Merge branch 'master' into rotation

[gromacs/adressmacs.git] / src / mdlib / sim_util.c

/* -*- mode: c; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; c-file-style: "stroustrup"; -*-
 *
 * 
 *                This source code is part of
 * 
 *                 G   R   O   M   A   C   S
 * 
 *          GROningen MAchine for Chemical Simulations
 * 
 *                        VERSION 3.2.0
 * Written by David van der Spoel, Erik Lindahl, Berk Hess, and others.
 * Copyright (c) 1991-2000, University of Groningen, The Netherlands.
 * Copyright (c) 2001-2004, The GROMACS development team,
 * check out http://www.gromacs.org for more information.

 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * If you want to redistribute modifications, please consider that
 * scientific software is very special. Version control is crucial -
 * bugs must be traceable. We will be happy to consider code for
 * inclusion in the official distribution, but derived work must not
 * be called official GROMACS. Details are found in the README & COPYING
 * files - if they are missing, get the official version at www.gromacs.org.
 * 
 * To help us fund GROMACS development, we humbly ask that you cite
 * the papers on the package - you can find them in the top README file.
 * 
 * For more info, check our website at http://www.gromacs.org
 * 
 * And Hey:
 * GROwing Monsters And Cloning Shrimps
 */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef GMX_CRAY_XT3
#include<catamount/dclock.h>
#endif


#include <stdio.h>
#include <time.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#include <math.h>
#include "typedefs.h"
#include "string2.h"
#include "gmxfio.h"
#include "smalloc.h"
#include "names.h"
#include "confio.h"
#include "mvdata.h"
#include "txtdump.h"
#include "pbc.h"
#include "vec.h"
#include "time.h"
#include "nrnb.h"
#include "mshift.h"
#include "mdrun.h"
#include "update.h"
#include "physics.h"
#include "main.h"
#include "mdatoms.h"
#include "force.h"
#include "bondf.h"
#include "pme.h"
#include "pppm.h"
#include "disre.h"
#include "orires.h"
#include "network.h"
#include "calcmu.h"
#include "constr.h"
#include "xvgr.h"
#include "trnio.h"
#include "xtcio.h"
#include "copyrite.h"
#include "pull_rotation.h"
#include "mpelogging.h"
#include "domdec.h"
#include "partdec.h"
#include "gmx_wallcycle.h"
#include "genborn.h"

#ifdef GMX_LIB_MPI
#include <mpi.h>
#endif
#ifdef GMX_THREADS
#include "tmpi.h"
#endif


#include "qmmm.h"

#if 0
typedef struct gmx_timeprint {
    
} t_gmx_timeprint;
#endif


double
gmx_gettime()
{
#ifdef HAVE_GETTIMEOFDAY
        struct timeval t;
        struct timezone tz = { 0,0 };
        double seconds;
        
        gettimeofday(&t,&tz);
        
        seconds = (double) t.tv_sec + 1e-6*(double)t.tv_usec;
        
        return seconds;
#else
        double  seconds;
        
        seconds = time(NULL);
        
        return seconds;
#endif
}


#define difftime(end,start) ((double)(end)-(double)(start))

void print_time(FILE *out,gmx_runtime_t *runtime,gmx_large_int_t step,t_inputrec *ir)
{
  time_t finish;

  double dt;
  char buf[48];

  if (!gmx_parallel_env())
    fprintf(out,"\r");
  fprintf(out,"step %s",gmx_step_str(step,buf));
  if ((step >= ir->nstlist)) {
    if ((ir->nstlist == 0) || ((step % ir->nstlist) == 0)) {
      /* We have done a full cycle let's update time_per_step */
      runtime->last = gmx_gettime();
      dt = difftime(runtime->last,runtime->real);
      runtime->time_per_step = dt/(step - ir->init_step + 1);
    }
    dt = (ir->nsteps + ir->init_step - step)*runtime->time_per_step;

    if (dt >= 300) {    
      finish = (time_t) (runtime->last + dt);
      sprintf(buf,"%s",ctime(&finish));
      buf[strlen(buf)-1]='\0';
      fprintf(out,", will finish %s",buf);
    }
    else
      fprintf(out,", remaining runtime: %5d s          ",(int)dt);
  }
  if (gmx_parallel_env())
    fprintf(out,"\n");

  fflush(out);
}

#ifdef NO_CLOCK 
#define clock() -1
#endif

static double set_proctime(gmx_runtime_t *runtime)
{
    double diff;
#ifdef GMX_CRAY_XT3
    double prev;

    prev = runtime->proc;
    runtime->proc = dclock();
    
    diff = runtime->proc - prev;
#else
    clock_t prev;

    prev = runtime->proc;
    runtime->proc = clock();

    diff = (double)(runtime->proc - prev)/(double)CLOCKS_PER_SEC;
#endif
    if (diff < 0)
    {
        /* The counter has probably looped, ignore this data */
        diff = 0;
    }

    return diff;
}

void runtime_start(gmx_runtime_t *runtime)
{
    runtime->real = gmx_gettime();
    runtime->proc          = 0;
    set_proctime(runtime);
    runtime->realtime      = 0;
    runtime->proctime      = 0;
    runtime->last          = 0;
    runtime->time_per_step = 0;
}

void runtime_end(gmx_runtime_t *runtime)
{
    double now;
    
    now = gmx_gettime();
    
    runtime->proctime += set_proctime(runtime);
    runtime->realtime  = now - runtime->real;
    runtime->real      = now;
}

void runtime_upd_proc(gmx_runtime_t *runtime)
{
    runtime->proctime += set_proctime(runtime);
}

void print_date_and_time(FILE *fplog,int nodeid,const char *title,
                         const gmx_runtime_t *runtime)
{
    int i;
    char *ts,time_string[STRLEN];
    time_t tmptime;

    if (runtime != NULL)
    {
                tmptime = (time_t) runtime->real;
        ts = ctime(&tmptime);
    }
    else
    {
        tmptime = (time_t) gmx_gettime();
        ts = ctime(&tmptime);
    }
    for(i=0; ts[i]>=' '; i++)
    {
        time_string[i]=ts[i];
    }
    time_string[i]='\0';
    if (fplog)
    {
        fprintf(fplog,"%s on node %d %s\n",title,nodeid,time_string);
    }
}

static void sum_forces(int start,int end,rvec f[],rvec flr[])
{
  int i;
  
  if (gmx_debug_at) {
    pr_rvecs(debug,0,"fsr",f+start,end-start);
    pr_rvecs(debug,0,"flr",flr+start,end-start);
  }
  for(i=start; (i<end); i++)
    rvec_inc(f[i],flr[i]);
}

/* 
 * calc_f_el calculates forces due to an electric field.
 *
 * force is kJ mol^-1 nm^-1 = e * kJ mol^-1 nm^-1 / e 
 *
 * Et[] contains the parameters for the time dependent 
 * part of the field (not yet used). 
 * Ex[] contains the parameters for
 * the spatial dependent part of the field. You can have cool periodic
 * fields in principle, but only a constant field is supported
 * now. 
 * The function should return the energy due to the electric field
 * (if any) but for now returns 0.
 *
 * WARNING:
 * There can be problems with the virial.
 * Since the field is not self-consistent this is unavoidable.
 * For neutral molecules the virial is correct within this approximation.
 * For neutral systems with many charged molecules the error is small.
 * But for systems with a net charge or a few charged molecules
 * the error can be significant when the field is high.
 * Solution: implement a self-consitent electric field into PME.
 */
static void calc_f_el(FILE *fp,int  start,int homenr,
                      real charge[],rvec x[],rvec f[],
                      t_cosines Ex[],t_cosines Et[],double t)
{
    rvec Ext;
    real t0;
    int  i,m;
    
    for(m=0; (m<DIM); m++)
    {
        if (Et[m].n > 0)
        {
            if (Et[m].n == 3)
            {
                t0 = Et[m].a[1];
                Ext[m] = cos(Et[m].a[0]*(t-t0))*exp(-sqr(t-t0)/(2.0*sqr(Et[m].a[2])));
            }
            else
            {
                Ext[m] = cos(Et[m].a[0]*t);
            }
        }
        else
        {
            Ext[m] = 1.0;
        }
        if (Ex[m].n > 0)
        {
            /* Convert the field strength from V/nm to MD-units */
            Ext[m] *= Ex[m].a[0]*FIELDFAC;
            for(i=start; (i<start+homenr); i++)
                f[i][m] += charge[i]*Ext[m];
        }
        else
        {
            Ext[m] = 0;
        }
    }
    if (fp != NULL)
    {
        fprintf(fp,"%10g  %10g  %10g  %10g #FIELD\n",t,
                Ext[XX]/FIELDFAC,Ext[YY]/FIELDFAC,Ext[ZZ]/FIELDFAC);
    }
}

static void calc_virial(FILE *fplog,int start,int homenr,rvec x[],rvec f[],
                        tensor vir_part,t_graph *graph,matrix box,
                        t_nrnb *nrnb,const t_forcerec *fr,int ePBC)
{
  int i,j;
  tensor virtest;

  /* The short-range virial from surrounding boxes */
  clear_mat(vir_part);
  calc_vir(fplog,SHIFTS,fr->shift_vec,fr->fshift,vir_part,ePBC==epbcSCREW,box);
  inc_nrnb(nrnb,eNR_VIRIAL,SHIFTS);
  
  /* Calculate partial virial, for local atoms only, based on short range. 
   * Total virial is computed in global_stat, called from do_md 
   */
  f_calc_vir(fplog,start,start+homenr,x,f,vir_part,graph,box);
  inc_nrnb(nrnb,eNR_VIRIAL,homenr);

  /* Add position restraint contribution */
  for(i=0; i<DIM; i++) {
    vir_part[i][i] += fr->vir_diag_posres[i];
  }

  /* Add wall contribution */
  for(i=0; i<DIM; i++) {
    vir_part[i][ZZ] += fr->vir_wall_z[i];
  }

  if (debug)
    pr_rvecs(debug,0,"vir_part",vir_part,DIM);
}

static void print_large_forces(FILE *fp,t_mdatoms *md,t_commrec *cr,
                               gmx_large_int_t step,real pforce,rvec *x,rvec *f)
{
  int  i;
  real pf2,fn2;
  char buf[22];

  pf2 = sqr(pforce);
  for(i=md->start; i<md->start+md->homenr; i++) {
    fn2 = norm2(f[i]);
    if (fn2 >= pf2) {
      fprintf(fp,"step %s  atom %6d  x %8.3f %8.3f %8.3f  force %12.5e\n",
              gmx_step_str(step,buf),
              ddglatnr(cr->dd,i),x[i][XX],x[i][YY],x[i][ZZ],sqrt(fn2));
    }
  }
}

void do_force(FILE *fplog,t_commrec *cr,
              t_inputrec *inputrec,
              gmx_large_int_t step,t_nrnb *nrnb,gmx_wallcycle_t wcycle,
              gmx_localtop_t *top,
              gmx_mtop_t *mtop,
              gmx_groups_t *groups,
              matrix box,rvec x[],history_t *hist,
              rvec f[],
              tensor vir_force,
              t_mdatoms *mdatoms,
              gmx_enerdata_t *enerd,t_fcdata *fcd,
              real lambda,t_graph *graph,
              t_forcerec *fr,gmx_vsite_t *vsite,rvec mu_tot,
              double t,FILE *field,gmx_edsam_t ed,
              bool bBornRadii,
              int flags)
{
    int    cg0,cg1,i,j;
    int    start,homenr;
    double mu[2*DIM]; 
    bool   bSepDVDL,bStateChanged,bNS,bFillGrid,bCalcCGCM,bBS;
    bool   bDoLongRange,bDoForces,bSepLRF;
    matrix boxs;
    real   e,v,dvdl;
    t_pbc  pbc;
    float  cycles_ppdpme,cycles_pme,cycles_seppme,cycles_force;
  
    start  = mdatoms->start;
    homenr = mdatoms->homenr;

    bSepDVDL = (fr->bSepDVDL && do_per_step(step,inputrec->nstlog));

    clear_mat(vir_force);

    if (PARTDECOMP(cr))
    {
        pd_cg_range(cr,&cg0,&cg1);
    }
    else
    {
        cg0 = 0;
        if (DOMAINDECOMP(cr))
        {
            cg1 = cr->dd->ncg_tot;
        }
        else
        {
            cg1 = top->cgs.nr;
        }
        if (fr->n_tpi > 0)
        {
            cg1--;
        }
    }

    bStateChanged = (flags & GMX_FORCE_STATECHANGED);
    bNS           = (flags & GMX_FORCE_NS) && (fr->bAllvsAll==FALSE); 
    bFillGrid     = (bNS && bStateChanged);
    bCalcCGCM     = (bFillGrid && !DOMAINDECOMP(cr));
    bDoLongRange  = (fr->bTwinRange && bNS && (flags & GMX_FORCE_DOLR));
    bDoForces     = (flags & GMX_FORCE_FORCES);
    bSepLRF       = (bDoLongRange && bDoForces && (flags & GMX_FORCE_SEPLRF));

    if (bStateChanged)
    {
        update_forcerec(fplog,fr,box);
        
        /* Calculate total (local) dipole moment in a temporary common array. 
         * This makes it possible to sum them over nodes faster.
         */
        calc_mu(start,homenr,
                x,mdatoms->chargeA,mdatoms->chargeB,mdatoms->nChargePerturbed,
                mu,mu+DIM);
    }
  
  if (fr->ePBC != epbcNONE) { 
    /* Compute shift vectors every step,
     * because of pressure coupling or box deformation!
     */
    if (DYNAMIC_BOX(*inputrec) && bStateChanged)
      calc_shifts(box,fr->shift_vec);
    
    if (bCalcCGCM) { 
      put_charge_groups_in_box(fplog,cg0,cg1,fr->ePBC,box,
                               &(top->cgs),x,fr->cg_cm);
      inc_nrnb(nrnb,eNR_CGCM,homenr);
      inc_nrnb(nrnb,eNR_RESETX,cg1-cg0);
    } 
    else if (EI_ENERGY_MINIMIZATION(inputrec->eI) && graph) {
      unshift_self(graph,box,x);
    }
  } 
  else if (bCalcCGCM) {
    calc_cgcm(fplog,cg0,cg1,&(top->cgs),x,fr->cg_cm);
    inc_nrnb(nrnb,eNR_CGCM,homenr);
  }
  
  if (bCalcCGCM) {
    if (PAR(cr)) {
      move_cgcm(fplog,cr,fr->cg_cm);
    }
    if (gmx_debug_at)
      pr_rvecs(debug,0,"cgcm",fr->cg_cm,top->cgs.nr);
  }

#ifdef GMX_MPI
  if (!(cr->duty & DUTY_PME)) {
    /* Send particle coordinates to the pme nodes.
     * Since this is only implemented for domain decomposition
     * and domain decomposition does not use the graph,
     * we do not need to worry about shifting.
     */    

    wallcycle_start(wcycle,ewcPP_PMESENDX);
    GMX_MPE_LOG(ev_send_coordinates_start);

    bBS = (inputrec->nwall == 2);
    if (bBS) {
      copy_mat(box,boxs);
      svmul(inputrec->wall_ewald_zfac,boxs[ZZ],boxs[ZZ]);
    }

    gmx_pme_send_x(cr,bBS ? boxs : box,x,mdatoms->nChargePerturbed,lambda,step);

    GMX_MPE_LOG(ev_send_coordinates_finish);
    wallcycle_stop(wcycle,ewcPP_PMESENDX);
  }
#endif /* GMX_MPI */

    /* Communicate coordinates and sum dipole if necessary */
    if (PAR(cr))
    {
        wallcycle_start(wcycle,ewcMOVEX);
        if (DOMAINDECOMP(cr))
        {
            dd_move_x(cr->dd,box,x);
        }
        else
        {
            move_x(fplog,cr,GMX_LEFT,GMX_RIGHT,x,nrnb);
        }
        /* When we don't need the total dipole we sum it in global_stat */
        if (bStateChanged && NEED_MUTOT(*inputrec))
        {
            gmx_sumd(2*DIM,mu,cr);
        }
        wallcycle_stop(wcycle,ewcMOVEX);
    }
    if (bStateChanged)
    {
        for(i=0; i<2; i++)
        {
            for(j=0;j<DIM;j++)
            {
                fr->mu_tot[i][j] = mu[i*DIM + j];
            }
        }
    }
    if (fr->efep == efepNO)
    {
        copy_rvec(fr->mu_tot[0],mu_tot);
    }
    else
    {
        for(j=0; j<DIM; j++)
        {
            mu_tot[j] =
                (1.0 - lambda)*fr->mu_tot[0][j] + lambda*fr->mu_tot[1][j];
        }
    }

    /* Reset energies */
    reset_enerdata(&(inputrec->opts),fr,bNS,enerd,MASTER(cr));
    clear_rvecs(SHIFTS,fr->fshift);

    if (bNS)
    {
        wallcycle_start(wcycle,ewcNS);
        
        if (graph && bStateChanged)
        {
            /* Calculate intramolecular shift vectors to make molecules whole */
            mk_mshift(fplog,graph,fr->ePBC,box,x);
        }

        /* Reset long range forces if necessary */
        if (fr->bTwinRange)
        {
            /* Reset the (long-range) forces if necessary */
            clear_rvecs(fr->natoms_force,bSepLRF ? fr->f_twin : f);
        }

        /* Do the actual neighbour searching and if twin range electrostatics
         * also do the calculation of long range forces and energies.
         */
        dvdl = 0; 
        ns(fplog,fr,x,box,
           groups,&(inputrec->opts),top,mdatoms,
           cr,nrnb,lambda,&dvdl,&enerd->grpp,bFillGrid,
           bDoLongRange,bDoForces,bSepLRF ? fr->f_twin : f);
        if (bSepDVDL)
        {
            fprintf(fplog,sepdvdlformat,"LR non-bonded",0.0,dvdl);
        }
        enerd->dvdl_lin += dvdl;
        
        wallcycle_stop(wcycle,ewcNS);
    }
        
    if (inputrec->implicit_solvent && bNS) 
    {
        make_gb_nblist(cr,mtop->natoms,inputrec->gb_algorithm,inputrec->rlist,
                       x,box,fr,&top->idef,graph,fr->born);
    }
        
    if (DOMAINDECOMP(cr))
    {
        if (!(cr->duty & DUTY_PME))
        {
            wallcycle_start(wcycle,ewcPPDURINGPME);
            dd_force_flop_start(cr->dd,nrnb);
        }
    }
    
    if (inputrec->bRot)
    {
        /* Enforced rotation has its own cycle counter that starts after the collective
         * coordinates have been communicated. It is added to ddCyclF */
        do_rotation(cr,inputrec,box,x,t,step,wcycle,bNS);
    }

    /* Start the force cycle counter.
     * This counter is stopped in do_forcelow_level.
     * No parallel communication should occur while this counter is running,
     * since that will interfere with the dynamic load balancing.
     */
    wallcycle_start(wcycle,ewcFORCE);
    GMX_MPE_LOG(ev_forcecycles_start);

    if (bDoForces)
    {
        /* Reset forces for which the virial is calculated separately:
         * PME/Ewald forces if necessary */
        if (fr->bF_NoVirSum) 
        {
            if (flags & GMX_FORCE_VIRIAL)
            {
                fr->f_novirsum = fr->f_novirsum_alloc;
                GMX_BARRIER(cr->mpi_comm_mygroup);
                if (fr->bDomDec)
                {
                    clear_rvecs(fr->f_novirsum_n,fr->f_novirsum);
                }
                else
                {
                    clear_rvecs(homenr,fr->f_novirsum+start);
                }
                GMX_BARRIER(cr->mpi_comm_mygroup);
            }
            else
            {
                /* We are not calculating the pressure so we do not need
                 * a separate array for forces that do not contribute
                 * to the pressure.
                 */
                fr->f_novirsum = f;
            }
        }

        if (bSepLRF)
        {
            /* Add the long range forces to the short range forces */
            for(i=0; i<fr->natoms_force; i++)
            {
                copy_rvec(fr->f_twin[i],f[i]);
            }
        }
        else if (!(fr->bTwinRange && bNS))
        {
            /* Clear the short-range forces */
            clear_rvecs(fr->natoms_force,f);
        }

        clear_rvec(fr->vir_diag_posres);

        GMX_BARRIER(cr->mpi_comm_mygroup);
    }
    if (inputrec->ePull == epullCONSTRAINT)
    {
        clear_pull_forces(inputrec->pull);
    }

    /* update QMMMrec, if necessary */
    if(fr->bQMMM)
    {
        update_QMMMrec(cr,fr,x,mdatoms,box,top);
    }

    if ((flags & GMX_FORCE_BONDED) && top->idef.il[F_POSRES].nr > 0)
    {
        /* Position restraints always require full pbc */
        set_pbc(&pbc,inputrec->ePBC,box);
        v = posres(top->idef.il[F_POSRES].nr,top->idef.il[F_POSRES].iatoms,
                   top->idef.iparams_posres,
                   (const rvec*)x,fr->f_novirsum,fr->vir_diag_posres,
                   inputrec->ePBC==epbcNONE ? NULL : &pbc,lambda,&dvdl,
                   fr->rc_scaling,fr->ePBC,fr->posres_com,fr->posres_comB);
        if (bSepDVDL)
        {
            fprintf(fplog,sepdvdlformat,
                    interaction_function[F_POSRES].longname,v,dvdl);
        }
        enerd->term[F_POSRES] += v;
        /* This linear lambda dependence assumption is only correct
         * when only k depends on lambda,
         * not when the reference position depends on lambda.
         * grompp checks for this.
         */
        enerd->dvdl_lin += dvdl;
        inc_nrnb(nrnb,eNR_POSRES,top->idef.il[F_POSRES].nr/2);
    }

    /* Compute the bonded and non-bonded energies and optionally forces */    
    do_force_lowlevel(fplog,step,fr,inputrec,&(top->idef),
                      cr,nrnb,wcycle,mdatoms,&(inputrec->opts),
                      x,hist,f,enerd,fcd,mtop,top,fr->born,
                      &(top->atomtypes),bBornRadii,box,
                      lambda,graph,&(top->excls),fr->mu_tot,
                      flags,&cycles_pme);
    
    cycles_force = wallcycle_stop(wcycle,ewcFORCE);
    GMX_BARRIER(cr->mpi_comm_mygroup);
    
    if (ed)
    {
        do_flood(fplog,cr,x,f,ed,box,step);
    }
        
    if (DOMAINDECOMP(cr))
    {
        dd_force_flop_stop(cr->dd,nrnb);
        if (wcycle)
        {
            dd_cycles_add(cr->dd,cycles_force-cycles_pme,ddCyclF);
        }
    }
    
    if (bDoForces)
    {
        if (IR_ELEC_FIELD(*inputrec))
        {
            /* Compute forces due to electric field */
            calc_f_el(MASTER(cr) ? field : NULL,
                      start,homenr,mdatoms->chargeA,x,fr->f_novirsum,
                      inputrec->ex,inputrec->et,t);
        }
        
        /* Communicate the forces */
        if (PAR(cr))
        {
            wallcycle_start(wcycle,ewcMOVEF);
            if (DOMAINDECOMP(cr))
            {
                dd_move_f(cr->dd,f,fr->fshift);
                /* Do we need to communicate the separate force array
                 * for terms that do not contribute to the single sum virial?
                 * Position restraints and electric fields do not introduce
                 * inter-cg forces, only full electrostatics methods do.
                 * When we do not calculate the virial, fr->f_novirsum = f,
                 * so we have already communicated these forces.
                 */
                if (EEL_FULL(fr->eeltype) && cr->dd->n_intercg_excl &&
                    (flags & GMX_FORCE_VIRIAL))
                {
                    dd_move_f(cr->dd,fr->f_novirsum,NULL);
                }
                if (bSepLRF)
                {
                    /* We should not update the shift forces here,
                     * since f_twin is already included in f.
                     */
                    dd_move_f(cr->dd,fr->f_twin,NULL);
                }
            }
            else
            {
                pd_move_f(cr,f,nrnb);
                if (bSepLRF)
                {
                    pd_move_f(cr,fr->f_twin,nrnb);
                }
            }
            wallcycle_stop(wcycle,ewcMOVEF);
        }

        /* If we have NoVirSum forces, but we do not calculate the virial,
         * we sum fr->f_novirum=f later.
         */
        if (vsite && !(fr->bF_NoVirSum && !(flags & GMX_FORCE_VIRIAL)))
        {
            wallcycle_start(wcycle,ewcVSITESPREAD);
            spread_vsite_f(fplog,vsite,x,f,fr->fshift,nrnb,
                           &top->idef,fr->ePBC,fr->bMolPBC,graph,box,cr);
            wallcycle_stop(wcycle,ewcVSITESPREAD);

            if (bSepLRF)
            {
                wallcycle_start(wcycle,ewcVSITESPREAD);
                spread_vsite_f(fplog,vsite,x,fr->f_twin,NULL,
                               nrnb,
                               &top->idef,fr->ePBC,fr->bMolPBC,graph,box,cr);
                wallcycle_stop(wcycle,ewcVSITESPREAD);
            }
        }
        
        if (flags & GMX_FORCE_VIRIAL)
        {
            /* Calculation of the virial must be done after vsites! */
            calc_virial(fplog,mdatoms->start,mdatoms->homenr,x,f,
                        vir_force,graph,box,nrnb,fr,inputrec->ePBC);
        }
    }

    if (inputrec->ePull == epullUMBRELLA || inputrec->ePull == epullCONST_F)
    {
        /* Calculate the center of mass forces, this requires communication,
         * which is why pull_potential is called close to other communication.
         * The virial contribution is calculated directly,
         * which is why we call pull_potential after calc_virial.
         */
        set_pbc(&pbc,inputrec->ePBC,box);
        dvdl = 0; 
        enerd->term[F_COM_PULL] =
            pull_potential(inputrec->ePull,inputrec->pull,mdatoms,&pbc,
                           cr,t,lambda,x,f,vir_force,&dvdl);
        if (bSepDVDL)
        {
            fprintf(fplog,sepdvdlformat,"Com pull",enerd->term[F_COM_PULL],dvdl);
        }
        enerd->dvdl_lin += dvdl;
    }
    else
        enerd->term[F_COM_PULL] = 0.0;
    
    /* Add the forces from enforced rotation potentials (if any) */
    if (inputrec->bRot)
        enerd->term[F_COM_PULL] += add_rot_forces(inputrec->rot, f, cr,step,t);
    

    if (PAR(cr) && !(cr->duty & DUTY_PME))
    {
        cycles_ppdpme = wallcycle_stop(wcycle,ewcPPDURINGPME);
        dd_cycles_add(cr->dd,cycles_ppdpme,ddCyclPPduringPME);

        /* In case of node-splitting, the PP nodes receive the long-range 
         * forces, virial and energy from the PME nodes here.
         */    
        wallcycle_start(wcycle,ewcPP_PMEWAITRECVF);
        dvdl = 0;
        gmx_pme_receive_f(cr,fr->f_novirsum,fr->vir_el_recip,&e,&dvdl,
                          &cycles_seppme);
        if (bSepDVDL)
        {
            fprintf(fplog,sepdvdlformat,"PME mesh",e,dvdl);
        }
        enerd->term[F_COUL_RECIP] += e;
        enerd->dvdl_lin += dvdl;
        if (wcycle)
        {
            dd_cycles_add(cr->dd,cycles_seppme,ddCyclPME);
        }
        wallcycle_stop(wcycle,ewcPP_PMEWAITRECVF);
    }

    if (bDoForces && fr->bF_NoVirSum)
    {
        if (vsite)
        {
            /* Spread the mesh force on virtual sites to the other particles... 
             * This is parallellized. MPI communication is performed
             * if the constructing atoms aren't local.
             */
            wallcycle_start(wcycle,ewcVSITESPREAD);
            spread_vsite_f(fplog,vsite,x,fr->f_novirsum,NULL,nrnb,
                           &top->idef,fr->ePBC,fr->bMolPBC,graph,box,cr);
            wallcycle_stop(wcycle,ewcVSITESPREAD);
        }
        if (flags & GMX_FORCE_VIRIAL)
        {
            /* Now add the forces, this is local */
            if (fr->bDomDec)
            {
                sum_forces(0,fr->f_novirsum_n,f,fr->f_novirsum);
            }
            else
            {
                sum_forces(start,start+homenr,f,fr->f_novirsum);
            }
            if (EEL_FULL(fr->eeltype))
            {
                /* Add the mesh contribution to the virial */
                m_add(vir_force,fr->vir_el_recip,vir_force);
            }
            if (debug)
            {
                pr_rvecs(debug,0,"vir_force",vir_force,DIM);
            }
        }
    }
    
    /* Sum the potential energy terms from group contributions */
    sum_epot(&(inputrec->opts),enerd);
    
    if (fr->print_force >= 0 && bDoForces)
    {
        print_large_forces(stderr,mdatoms,cr,step,fr->print_force,x,f);
    }
}

void do_constrain_first(FILE *fplog,gmx_constr_t constr,
                        t_inputrec *inputrec,t_mdatoms *md,
                        t_state *state,
                        t_graph *graph,t_commrec *cr,t_nrnb *nrnb,
                        t_forcerec *fr,t_idef *idef)
{
    int    i,m,start,end;
    gmx_large_int_t step;
    double mass,tmass,vcm[4];
    real   dt=inputrec->delta_t;
    real   dvdlambda;
    rvec   *xcon;
    char   buf[22];
    
    start = md->start;
    end   = md->homenr + start;
    if (debug)
    {
        fprintf(debug,"vcm: start=%d, homenr=%d, end=%d\n",
                start,md->homenr,end);
    }
    snew(xcon,state->nalloc);

    /* Do a first constraining to reset particles... */
    step = inputrec->init_step;
    if (fplog)
    {
        fprintf(fplog,"\nConstraining the starting coordinates (step %s)\n",
                gmx_step_str(step,buf));
    }
    dvdlambda = 0;
    constrain(NULL,TRUE,FALSE,constr,idef,
              inputrec,cr,step,0,md,
              state->x,state->x,NULL,
              state->box,state->lambda,&dvdlambda,
              NULL,NULL,nrnb,econqCoord);
    
    if (EI_STATE_VELOCITY(inputrec->eI)) {
        for(i=start; (i<end); i++) {
            for(m=0; (m<DIM); m++) {
                /* Reverse the velocity */
                state->v[i][m] = -state->v[i][m];
                /* Store the position at t-dt in xcon */
                xcon[i][m] = state->x[i][m] + dt*state->v[i][m];
            }
        }
        
        /* Constrain the positions at t=-dt with the positions at t=0
         * as reference coordinates.
         */
        if (fplog)
        {
            fprintf(fplog,"\nConstraining the coordinates at t0-dt (step %s)\n",
                    gmx_step_str(step,buf));
        }
        dvdlambda = 0;
        constrain(NULL,TRUE,FALSE,constr,idef,
                  inputrec,cr,step,-1,md,
                  state->x,xcon,NULL,
                  state->box,state->lambda,&dvdlambda,
                  state->v,NULL,nrnb,econqCoord);
    
        sfree(xcon);

        for(m=0; (m<4); m++)
        {
            vcm[m] = 0;
        }
        for(i=start; i<end; i++)
        {
            mass = md->massT[i];
            for(m=0; m<DIM; m++)
            {
                /* Re-reverse the velocities */
                state->v[i][m] = -state->v[i][m];
                vcm[m] += state->v[i][m]*mass;
            }
            vcm[3] += mass;
        }
        
        if (inputrec->nstcomm != 0 || debug)
        {
            /* Compute the global sum of vcm */
            if (debug)
            {
                fprintf(debug,
                        "vcm: %8.3f  %8.3f  %8.3f,"
                        " total mass = %12.5e\n",
                        vcm[XX],vcm[YY],vcm[ZZ],vcm[3]);
            }
            if (PAR(cr))
            {
                gmx_sumd(4,vcm,cr);
            }
            tmass = vcm[3];
            for(m=0; (m<DIM); m++)
            {
                vcm[m] /= tmass;
            }
            if (debug)
            {
                fprintf(debug,"vcm: %8.3f  %8.3f  %8.3f,"
                        " total mass = %12.5e\n",vcm[XX],vcm[YY],vcm[ZZ],tmass);
            }
            if (inputrec->nstcomm != 0)
            {
                /* Now we have the velocity of center of mass,
                 * let's remove it.
                 */
                for(i=start; (i<end); i++)
                {
                    for(m=0; (m<DIM); m++)
                    {
                        state->v[i][m] -= vcm[m];
                    }
                }
            }
        }
    }
}

void calc_enervirdiff(FILE *fplog,int eDispCorr,t_forcerec *fr)
{
  double eners[2],virs[2],enersum,virsum,y0,f,g,h;
  double r0,r1,r,rc3,rc9,ea,eb,ec,pa,pb,pc,pd;
  double invscale,invscale2,invscale3;
  int    ri0,ri1,ri,i,offstart,offset;
  real   scale,*vdwtab; 

  fr->enershiftsix = 0;
  fr->enershifttwelve = 0;
  fr->enerdiffsix = 0;
  fr->enerdifftwelve = 0;
  fr->virdiffsix = 0;
  fr->virdifftwelve = 0;

  if (eDispCorr != edispcNO) {
    for(i=0; i<2; i++) {
      eners[i] = 0;
      virs[i]  = 0;
    }
    if ((fr->vdwtype == evdwSWITCH) || (fr->vdwtype == evdwSHIFT)) {
      if (fr->rvdw_switch == 0)
        gmx_fatal(FARGS,
                  "With dispersion correction rvdw-switch can not be zero "
                  "for vdw-type = %s",evdw_names[fr->vdwtype]);

      scale  = fr->nblists[0].tab.scale;
      vdwtab = fr->nblists[0].vdwtab;

      /* Round the cut-offs to exact table values for precision */
      ri0 = floor(fr->rvdw_switch*scale);
      ri1 = ceil(fr->rvdw*scale);
      r0  = ri0/scale;
      r1  = ri1/scale;
      rc3 = r0*r0*r0;
      rc9  = rc3*rc3*rc3;

      if (fr->vdwtype == evdwSHIFT) {
        /* Determine the constant energy shift below rvdw_switch */
        fr->enershiftsix    = (real)(-1.0/(rc3*rc3)) - vdwtab[8*ri0];
        fr->enershifttwelve = (real)( 1.0/(rc9*rc3)) - vdwtab[8*ri0 + 4];
      }
      /* Add the constant part from 0 to rvdw_switch.
       * This integration from 0 to rvdw_switch overcounts the number
       * of interactions by 1, as it also counts the self interaction.
       * We will correct for this later.
       */
      eners[0] += 4.0*M_PI*fr->enershiftsix*rc3/3.0;
      eners[1] += 4.0*M_PI*fr->enershifttwelve*rc3/3.0;
      
      invscale = 1.0/(scale);  
      invscale2 = invscale*invscale;
      invscale3 = invscale*invscale2;

      /* following summation derived from cubic spline definition,
        Numerical Recipies in C, second edition, p. 113-116.  Exact
        for the cubic spline.  We first calculate the negative of
        the energy from rvdw to rvdw_switch, assuming that g(r)=1,
        and then add the more standard, abrupt cutoff correction to
        that result, yielding the long-range correction for a
        switched function.  We perform both the pressure and energy
        loops at the same time for simplicity, as the computational
        cost is low. */
      
      for (i=0;i<2;i++) {
        enersum = 0.0; virsum = 0.0;
        if (i==0)
          offstart = 0;
        else
          offstart = 4;
        for (ri=ri0; ri<ri1; ri++) {
          r = ri*invscale;
          ea = invscale3;
          eb = 2.0*invscale2*r;
          ec = invscale*r*r;
          
          pa = invscale3;
          pb = 3.0*invscale2*r;
          pc = 3.0*invscale*r*r;
          pd = r*r*r;
          
          /* this "8" is from the packing in the vdwtab array - perhaps
            should be #define'ed? */
          offset = 8*ri + offstart;
          y0 = vdwtab[offset];
          f = vdwtab[offset+1];
          g = vdwtab[offset+2];
          h = vdwtab[offset+3];
          
          enersum += y0*(ea/3 + eb/2 + ec) + f*(ea/4 + eb/3 + ec/2)+
            g*(ea/5 + eb/4 + ec/3) + h*(ea/6 + eb/5 + ec/4);  
          virsum  +=  f*(pa/4 + pb/3 + pc/2 + pd) + 
            2*g*(pa/5 + pb/4 + pc/3 + pd/2) + 3*h*(pa/6 + pb/5 + pc/4 + pd/3);
          
        }
        enersum *= 4.0*M_PI;
        virsum  *= 4.0*M_PI; 
        eners[i] -= enersum;
        virs[i]  -= virsum;
      }

      /* now add the correction for rvdw_switch to infinity */
      eners[0] += -4.0*M_PI/(3.0*rc3);
      eners[1] +=  4.0*M_PI/(9.0*rc9);
      virs[0]  +=  8.0*M_PI/rc3;
      virs[1]  += -16.0*M_PI/(3.0*rc9);
    } 
    else if ((fr->vdwtype == evdwCUT) || (fr->vdwtype == evdwUSER)) {
      if (fr->vdwtype == evdwUSER && fplog)
        fprintf(fplog,
                "WARNING: using dispersion correction with user tables\n");
      rc3  = fr->rvdw*fr->rvdw*fr->rvdw;
      rc9  = rc3*rc3*rc3;
      eners[0] += -4.0*M_PI/(3.0*rc3);
      eners[1] +=  4.0*M_PI/(9.0*rc9);
      virs[0]  +=  8.0*M_PI/rc3;
      virs[1]  += -16.0*M_PI/(3.0*rc9);
    } else {
      gmx_fatal(FARGS,
                "Dispersion correction is not implemented for vdw-type = %s",
                evdw_names[fr->vdwtype]);
    }
    fr->enerdiffsix    = eners[0];
    fr->enerdifftwelve = eners[1];
    /* The 0.5 is due to the Gromacs definition of the virial */
    fr->virdiffsix     = 0.5*virs[0];
    fr->virdifftwelve  = 0.5*virs[1];
  }
}

void calc_dispcorr(FILE *fplog,t_inputrec *ir,t_forcerec *fr,
                   gmx_large_int_t step,int natoms,matrix box,real lambda,
                   tensor pres,tensor virial,gmx_enerdata_t *enerd)
{
    bool bCorrAll,bCorrPres;
    real dvdlambda,invvol,dens,ninter,avcsix,avctwelve,enerdiff,svir=0,spres=0;
    int  m;
    
    enerd->term[F_DISPCORR] = 0.0;
    enerd->term[F_PDISPCORR] = 0.0;
    
    if (ir->eDispCorr != edispcNO)
    {
        bCorrAll  = (ir->eDispCorr == edispcAllEner ||
                     ir->eDispCorr == edispcAllEnerPres);
        bCorrPres = (ir->eDispCorr == edispcEnerPres ||
                     ir->eDispCorr == edispcAllEnerPres);
        
        invvol = 1/det(box);
        if (fr->n_tpi)
        {
            /* Only correct for the interactions with the inserted molecule */
            dens = (natoms - fr->n_tpi)*invvol;
            ninter = fr->n_tpi;
        }
        else
        {
            dens = natoms*invvol;
            ninter = 0.5*natoms;
        }
        
        if (ir->efep == efepNO)
        {
            avcsix    = fr->avcsix[0];
            avctwelve = fr->avctwelve[0];
        }
        else
        {
            avcsix    = (1 - lambda)*fr->avcsix[0]    + lambda*fr->avcsix[1];
            avctwelve = (1 - lambda)*fr->avctwelve[0] + lambda*fr->avctwelve[1];
        }
    
        enerdiff = ninter*(dens*fr->enerdiffsix - fr->enershiftsix);
        enerd->term[F_DISPCORR] += avcsix*enerdiff;
        dvdlambda = 0.0;
        if (ir->efep != efepNO)
        {
            dvdlambda += (fr->avcsix[1] - fr->avcsix[0])*enerdiff;
        }
        
        if (bCorrAll)
        {
            enerdiff = ninter*(dens*fr->enerdifftwelve - fr->enershifttwelve);
            enerd->term[F_DISPCORR] += avctwelve*enerdiff;
            if (fr->efep != efepNO)
            {
                dvdlambda += (fr->avctwelve[1] - fr->avctwelve[0])*enerdiff;
            }
        }
        
        if (bCorrPres)
        {
            svir = ninter*dens*avcsix*fr->virdiffsix/3.0;
            if (ir->eDispCorr == edispcAllEnerPres)
            {
                svir += ninter*dens*avctwelve*fr->virdifftwelve/3.0;
            }
            /* The factor 2 is because of the Gromacs virial definition */
            spres = -2.0*invvol*svir*PRESFAC;
            
            for(m=0; m<DIM; m++) {
                virial[m][m] += svir;
                pres[m][m] += spres;
            }
            enerd->term[F_PDISPCORR] = spres;
            enerd->term[F_PRES]     += spres;
        }
        
        if (fr->bSepDVDL && do_per_step(step,ir->nstlog))
        {
            fprintf(fplog,sepdvdlformat,"Dispersion correction",
                    enerd->term[F_DISPCORR],dvdlambda);
        }
        
        enerd->term[F_EPOT] += enerd->term[F_DISPCORR];
        if (fr->efep != efepNO)
        {
            enerd->dvdl_lin += dvdlambda;
        }
    }
}


void do_pbc_first(FILE *fplog,matrix box,t_forcerec *fr,
                  t_graph *graph,rvec x[])
{
  if (fplog)
    fprintf(fplog,"Removing pbc first time\n");
  calc_shifts(box,fr->shift_vec);
  if (graph) {
    mk_mshift(fplog,graph,fr->ePBC,box,x);
    if (gmx_debug_at)
      p_graph(debug,"do_pbc_first 1",graph);
    shift_self(graph,box,x);
    /* By doing an extra mk_mshift the molecules that are broken
     * because they were e.g. imported from another software
     * will be made whole again. Such are the healing powers
     * of GROMACS.
     */
    mk_mshift(fplog,graph,fr->ePBC,box,x);
    if (gmx_debug_at)
      p_graph(debug,"do_pbc_first 2",graph);
  }
  if (fplog)
    fprintf(fplog,"Done rmpbc\n");
}

static void low_do_pbc_mtop(FILE *fplog,int ePBC,matrix box,
                            gmx_mtop_t *mtop,rvec x[],
                            bool bFirst)
{
  t_graph *graph;
  int mb,as,mol;
  gmx_molblock_t *molb;

  if (bFirst && fplog)
    fprintf(fplog,"Removing pbc first time\n");

  snew(graph,1);
  as = 0;
  for(mb=0; mb<mtop->nmolblock; mb++) {
    molb = &mtop->molblock[mb];
    if (molb->natoms_mol == 1 || 
        (!bFirst && mtop->moltype[molb->type].cgs.nr == 1)) {
      /* Just one atom or charge group in the molecule, no PBC required */
      as += molb->nmol*molb->natoms_mol;
    } else {
      /* Pass NULL iso fplog to avoid graph prints for each molecule type */
      mk_graph_ilist(NULL,mtop->moltype[molb->type].ilist,
                     0,molb->natoms_mol,FALSE,FALSE,graph);
      
      for(mol=0; mol<molb->nmol; mol++) {
        mk_mshift(fplog,graph,ePBC,box,x+as);
        
        shift_self(graph,box,x+as);
        /* The molecule is whole now.
         * We don't need the second mk_mshift call as in do_pbc_first,
         * since we no longer need this graph.
         */
        
        as += molb->natoms_mol;
      }
      done_graph(graph);
    }
  }
  sfree(graph);
}

void do_pbc_first_mtop(FILE *fplog,int ePBC,matrix box,
                       gmx_mtop_t *mtop,rvec x[])
{
  low_do_pbc_mtop(fplog,ePBC,box,mtop,x,TRUE);
}

void do_pbc_mtop(FILE *fplog,int ePBC,matrix box,
                 gmx_mtop_t *mtop,rvec x[])
{
  low_do_pbc_mtop(fplog,ePBC,box,mtop,x,FALSE);
}

void finish_run(FILE *fplog,t_commrec *cr,const char *confout,
                t_inputrec *inputrec,
                t_nrnb nrnb[],gmx_wallcycle_t wcycle,
                gmx_runtime_t *runtime,
                bool bWriteStat)
{
  int    i,j;
  t_nrnb *nrnb_tot=NULL;
  real   delta_t;
  double nbfs,mflop;
  double cycles[ewcNR];

  wallcycle_sum(cr,wcycle,cycles);

  if (cr->nnodes > 1) {
    if (SIMMASTER(cr))
      snew(nrnb_tot,1);
#ifdef GMX_MPI
    MPI_Reduce(nrnb->n,nrnb_tot->n,eNRNB,MPI_DOUBLE,MPI_SUM,
               MASTERRANK(cr),cr->mpi_comm_mysim);
#endif  
  } else {
    nrnb_tot = nrnb;
  }
    
  if (SIMMASTER(cr)) {
    print_flop(fplog,nrnb_tot,&nbfs,&mflop);
    if (cr->nnodes > 1) {
      sfree(nrnb_tot);
    }
  }

  if ((cr->duty & DUTY_PP) && DOMAINDECOMP(cr)) {
    print_dd_statistics(cr,inputrec,fplog);
  }

  if (SIMMASTER(cr)) {
    if (PARTDECOMP(cr)) {
      pr_load(fplog,cr,nrnb_tot);
    }

    wallcycle_print(fplog,cr->nnodes,cr->npmenodes,runtime->realtime,
                    wcycle,cycles);

    if (EI_DYNAMICS(inputrec->eI)) {
      delta_t = inputrec->delta_t;
    } else {
      delta_t = 0;
    }
    
    if (fplog) {
        print_perf(fplog,runtime->proctime,runtime->realtime,
                   cr->nnodes-cr->npmenodes,
                   runtime->nsteps_done,delta_t,nbfs,mflop);
    }
    if (bWriteStat) {
        print_perf(stderr,runtime->proctime,runtime->realtime,
                   cr->nnodes-cr->npmenodes,
                   runtime->nsteps_done,delta_t,nbfs,mflop);
    }

    /*
    runtime=inputrec->nsteps*inputrec->delta_t;
    if (bWriteStat) {
      if (cr->nnodes == 1)
        fprintf(stderr,"\n\n");
      print_perf(stderr,nodetime,realtime,runtime,&ntot,
                 cr->nnodes-cr->npmenodes,FALSE);
    }
    wallcycle_print(fplog,cr->nnodes,cr->npmenodes,realtime,wcycle,cycles);
    print_perf(fplog,nodetime,realtime,runtime,&ntot,cr->nnodes-cr->npmenodes,
               TRUE);
    if (PARTDECOMP(cr))
      pr_load(fplog,cr,nrnb_all);
    if (cr->nnodes > 1)
      sfree(nrnb_all);
    */
  }
}

void init_md(FILE *fplog,
             t_commrec *cr,t_inputrec *ir,const output_env_t oenv,
             double *t,double *t0,
             real *lambda,double *lam0,
             t_nrnb *nrnb,gmx_mtop_t *mtop,
             gmx_update_t *upd,
             int nfile,const t_filenm fnm[],
             int *fp_trn,int *fp_xtc,ener_file_t *fp_ene,const char **fn_cpt,
             FILE **fp_dhdl,FILE **fp_field,
             t_mdebin **mdebin,
             tensor force_vir,tensor shake_vir,rvec mu_tot,
             bool *bNEMD,bool *bSimAnn,t_vcm **vcm, unsigned long Flags)
{
    int  i,j,n;
    real tmpt,mod;
    char filemode[2];
    
    sprintf(filemode, (Flags & MD_APPENDFILES) ? "a" : "w");
        
    /* Initial values */
    *t = *t0       = ir->init_t;
    if (ir->efep != efepNO)
    {
        *lam0 = ir->init_lambda;
        *lambda = *lam0 + ir->init_step*ir->delta_lambda;
    }
    else
    {
        *lambda = *lam0   = 0.0;
    } 
    
    *bSimAnn=FALSE;
    for(i=0;i<ir->opts.ngtc;i++)
    {
        /* set bSimAnn if any group is being annealed */
        if(ir->opts.annealing[i]!=eannNO)
        {
            *bSimAnn = TRUE;
        }
    }
    if (*bSimAnn)
    {
        update_annealing_target_temp(&(ir->opts),ir->init_t);
    }
    
    *bNEMD = (ir->opts.ngacc > 1) || (norm(ir->opts.acc[0]) > 0);
    
    if (upd)
    {
        *upd = init_update(fplog,ir);
    }
    
    if (vcm != NULL)
    {
        *vcm = init_vcm(fplog,&mtop->groups,ir);
    }
    
    if (EI_DYNAMICS(ir->eI) && !(Flags & MD_APPENDFILES))
    {
        if (ir->etc == etcBERENDSEN)
        {
            please_cite(fplog,"Berendsen84a");
        }
        if (ir->etc == etcVRESCALE)
        {
            please_cite(fplog,"Bussi2007a");
        }
    }
    
    init_nrnb(nrnb);
    
    if (nfile != -1)
    {
        *fp_trn = -1;
        *fp_ene = NULL;
        *fp_xtc = -1;
        
        if (MASTER(cr)) 
        {
            *fp_trn = open_trn(ftp2fn(efTRN,nfile,fnm), filemode);
            if (ir->nstxtcout > 0)
            {
                *fp_xtc = open_xtc(ftp2fn(efXTC,nfile,fnm), filemode);
            }
            *fp_ene = open_enx(ftp2fn(efEDR,nfile,fnm), filemode);
            *fn_cpt = opt2fn("-cpo",nfile,fnm);
            
            if ((fp_dhdl != NULL) && ir->efep != efepNO && ir->nstdhdl > 0)
            {
                if(Flags & MD_APPENDFILES)
                {
                    *fp_dhdl= gmx_fio_fopen(opt2fn("-dhdl",nfile,fnm),filemode);
                }
                else
                {
                    *fp_dhdl = open_dhdl(opt2fn("-dhdl",nfile,fnm),ir,oenv);
                }
            }
            
            if ((fp_field != NULL) &&
                (ir->ex[XX].n || ir->ex[YY].n ||ir->ex[ZZ].n))
            {
                if(Flags & MD_APPENDFILES)
                {
                    *fp_dhdl=gmx_fio_fopen(opt2fn("-field",nfile,fnm),filemode);
                }
                else
                {                                 
                    *fp_field = xvgropen(opt2fn("-field",nfile,fnm),
                                         "Applied electric field","Time (ps)",
                                         "E (V/nm)",oenv);
                }
            }
        }
        *mdebin = init_mdebin( (Flags & MD_APPENDFILES) ? NULL : *fp_ene,
                                mtop,ir);
    }
    
    /* Initiate variables */  
    clear_mat(force_vir);
    clear_mat(shake_vir);
    clear_rvec(mu_tot);
    
    debug_gmx();
}