call flush(iout)
1793       xv=0.0d0
1794       ii=0
1795       do i=1,dimen
1796         do k=1,3
1797           ii=ii+1
1798           sigv=dsqrt((Rb*t_bath)/geigen(i))
1799           lowb=-5*sigv
1800           highb=5*sigv
1801           d_t_work_new(ii)=anorm_distr(xv,sigv,lowb,highb)
1802 c          write (iout,*) "i",i," ii",ii," geigen",geigen(i),
1803 c     &      " d_t_work_new",d_t_work_new(ii)
1804         enddo
1805       enddo
1806 c diagnostics
1807 c      Ek1=0.0d0
1808 c      ii=0
1809 c      do i=1,dimen
1810 c        do k=1,3
1811 c          ii=ii+1
1812 c          Ek1=Ek1+0.5d0*geigen(i)*d_t_work_new(ii)**2
1813 c        enddo
1814 c      enddo
1815 c      write (iout,*) "Ek from eigenvectors",Ek1
1816 c end diagnostics
1817 c Transform velocities to UNRES coordinate space
1818       do k=0,2       
1819         do i=1,dimen
1820           ind=(i-1)*3+k+1
1821           d_t_work(ind)=0.0d0
1822           do j=1,dimen
1823             d_t_work(ind)=d_t_work(ind)
1824      &                      +Gvec(i,j)*d_t_work_new((j-1)*3+k+1)
1825           enddo
1826 c          write (iout,*) "i",i," ind",ind," d_t_work",d_t_work(ind)
1827 c          call flush(iout)
1828         enddo
1829       enddo
1830 c Transfer to the d_t vector
1831       do j=1,3
1832         d_t(j,0)=d_t_work(j)
1833       enddo 
1834       ind=3
1835       do i=nnt,nct-1
1836         do j=1,3 
1837           ind=ind+1
1838           d_t(j,i)=d_t_work(ind)
1839         enddo
1840       enddo
1841       do i=nnt,nct
1842         if (itype(i).ne.10 .and. itype(i).ne.21) then
1843           do j=1,3
1844             ind=ind+1
1845             d_t(j,i+nres)=d_t_work(ind)
1846           enddo
1847         endif
1848       enddo
1849 c      call kinetic(EK)
1850 c      write (iout,*) "Kinetic energy",Ek,EK1," kinetic temperature",
1851 c     &  2.0d0/(dimen3*Rb)*EK,2.0d0/(dimen3*Rb)*EK1
1852 c      call flush(iout)
1853       return
1854       end
1855 #ifndef LANG0
1856 c-----------------------------------------------------------
1857       subroutine sd_verlet_p_setup
1858 c Sets up the parameters of stochastic Verlet algorithm       
1859       implicit real*8 (a-h,o-z)
1860       include 'DIMENSIONS'
1861 #ifdef MPI
1862       include 'mpif.h'
1863 #endif
1864       include 'COMMON.CONTROL'
1865       include 'COMMON.VAR'
1866       include 'COMMON.MD'
1867 #ifndef LANG0
1868       include 'COMMON.LANGEVIN'
1869 #else
1870       include 'COMMON.LANGEVIN.lang0'
1871 #endif
1872       include 'COMMON.CHAIN'
1873       include 'COMMON.DERIV'
1874       include 'COMMON.GEO'
1875       include 'COMMON.LOCAL'
1876       include 'COMMON.INTERACT'
1877       include 'COMMON.IOUNITS'
1878       include 'COMMON.NAMES'
1879       include 'COMMON.TIME1'
1880       double precision emgdt(MAXRES6),
1881      & pterm,vterm,rho,rhoc,vsig,
1882      & pfric_vec(MAXRES6),vfric_vec(MAXRES6),
1883      & afric_vec(MAXRES6),prand_vec(MAXRES6),
1884      & vrand_vec1(MAXRES6),vrand_vec2(MAXRES6)
1885       logical lprn /.false./
1886       double precision zero /1.0d-8/, gdt_radius /0.05d0/ 
1887       double precision ktm
1888 #ifdef MPI
1889       tt0 = MPI_Wtime()
1890 #else
1891       tt0 = tcpu()
1892 #endif
1893 c
1894 c AL 8/17/04 Code adapted from tinker
1895 c
1896 c Get the frictional and random terms for stochastic dynamics in the
1897 c eigenspace of mass-scaled UNRES friction matrix
1898 c
1899       do i = 1, dimen
1900             gdt = fricgam(i) * d_time
1901 c
1902 c Stochastic dynamics reduces to simple MD for zero friction
1903 c
1904             if (gdt .le. zero) then
1905                pfric_vec(i) = 1.0d0
1906                vfric_vec(i) = d_time
1907                afric_vec(i) = 0.5d0 * d_time * d_time
1908                prand_vec(i) = 0.0d0
1909                vrand_vec1(i) = 0.0d0
1910                vrand_vec2(i) = 0.0d0
1911 c
1912 c Analytical expressions when friction coefficient is large
1913 c
1914             else 
1915                if (gdt .ge. gdt_radius) then
1916                   egdt = dexp(-gdt)
1917                   pfric_vec(i) = egdt
1918                   vfric_vec(i) = (1.0d0-egdt) / fricgam(i)
1919                   afric_vec(i) = (d_time-vfric_vec(i)) / fricgam(i)
1920                   pterm = 2.0d0*gdt - 3.0d0 + (4.0d0-egdt)*egdt
1921                   vterm = 1.0d0 - egdt**2
1922                   rho = (1.0d0-egdt)**2 / sqrt(pterm*vterm)
1923 c
1924 c Use series expansions when friction coefficient is small
1925 c
1926                else
1927                   gdt2 = gdt * gdt
1928                   gdt3 = gdt * gdt2
1929                   gdt4 = gdt2 * gdt2
1930                   gdt5 = gdt2 * gdt3
1931                   gdt6 = gdt3 * gdt3
1932                   gdt7 = gdt3 * gdt4
1933                   gdt8 = gdt4 * gdt4
1934                   gdt9 = gdt4 * gdt5
1935                   afric_vec(i) = (gdt2/2.0d0 - gdt3/6.0d0 + gdt4/24.0d0
1936      &                          - gdt5/120.0d0 + gdt6/720.0d0
1937      &                          - gdt7/5040.0d0 + gdt8/40320.0d0
1938      &                          - gdt9/362880.0d0) / fricgam(i)**2
1939                   vfric_vec(i) = d_time - fricgam(i)*afric_vec(i)
1940                   pfric_vec(i) = 1.0d0 - fricgam(i)*vfric_vec(i)
1941                   pterm = 2.0d0*gdt3/3.0d0 - gdt4/2.0d0
1942      &                       + 7.0d0*gdt5/30.0d0 - gdt6/12.0d0
1943      &                       + 31.0d0*gdt7/1260.0d0 - gdt8/160.0d0
1944      &                       + 127.0d0*gdt9/90720.0d0
1945                   vterm = 2.0d0*gdt - 2.0d0*gdt2 + 4.0d0*gdt3/3.0d0
1946      &                       - 2.0d0*gdt4/3.0d0 + 4.0d0*gdt5/15.0d0
1947      &                       - 4.0d0*gdt6/45.0d0 + 8.0d0*gdt7/315.0d0
1948      &                       - 2.0d0*gdt8/315.0d0 + 4.0d0*gdt9/2835.0d0
1949                   rho = sqrt(3.0d0) * (0.5d0 - 3.0d0*gdt/16.0d0
1950      &                       - 17.0d0*gdt2/1280.0d0
1951      &                       + 17.0d0*gdt3/6144.0d0
1952      &                       + 40967.0d0*gdt4/34406400.0d0
1953      &                       - 57203.0d0*gdt5/275251200.0d0
1954      &                       - 1429487.0d0*gdt6/13212057600.0d0)
1955                end if
1956 c
1957 c Compute the scaling factors of random terms for the nonzero friction case
1958 c
1959                ktm = 0.5d0*d_time/fricgam(i)
1960                psig = dsqrt(ktm*pterm) / fricgam(i)
1961                vsig = dsqrt(ktm*vterm)
1962                rhoc = dsqrt(1.0d0 - rho*rho)
1963                prand_vec(i) = psig 
1964                vrand_vec1(i) = vsig * rho 
1965                vrand_vec2(i) = vsig * rhoc
1966             end if
1967       end do
1968       if (lprn) then
1969       write (iout,*) 
1970      &  "pfric_vec, vfric_vec, afric_vec, prand_vec, vrand_vec1,",
1971      &  " vrand_vec2"
1972       do i=1,dimen
1973         write (iout,'(i5,6e15.5)') i,pfric_vec(i),vfric_vec(i),
1974      &      afric_vec(i),prand_vec(i),vrand_vec1(i),vrand_vec2(i)
1975       enddo
1976       endif
1977 c
1978 c Transform from the eigenspace of mass-scaled friction matrix to UNRES variables
1979 c
1980 #ifndef   LANG0
1981       call eigtransf(dimen,maxres2,mt3,mt2,pfric_vec,pfric_mat)
1982       call eigtransf(dimen,maxres2,mt3,mt2,vfric_vec,vfric_mat)
1983       call eigtransf(dimen,maxres2,mt3,mt2,afric_vec,afric_mat)
1984       call eigtransf(dimen,maxres2,mt3,mt1,prand_vec,prand_mat)
1985       call eigtransf(dimen,maxres2,mt3,mt1,vrand_vec1,vrand_mat1)
1986       call eigtransf(dimen,maxres2,mt3,mt1,vrand_vec2,vrand_mat2)
1987 #endif
1988 #ifdef MPI
1989       t_sdsetup=t_sdsetup+MPI_Wtime()
1990 #else
1991       t_sdsetup=t_sdsetup+tcpu()-tt0
1992 #endif
1993       return
1994       end
1995 c-------------------------------------------------------------      
1996       subroutine eigtransf1(n,ndim,ab,d,c)
1997       implicit none
1998       integer n,ndim
1999       double precision ab(ndim,ndim,n),c(ndim,n),d(ndim)
2000       integer i,j,k
2001       do i=1,n
2002         do j=1,n
2003           c(i,j)=0.0d0
2004           do k=1,n
2005             c(i,j)=c(i,j)+ab(k,j,i)*d(k)
2006           enddo
2007         enddo
2008       enddo
2009       return
2010       end
2011 c-------------------------------------------------------------      
2012       subroutine eigtransf(n,ndim,a,b,d,c)
2013       implicit none
2014       integer n,ndim
2015       double precision a(ndim,n),b(ndim,n),c(ndim,n),d(ndim)
2016       integer i,j,k
2017       do i=1,n
2018         do j=1,n
2019           c(i,j)=0.0d0
2020           do k=1,n
2021             c(i,j)=c(i,j)+a(i,k)*b(k,j)*d(k)
2022           enddo
2023         enddo
2024       enddo
2025       return
2026       end
2027 c-------------------------------------------------------------      
2028       subroutine sd_verlet1
2029 c Applying stochastic velocity Verlet algorithm - step 1 to velocities        
2030       implicit real*8 (a-h,o-z)
2031       include 'DIMENSIONS'
2032       include 'COMMON.CONTROL'
2033       include 'COMMON.VAR'
2034       include 'COMMON.MD'
2035 #ifndef LANG0
2036       include 'COMMON.LANGEVIN'
2037 #else
2038       include 'COMMON.LANGEVIN.lang0'
2039 #endif
2040       include 'COMMON.CHAIN'
2041       include 'COMMON.DERIV'
2042       include 'COMMON.GEO'
2043       include 'COMMON.LOCAL'
2044       include 'COMMON.INTERACT'
2045       include 'COMMON.IOUNITS'
2046       include 'COMMON.NAMES'
2047       double precision stochforcvec(MAXRES6)
2048       common /stochcalc/ stochforcvec
2049       logical lprn /.false./
2050
2051 c      write (iout,*) "dc_old"
2052 c      do i=0,nres
2053 c        write (iout,'(i5,3f10.5,5x,3f10.5)') 
2054 c     &   i,(dc_old(j,i),j=1,3),(dc_old(j,i+nres),j=1,3)
2055 c      enddo
2056       do j=1,3
2057         dc_work(j)=dc_old(j,0)
2058         d_t_work(j)=d_t_old(j,0)
2059         d_a_work(j)=d_a_old(j,0)
2060       enddo
2061       ind=3
2062       do i=nnt,nct-1
2063         do j=1,3
2064           dc_work(ind+j)=dc_old(j,i)
2065           d_t_work(ind+j)=d_t_old(j,i)
2066           d_a_work(ind+j)=d_a_old(j,i)
2067         enddo
2068         ind=ind+3
2069       enddo
2070       do i=nnt,nct
2071         if (itype(i).ne.10 .and. itype(i).ne.21) then
2072           do j=1,3
2073             dc_work(ind+j)=dc_old(j,i+nres)
2074             d_t_work(ind+j)=d_t_old(j,i+nres)
2075             d_a_work(ind+j)=d_a_old(j,i+nres)
2076           enddo
2077           ind=ind+3
2078         endif
2079       enddo
2080 #ifndef LANG0
2081       if (lprn) then
2082       write (iout,*) 
2083      &  "pfric_mat, vfric_mat, afric_mat, prand_mat, vrand_mat1,",
2084      &  " vrand_mat2"
2085       do i=1,dimen
2086         do j=1,dimen
2087           write (iout,'(2i5,6e15.5)') i,j,pfric_mat(i,j),
2088      &      vfric_mat(i,j),afric_mat(i,j),
2089      &      prand_mat(i,j),vrand_mat1(i,j),vrand_mat2(i,j)
2090         enddo
2091       enddo
2092       endif
2093       do i=1,dimen
2094         ddt1=0.0d0
2095         ddt2=0.0d0
2096         do j=1,dimen
2097           dc_work(i)=dc_work(i)+vfric_mat(i,j)*d_t_work(j)
2098      &      +afric_mat(i,j)*d_a_work(j)+prand_mat(i,j)*stochforcvec(j)
2099           ddt1=ddt1+pfric_mat(i,j)*d_t_work(j)
2100           ddt2=ddt2+vfric_mat(i,j)*d_a_work(j)
2101         enddo
2102         d_t_work_new(i)=ddt1+0.5d0*ddt2
2103         d_t_work(i)=ddt1+ddt2
2104       enddo
2105 #endif
2106       do j=1,3
2107         dc(j,0)=dc_work(j)
2108         d_t(j,0)=d_t_work(j)
2109       enddo
2110       ind=3     
2111       do i=nnt,nct-1    
2112         do j=1,3
2113           dc(j,i)=dc_work(ind+j)
2114           d_t(j,i)=d_t_work(ind+j)
2115         enddo
2116         ind=ind+3
2117       enddo
2118       do i=nnt,nct
2119         if (itype(i).ne.10) then
2120           inres=i+nres
2121           do j=1,3
2122             dc(j,inres)=dc_work(ind+j)
2123             d_t(j,inres)=d_t_work(ind+j)
2124           enddo
2125           ind=ind+3
2126         endif      
2127       enddo 
2128       return
2129       end
2130 c--------------------------------------------------------------------------
2131       subroutine sd_verlet2
2132 c  Calculating the adjusted velocities for accelerations
2133       implicit real*8 (a-h,o-z)
2134       include 'DIMENSIONS'
2135       include 'COMMON.CONTROL'
2136       include 'COMMON.VAR'
2137       include 'COMMON.MD'
2138 #ifndef LANG0
2139       include 'COMMON.LANGEVIN'
2140 #else
2141       include 'COMMON.LANGEVIN.lang0'
2142 #endif
2143       include 'COMMON.CHAIN'
2144       include 'COMMON.DERIV'
2145       include 'COMMON.GEO'
2146       include 'COMMON.LOCAL'
2147       include 'COMMON.INTERACT'
2148       include 'COMMON.IOUNITS'
2149       include 'COMMON.NAMES'
2150       double precision stochforcvec(MAXRES6),stochforcvecV(MAXRES6)
2151       common /stochcalc/ stochforcvec
2152 c
2153 c Compute the stochastic forces which contribute to velocity change
2154 c
2155       call stochastic_force(stochforcvecV)
2156
2157 #ifndef LANG0
2158       do i=1,dimen
2159         ddt1=0.0d0
2160         ddt2=0.0d0
2161         do j=1,dimen
2162           ddt1=ddt1+vfric_mat(i,j)*d_a_work(j)
2163           ddt2=ddt2+vrand_mat1(i,j)*stochforcvec(j)+
2164      &     vrand_mat2(i,j)*stochforcvecV(j)
2165         enddo
2166         d_t_work(i)=d_t_work_new(i)+0.5d0*ddt1+ddt2
2167       enddo
2168 #endif
2169       do j=1,3
2170         d_t(j,0)=d_t_work(j)
2171       enddo
2172       ind=3
2173       do i=nnt,nct-1
2174         do j=1,3
2175           d_t(j,i)=d_t_work(ind+j)
2176         enddo
2177         ind=ind+3
2178       enddo
2179       do i=nnt,nct
2180         if (itype(i).ne.10 .and. itype(i).ne.21) then
2181           inres=i+nres
2182           do j=1,3
2183             d_t(j,inres)=d_t_work(ind+j)
2184           enddo
2185           ind=ind+3
2186         endif
2187       enddo 
2188       return
2189       end
2190 c-----------------------------------------------------------
2191       subroutine sd_verlet_ciccotti_setup
2192 c Sets up the parameters of stochastic velocity Verlet algorithmi; Ciccotti's 
2193 c version 
2194       implicit real*8 (a-h,o-z)
2195       include 'DIMENSIONS'
2196 #ifdef MPI
2197       include 'mpif.h'
2198 #endif
2199       include 'COMMON.CONTROL'
2200       include 'COMMON.VAR'
2201       include 'COMMON.MD'
2202 #ifndef LANG0
2203       include 'COMMON.LANGEVIN'
2204 #else
2205       include 'COMMON.LANGEVIN.lang0'
2206 #endif
2207       include 'COMMON.CHAIN'
2208       include 'COMMON.DERIV'
2209       include 'COMMON.GEO'
2210       include 'COMMON.LOCAL'
2211       include 'COMMON.INTERACT'
2212       include 'COMMON.IOUNITS'
2213       include 'COMMON.NAMES'
2214       include 'COMMON.TIME1'
2215       double precision emgdt(MAXRES6),
2216      & pterm,vterm,rho,rhoc,vsig,
2217      & pfric_vec(MAXRES6),vfric_vec(MAXRES6),
2218      & afric_vec(MAXRES6),prand_vec(MAXRES6),
2219      & vrand_vec1(MAXRES6),vrand_vec2(MAXRES6)
2220       logical lprn /.false./
2221       double precision zero /1.0d-8/, gdt_radius /0.05d0/ 
2222       double precision ktm
2223 #ifdef MPI
2224       tt0 = MPI_Wtime()
2225 #else
2226       tt0 = tcpu()
2227 #endif
2228 c
2229 c AL 8/17/04 Code adapted from tinker
2230 c
2231 c Get the frictional and random terms for stochastic dynamics in the
2232 c eigenspace of mass-scaled UNRES friction matrix
2233 c
2234       do i = 1, dimen
2235             write (iout,*) "i",i," fricgam",fricgam(i)
2236             gdt = fricgam(i) * d_time
2237 c
2238 c Stochastic dynamics reduces to simple MD for zero friction
2239 c
2240             if (gdt .le. zero) then
2241                pfric_vec(i) = 1.0d0
2242                vfric_vec(i) = d_time
2243                afric_vec(i) = 0.5d0*d_time*d_time
2244                prand_vec(i) = afric_vec(i)
2245                vrand_vec2(i) = vfric_vec(i)
2246 c
2247 c Analytical expressions when friction coefficient is large
2248 c
2249             else 
2250                egdt = dexp(-gdt)
2251                pfric_vec(i) = egdt
2252                vfric_vec(i) = dexp(-0.5d0*gdt)*d_time
2253                afric_vec(i) = 0.5d0*dexp(-0.25d0*gdt)*d_time*d_time
2254                prand_vec(i) = afric_vec(i)
2255                vrand_vec2(i) = vfric_vec(i)
2256 c
2257 c Compute the scaling factors of random terms for the nonzero friction case
2258 c
2259 c               ktm = 0.5d0*d_time/fricgam(i)
2260 c               psig = dsqrt(ktm*pterm) / fricgam(i)
2261 c               vsig = dsqrt(ktm*vterm)
2262 c               prand_vec(i) = psig*afric_vec(i) 
2263 c               vrand_vec2(i) = vsig*vfric_vec(i)
2264             end if
2265       end do
2266       if (lprn) then
2267       write (iout,*) 
2268      &  "pfric_vec, vfric_vec, afric_vec, prand_vec, vrand_vec1,",
2269      &  " vrand_vec2"
2270       do i=1,dimen
2271         write (iout,'(i5,6e15.5)') i,pfric_vec(i),vfric_vec(i),
2272      &      afric_vec(i),prand_vec(i),vrand_vec1(i),vrand_vec2(i)
2273       enddo
2274       endif
2275 c
2276 c Transform from the eigenspace of mass-scaled friction matrix to UNRES variables
2277 c
2278       call eigtransf(dimen,maxres2,mt3,mt2,pfric_vec,pfric_mat)
2279       call eigtransf(dimen,maxres2,mt3,mt2,vfric_vec,vfric_mat)
2280       call eigtransf(dimen,maxres2,mt3,mt2,afric_vec,afric_mat)
2281       call eigtransf(dimen,maxres2,mt3,mt1,prand_vec,prand_mat)
2282       call eigtransf(dimen,maxres2,mt3,mt1,vrand_vec2,vrand_mat2)
2283 #ifdef MPI
2284       t_sdsetup=t_sdsetup+MPI_Wtime()
2285 #else
2286       t_sdsetup=t_sdsetup+tcpu()-tt0
2287 #endif
2288       return
2289       end
2290 c-------------------------------------------------------------      
2291       subroutine sd_verlet1_ciccotti
2292 c Applying stochastic velocity Verlet algorithm - step 1 to velocities        
2293       implicit real*8 (a-h,o-z)
2294       include 'DIMENSIONS'
2295 #ifdef MPI
2296       include 'mpif.h'
2297 #endif
2298       include 'COMMON.CONTROL'
2299       include 'COMMON.VAR'
2300       include 'COMMON.MD'
2301 #ifndef LANG0
2302       include 'COMMON.LANGEVIN'
2303 #else
2304       include 'COMMON.LANGEVIN.lang0'
2305 #endif
2306       include 'COMMON.CHAIN'
2307       include 'COMMON.DERIV'
2308       include 'COMMON.GEO'
2309       include 'COMMON.LOCAL'
2310       include 'COMMON.INTERACT'
2311       include 'COMMON.IOUNITS'
2312       include 'COMMON.NAMES'
2313       double precision stochforcvec(MAXRES6)
2314       common /stochcalc/ stochforcvec
2315       logical lprn /.false./
2316
2317 c      write (iout,*) "dc_old"
2318 c      do i=0,nres
2319 c        write (iout,'(i5,3f10.5,5x,3f10.5)') 
2320 c     &   i,(dc_old(j,i),j=1,3),(dc_old(j,i+nres),j=1,3)
2321 c      enddo
2322       do j=1,3
2323         dc_work(j)=dc_old(j,0)
2324         d_t_work(j)=d_t_old(j,0)
2325         d_a_work(j)=d_a_old(j,0)
2326       enddo
2327       ind=3
2328       do i=nnt,nct-1
2329         do j=1,3
2330           dc_work(ind+j)=dc_old(j,i)
2331           d_t_work(ind+j)=d_t_old(j,i)
2332           d_a_work(ind+j)=d_a_old(j,i)
2333         enddo
2334         ind=ind+3
2335       enddo
2336       do i=nnt,nct
2337         if (itype(i).ne.10 .and. itype(i).ne.21) then
2338           do j=1,3
2339             dc_work(ind+j)=dc_old(j,i+nres)
2340             d_t_work(ind+j)=d_t_old(j,i+nres)
2341             d_a_work(ind+j)=d_a_old(j,i+nres)
2342           enddo
2343           ind=ind+3
2344         endif
2345       enddo
2346
2347 #ifndef LANG0
2348       if (lprn) then
2349       write (iout,*) 
2350      &  "pfric_mat, vfric_mat, afric_mat, prand_mat, vrand_mat1,",
2351      &  " vrand_mat2"
2352       do i=1,dimen
2353         do j=1,dimen
2354           write (iout,'(2i5,6e15.5)') i,j,pfric_mat(i,j),
2355      &      vfric_mat(i,j),afric_mat(i,j),
2356      &      prand_mat(i,j),vrand_mat1(i,j),vrand_mat2(i,j)
2357         enddo
2358       enddo
2359       endif
2360       do i=1,dimen
2361         ddt1=0.0d0
2362         ddt2=0.0d0
2363         do j=1,dimen
2364           dc_work(i)=dc_work(i)+vfric_mat(i,j)*d_t_work(j)
2365      &      +afric_mat(i,j)*d_a_work(j)+prand_mat(i,j)*stochforcvec(j)
2366           ddt1=ddt1+pfric_mat(i,j)*d_t_work(j)
2367           ddt2=ddt2+vfric_mat(i,j)*d_a_work(j)
2368         enddo
2369         d_t_work_new(i)=ddt1+0.5d0*ddt2
2370         d_t_work(i)=ddt1+ddt2
2371       enddo
2372 #endif
2373       do j=1,3
2374         dc(j,0)=dc_work(j)
2375         d_t(j,0)=d_t_work(j)
2376       enddo
2377       ind=3     
2378       do i=nnt,nct-1    
2379         do j=1,3
2380           dc(j,i)=dc_work(ind+j)
2381           d_t(j,i)=d_t_work(ind+j)
2382         enddo
2383         ind=ind+3
2384       enddo
2385       do i=nnt,nct
2386         if (itype(i).ne.10 .and. itype(i).ne.21) then
2387           inres=i+nres
2388           do j=1,3
2389             dc(j,inres)=dc_work(ind+j)
2390             d_t(j,inres)=d_t_work(ind+j)
2391           enddo
2392           ind=ind+3
2393         endif      
2394       enddo 
2395       return
2396       end
2397 c--------------------------------------------------------------------------
2398       subroutine sd_verlet2_ciccotti
2399 c  Calculating the adjusted velocities for accelerations
2400       implicit real*8 (a-h,o-z)
2401       include 'DIMENSIONS'
2402       include 'COMMON.CONTROL'
2403       include 'COMMON.VAR'
2404       include 'COMMON.MD'
2405 #ifndef LANG0
2406       include 'COMMON.LANGEVIN'
2407 #else
2408       include 'COMMON.LANGEVIN.lang0'
2409 #endif
2410       include 'COMMON.CHAIN'
2411       include 'COMMON.DERIV'
2412       include 'COMMON.GEO'
2413       include 'COMMON.LOCAL'
2414       include 'COMMON.INTERACT'
2415       include 'COMMON.IOUNITS'
2416       include 'COMMON.NAMES'
2417       double precision stochforcvec(MAXRES6),stochforcvecV(MAXRES6)
2418       common /stochcalc/ stochforcvec
2419 c
2420 c Compute the stochastic forces which contribute to velocity change
2421 c
2422       call stochastic_force(stochforcvecV)
2423 #ifndef LANG0
2424       do i=1,dimen
2425         ddt1=0.0d0
2426         ddt2=0.0d0
2427         do j=1,dimen
2428
2429           ddt1=ddt1+vfric_mat(i,j)*d_a_work(j)
2430 c          ddt2=ddt2+vrand_mat2(i,j)*stochforcvecV(j)
2431           ddt2=ddt2+vrand_mat2(i,j)*stochforcvec(j)
2432         enddo
2433         d_t_work(i)=d_t_work_new(i)+0.5d0*ddt1+ddt2
2434       enddo
2435 #endif
2436       do j=1,3
2437         d_t(j,0)=d_t_work(j)
2438       enddo
2439       ind=3
2440       do i=nnt,nct-1
2441         do j=1,3
2442           d_t(j,i)=d_t_work(ind+j)
2443         enddo
2444         ind=ind+3
2445       enddo
2446       do i=nnt,nct
2447         if (itype(i).ne.10 .and. itype(i).ne.21) then
2448           inres=i+nres
2449           do j=1,3
2450             d_t(j,inres)=d_t_work(ind+j)
2451           enddo
2452           ind=ind+3
2453         endif
2454       enddo 
2455       return
2456       end
2457 #endif