Resolving the issues with restoring vesicles from vtu and fixing the volume...

Samo Penic

2018-06-27 6da644f98434d3eac8b4e19981754f6030a315a5

 src/vertexmove.c

@@ -1,3 +1,4 @@
/* vim: set ts=4 sts=4 sw=4 noet : */
#include<stdlib.h>
#include<math.h>
#include "general.h"
@@ -9,79 +10,224 @@
#include "timestep.h"
#include "cell.h"
//#include "io.h"
#include "io.h"
#include<stdio.h>
#include "vertexmove.h"
#include <string.h>
#include "constvol.h"

ts_bool single_verticle_timestep(ts_vesicle *vesicle,ts_vertex *vtx,ts_double
*rn){
ts_bool single_verticle_timestep(ts_vesicle *vesicle,ts_vertex *vtx,ts_double *rn){
    ts_uint i;
    ts_double dist;
    ts_bool retval; 
    ts_uint cellidx; 
    ts_double xold,yold,zold;
    ts_double delta_energy,oenergy;
    ts_vertex *ovtx;
    ts_vertex *tvtx=(ts_vertex *)calloc(1,sizeof(ts_vertex));
    ts_double delta_energy, delta_energy_cv,oenergy,dvol=0.0, darea=0.0, dstretchenergy=0.0;
    ts_double temp_area=0.0; //for stretching
    ts_double costheta,sintheta,phi,r;
   //This will hold all the information of vtx and its neighbours
   ts_vertex backupvtx[20], *constvol_vtx_moved=NULL, *constvol_vtx_backup=NULL;
   memcpy((void *)&backupvtx[0],(void *)vtx,sizeof(ts_vertex));

    //randomly we move the temporary vertex
//    tvtx->x=vtx->x+vesicle->stepsize*(2.0*rn[0]-1.0);
//    tvtx->y=vtx->y+vesicle->stepsize*(2.0*rn[1]-1.0);
//    tvtx->z=vtx->z+vesicle->stepsize*(2.0*rn[2]-1.0);
   //random move in a sphere with radius stepsize:
   //Some stupid tests for debugging cell occupation!
/*        cellidx=vertex_self_avoidance(vesicle, vtx);
   if(vesicle->clist->cell[cellidx]==vtx->cell){
      fprintf(stderr,"Idx match!\n");
   } else {
      fprintf(stderr,"***** Idx don't match!\n");
      fatal("ENding.",1);
   }
*/

       //temporarly moving the vertex
//   vtx->x=vtx->x+vesicle->stepsize*(2.0*rn[0]-1.0);
//       vtx->y=vtx->y+vesicle->stepsize*(2.0*rn[1]-1.0);
//       vtx->z=vtx->z+vesicle->stepsize*(2.0*rn[2]-1.0);

//random move in a sphere with radius stepsize:
   r=vesicle->stepsize*rn[0];
   phi=rn[1]*2*M_PI;
   costheta=2*rn[2]-1;
   sintheta=sqrt(1-pow(costheta,2));
   tvtx->x=vtx->x+r*sintheta*cos(phi);
   tvtx->y=vtx->y+r*sintheta*sin(phi);
   tvtx->z=vtx->z+r*costheta;
    //check we if some length to neighbours are too much
   vtx->x=vtx->x+r*sintheta*cos(phi);
   vtx->y=vtx->y+r*sintheta*sin(phi);
   vtx->z=vtx->z+r*costheta;


//distance with neighbours check
    for(i=0;i<vtx->neigh_no;i++){
        dist=vtx_distance_sq(tvtx,vtx->neigh[i]);
        dist=vtx_distance_sq(vtx,vtx->neigh[i]);
        if(dist<1.0 || dist>vesicle->dmax) {
      vtx_free(tvtx);
//   fprintf(stderr,"Fail 1, dist=%f, vesicle->dmax=%f\n", dist, vesicle->dmax);
      return TS_FAIL;
          vtx=memcpy((void *)vtx,(void *)&backupvtx[0],sizeof(ts_vertex));
          return TS_FAIL;
      }
    }
    //self avoidance check with distant vertices
     cellidx=vertex_self_avoidance(vesicle, tvtx);
    //check occupation number
     retval=cell_occupation_number_and_internal_proximity(vesicle->clist,cellidx,vtx,tvtx);

// Distance with grafted poly-vertex check:	
   if(vtx->grafted_poly!=NULL){
      dist=vtx_distance_sq(vtx,vtx->grafted_poly->vlist->vtx[0]);
        if(dist<1.0 || dist>vesicle->dmax) {
      vtx=memcpy((void *)vtx,(void *)&backupvtx[0],sizeof(ts_vertex));
      return TS_FAIL;
      }
   }

// TODO: Maybe faster if checks only nucleus-neighboring cells
// Nucleus penetration check:
//#define SQ(x) x*x
if(vesicle->R_nucleus>0.0){
   if ((vtx->x-vesicle->nucleus_center[0])*(vtx->x-vesicle->nucleus_center[0])+ (vtx->y-vesicle->nucleus_center[1])*(vtx->y-vesicle->nucleus_center[1]) + (vtx->z-vesicle->nucleus_center[2])*(vtx->z-vesicle->nucleus_center[2]) < vesicle->R_nucleus){
      vtx=memcpy((void *)vtx,(void *)&backupvtx[0],sizeof(ts_vertex));
      return TS_FAIL;
   }
} else if(vesicle->R_nucleusX>0.0){
//   fprintf(stderr,"DEBUG, (Rx, Ry,Rz)^2=(%f,%f,%f)\n",vesicle->R_nucleusX, vesicle->R_nucleusY, vesicle->R_nucleusZ);
//   if (SQ(vtx->x-vesicle->nucleus_center[0])/vesicle->R_nucleusX + SQ(vtx->y-vesicle->nucleus_center[1])/vesicle->R_nucleusY + SQ(vtx->z-vesicle->nucleus_center[2])/vesicle->R_nucleusZ < 1.0){
   if ((vtx->x-vesicle->nucleus_center[0])*(vtx->x-vesicle->nucleus_center[0])/vesicle->R_nucleusX + (vtx->y-vesicle->nucleus_center[1])*(vtx->y-vesicle->nucleus_center[1])/vesicle->R_nucleusY + (vtx->z-vesicle->nucleus_center[2])*(vtx->z-vesicle->nucleus_center[2])/vesicle->R_nucleusZ < 1.0){
//   if (SQ(vtx->x)/vesicle->R_nucleusX + SQ(vtx->y)/vesicle->R_nucleusY + SQ(vtx->z)/vesicle->R_nucleusZ < 1.0){
      vtx=memcpy((void *)vtx,(void *)&backupvtx[0],sizeof(ts_vertex));
      return TS_FAIL;
   }

}
//#undef SQ
//self avoidance check with distant vertices
   cellidx=vertex_self_avoidance(vesicle, vtx);
   //check occupation number
   retval=cell_occupation_number_and_internal_proximity(vesicle->clist,cellidx,vtx);

    if(retval==TS_FAIL){
   vtx_free(tvtx);
//   fprintf(stderr,"Fail 2\n");
      vtx=memcpy((void *)vtx,(void *)&backupvtx[0],sizeof(ts_vertex));
        return TS_FAIL;
    } 
    
    //if all the tests are successful, then we update the vertex position
    xold=vtx->x;
    yold=vtx->y;
    zold=vtx->z;
    ovtx=malloc(sizeof(ts_vertex));
    vtx_copy(ovtx,vtx);
    vtx->x=tvtx->x;
    vtx->y=tvtx->y;
    vtx->z=tvtx->z;
   
 
//if all the tests are successful, then energy for vtx and neighbours is calculated
   for(i=0;i<vtx->neigh_no;i++){
   memcpy((void *)&backupvtx[i+1],(void *)vtx->neigh[i],sizeof(ts_vertex));
   }

   if(vesicle->pswitch == 1 || vesicle->tape->constvolswitch>0){
      for(i=0;i<vtx->tristar_no;i++) dvol-=vtx->tristar[i]->volume;
   }

    if(vesicle->tape->constareaswitch==2){
      for(i=0;i<vtx->tristar_no;i++) darea-=vtx->tristar[i]->area;
    
    }
   //stretching energy 1 of 3
   if(vesicle->tape->stretchswitch==1){
      temp_area=vesicle->area;
      dstretchenergy-=stretchenergy2(vesicle->area,vesicle->tlist->a0*vesicle->tlist->n);
      for(i=0;i<vtx->tristar_no;i++){
         temp_area-=vtx->tristar[i]->area;
      }
      //0.5*vesicle->tape->xkA0*pow((vesicle->area-vesicle->tlist->a0*vesicle->tlist->n),2)/(vesicle->tlist->a0*vesicle->tlist->n);
      //for(i=0;i<vtx->tristar_no;i++) dstretchenergy-=vtx->tristar[i]->energy;
   }
    delta_energy=0;
    
//    vesicle_volume(vesicle);
//    fprintf(stderr,"Volume in the beginning=%1.16e\n", vesicle->volume);

    //update the normals of triangles that share bead i.
    for(i=0;i<vtx->tristar_no;i++) triangle_normal_vector(vtx->tristar[i]);
    //energy and curvature
   oenergy=vtx->energy;
    energy_vertex(vtx);
    delta_energy=vtx->xk*(vtx->energy - ovtx->energy);
    delta_energy=vtx->xk*(vtx->energy - oenergy);
    //the same is done for neighbouring vertices
    for(i=0;i<vtx->neigh_no;i++){
        oenergy=vtx->neigh[i]->energy;
        energy_vertex(vtx->neigh[i]);
        delta_energy+=vtx->neigh[i]->xk*(vtx->neigh[i]->energy-oenergy);
    }

   if(vesicle->pswitch == 1 || vesicle->tape->constvolswitch >0){
      for(i=0;i<vtx->tristar_no;i++) dvol+=vtx->tristar[i]->volume;
        if(vesicle->pswitch==1) delta_energy-=vesicle->pressure*dvol;
   };

    if(vesicle->tape->constareaswitch==2){
        /* check whether the darea is gt epsarea */
      for(i=0;i<vtx->tristar_no;i++) darea+=vtx->tristar[i]->area;
        if(fabs(vesicle->area+darea-A0)>epsarea){
           //restore old state.
          vtx=memcpy((void *)vtx,(void *)&backupvtx[0],sizeof(ts_vertex));
              for(i=0;i<vtx->neigh_no;i++){
                 vtx->neigh[i]=memcpy((void *)vtx->neigh[i],(void *)&backupvtx[i+1],sizeof(ts_vertex));
              }
                  for(i=0;i<vtx->tristar_no;i++) triangle_normal_vector(vtx->tristar[i]); 
                  //fprintf(stderr,"fajlam!\n");
                  return TS_FAIL;
      }


    }

   if(vesicle->tape->constvolswitch==2){
      /*check whether the dvol is gt than epsvol */
         //fprintf(stderr,"DVOL=%1.16e, V0=%1.16e, vesicleVolume=%1.16e, |volume+dvol-V0|=%1.16e\n",dvol, V0, vesicle->volume, fabs(vesicle->volume+dvol-V0));
      if(fabs(vesicle->volume+dvol-V0)>epsvol){
         //restore old state.
          vtx=memcpy((void *)vtx,(void *)&backupvtx[0],sizeof(ts_vertex));
              for(i=0;i<vtx->neigh_no;i++){
                 vtx->neigh[i]=memcpy((void *)vtx->neigh[i],(void *)&backupvtx[i+1],sizeof(ts_vertex));
              }
                  for(i=0;i<vtx->tristar_no;i++) triangle_normal_vector(vtx->tristar[i]); 
               //   fprintf(stderr,"fajlam!\n");
                  return TS_FAIL;
      }

   } else
      //fprintf(stderr, "success\n");
//    vesicle_volume(vesicle);
//    fprintf(stderr,"Volume before=%1.16e\n", vesicle->volume);
   if(vesicle->tape->constvolswitch == 1){
        retval=constvolume(vesicle, vtx, -dvol, &delta_energy_cv, &constvol_vtx_moved,&constvol_vtx_backup);
        if(retval==TS_FAIL){ // if we couldn't move the vertex to assure constant volume
            vtx=memcpy((void *)vtx,(void *)&backupvtx[0],sizeof(ts_vertex));
           for(i=0;i<vtx->neigh_no;i++){
              vtx->neigh[i]=memcpy((void *)vtx->neigh[i],(void *)&backupvtx[i+1],sizeof(ts_vertex));
           }
            for(i=0;i<vtx->tristar_no;i++) triangle_normal_vector(vtx->tristar[i]); 
 //           fprintf(stderr,"fajlam!\n");
            return TS_FAIL;
        }
//    vesicle_volume(vesicle);
//    fprintf(stderr,"Volume after=%1.16e\n", vesicle->volume);
//    fprintf(stderr,"Volume after-dvol=%1.16e\n", vesicle->volume-dvol);
//    fprintf(stderr,"Denergy before=%e\n",delta_energy);
    
    delta_energy+=delta_energy_cv;
//    fprintf(stderr,"Denergy after=%e\n",delta_energy);
    }
/* Vertices with spontaneous curvature may have spontaneous force perpendicular to the surface of the vesicle. additional delta energy is calculated in this function */
   delta_energy+=direct_force_energy(vesicle,vtx,backupvtx);

   //stretching energy 2 of 3
   if(vesicle->tape->stretchswitch==1){
      for(i=0;i<vtx->tristar_no;i++){
         temp_area+=vtx->tristar[i]->area; 
         }
      dstretchenergy+=stretchenergy2(temp_area,vesicle->tlist->a0*vesicle->tlist->n);
      dstretchenergy=0.5*vesicle->tape->xkA0*dstretchenergy;
		
   }

   delta_energy+=dstretchenergy;	
		
/* No poly-bond energy for now!
   if(vtx->grafted_poly!=NULL){
      delta_energy+=
         (pow(sqrt(vtx_distance_sq(vtx, vtx->grafted_poly->vlist->vtx[0])-1),2)-
         pow(sqrt(vtx_distance_sq(&backupvtx[0], vtx->grafted_poly->vlist->vtx[0])-1),2)) *vtx->grafted_poly->k;
   }
*/
//   fprintf(stderr, "DE=%f\n",delta_energy);
    //MONTE CARLOOOOOOOO
//   if(vtx->c!=0.0) printf("DE=%f\n",delta_energy);
    if(delta_energy>=0){
#ifdef TS_DOUBLE_DOUBLE
        if(exp(-delta_energy)< drand48() )
        if(exp(-delta_energy)< drand48())
#endif
#ifdef TS_DOUBLE_FLOAT
        if(expf(-delta_energy)< (ts_float)drand48())
@@ -91,30 +237,282 @@
#endif
    {
    //not accepted, reverting changes
    vtx->x=xold;
    vtx->y=yold;
    vtx->z=zold;
  //  fprintf(stderr,"MC failed\n");
   vtx=memcpy((void *)vtx,(void *)&backupvtx[0],sizeof(ts_vertex));
   for(i=0;i<vtx->neigh_no;i++){
      vtx->neigh[i]=memcpy((void *)vtx->neigh[i],(void *)&backupvtx[i+1],sizeof(ts_vertex));
   }
	
    //update the normals of triangles that share bead i.
    for(i=0;i<vtx->tristar_no;i++) triangle_normal_vector(vtx->tristar[i]);
    //energy and curvature
    energy_vertex(vtx);
    //the same is done for neighbouring vertices
   for(i=0;i<vtx->neigh_no;i++) energy_vertex(vtx->neigh[i]);
   free(ovtx->bond_length);
    free(ovtx->bond_length_dual);
    free(ovtx);
    vtx_free(tvtx);
   for(i=0;i<vtx->tristar_no;i++) triangle_normal_vector(vtx->tristar[i]);
/*   //stretching energy 3 of 3
   if(vesicle->tape->stretchswitch==1){
      for(i=0;i<vtx->tristar_no;i++){ 
         stretchenergy(vesicle,vtx->tristar[i]);
         }
   }
*/
//    fprintf(stderr, "before vtx(x,y,z)=%e,%e,%e\n",constvol_vtx_moved->x, constvol_vtx_moved->y, constvol_vtx_moved->z);
    if(vesicle->tape->constvolswitch == 1){
        constvolumerestore(constvol_vtx_moved,constvol_vtx_backup);
    }
//    fprintf(stderr, "after vtx(x,y,z)=%e,%e,%e\n",constvol_vtx_moved->x, constvol_vtx_moved->y, constvol_vtx_moved->z);
//    vesicle_volume(vesicle);
//    fprintf(stderr,"Volume after fail=%1.16e\n", vesicle->volume);
    return TS_FAIL; 
    }
}
    //END MONTE CARLOOOOOOO
   //accepted	
 //   fprintf(stderr,"MC accepted\n");
//   oldcellidx=vertex_self_avoidance(vesicle, &backupvtx[0]);
   if(vtx->cell!=vesicle->clist->cell[cellidx]){
      retval=cell_add_vertex(vesicle->clist->cell[cellidx],vtx);
//      if(retval==TS_SUCCESS) cell_remove_vertex(vesicle->clist->cell[oldcellidx],vtx);
      if(retval==TS_SUCCESS) cell_remove_vertex(backupvtx[0].cell,vtx);
		
   }

    //TODO: change cell occupation if necessary!
//   fprintf(stderr,"Success!!\n");
    free(ovtx->bond_length);
    free(ovtx->bond_length_dual);
    free(ovtx);
    vtx_free(tvtx);
    if(vesicle->tape->constvolswitch == 2){
   vesicle->volume+=dvol;
    } else
    if(vesicle->tape->constvolswitch == 1){
        constvolumeaccept(vesicle,constvol_vtx_moved,constvol_vtx_backup);
    }

    if(vesicle->tape->constareaswitch==2){
        vesicle->area+=darea;
    }
   //stretching energy 3 of 3
   if(vesicle->tape->stretchswitch==1){
      vesicle->area=temp_area;
   }
//   if(oldcellidx);
    //END MONTE CARLOOOOOOO
//    vesicle_volume(vesicle);
//    fprintf(stderr,"Volume after success=%1.16e\n", vesicle->volume);
    return TS_SUCCESS;
}


ts_bool single_poly_vertex_move(ts_vesicle *vesicle,ts_poly *poly,ts_vertex *vtx,ts_double *rn){
   ts_uint i;
   ts_bool retval; 
   ts_uint cellidx; 
//   ts_double delta_energy;
   ts_double costheta,sintheta,phi,r;
   ts_double dist;
   //This will hold all the information of vtx and its neighbours
   ts_vertex backupvtx;
//   ts_bond backupbond[2];
   memcpy((void *)&backupvtx,(void *)vtx,sizeof(ts_vertex));

   //random move in a sphere with radius stepsize:
   r=vesicle->stepsize*rn[0];
   phi=rn[1]*2*M_PI;
   costheta=2*rn[2]-1;
   sintheta=sqrt(1-pow(costheta,2));
   vtx->x=vtx->x+r*sintheta*cos(phi);
   vtx->y=vtx->y+r*sintheta*sin(phi);
   vtx->z=vtx->z+r*costheta;


   //distance with neighbours check
   for(i=0;i<vtx->neigh_no;i++){
      dist=vtx_distance_sq(vtx,vtx->neigh[i]);
      if(dist<1.0 || dist>vesicle->dmax) {
         vtx=memcpy((void *)vtx,(void *)&backupvtx,sizeof(ts_vertex));
         return TS_FAIL;
      }
   }

// Distance with grafted vesicle-vertex check:	
   if(vtx==poly->vlist->vtx[0]){
      dist=vtx_distance_sq(vtx,poly->grafted_vtx);
        if(dist<1.0 || dist>vesicle->dmax) {
      vtx=memcpy((void *)vtx,(void *)&backupvtx,sizeof(ts_vertex));
      return TS_FAIL;
      }
   }


   //self avoidance check with distant vertices
   cellidx=vertex_self_avoidance(vesicle, vtx);
   //check occupation number
   retval=cell_occupation_number_and_internal_proximity(vesicle->clist,cellidx,vtx);
	
   if(retval==TS_FAIL){
      vtx=memcpy((void *)vtx,(void *)&backupvtx,sizeof(ts_vertex));
        return TS_FAIL;
   } 


   //if all the tests are successful, then energy for vtx and neighbours is calculated
/* Energy ignored for now!
   delta_energy=0;
   for(i=0;i<vtx->bond_no;i++){
      memcpy((void *)&backupbond[i],(void *)vtx->bond[i],sizeof(ts_bond));

      vtx->bond[i]->bond_length=sqrt(vtx_distance_sq(vtx->bond[i]->vtx1,vtx->bond[i]->vtx2));
      bond_energy(vtx->bond[i],poly);
      delta_energy+= vtx->bond[i]->energy - backupbond[i].energy;
   }

   if(vtx==poly->vlist->vtx[0]){
      delta_energy+=
         (pow(sqrt(vtx_distance_sq(vtx, poly->grafted_vtx)-1),2)-
         pow(sqrt(vtx_distance_sq(&backupvtx, poly->grafted_vtx)-1),2)) *poly->k;
		
   }


   if(delta_energy>=0){
#ifdef TS_DOUBLE_DOUBLE
        if(exp(-delta_energy)< drand48() )
#endif
#ifdef TS_DOUBLE_FLOAT
        if(expf(-delta_energy)< (ts_float)drand48())
#endif
#ifdef TS_DOUBLE_LONGDOUBLE
        if(expl(-delta_energy)< (ts_ldouble)drand48())
#endif
       {
   //not accepted, reverting changes
   vtx=memcpy((void *)vtx,(void *)&backupvtx,sizeof(ts_vertex));
   for(i=0;i<vtx->bond_no;i++){
   vtx->bond[i]=memcpy((void *)vtx->bond[i],(void *)&backupbond[i],sizeof(ts_bond));
   }

    return TS_FAIL; 
   }
   }
*/
		
//   oldcellidx=vertex_self_avoidance(vesicle, &backupvtx[0]);
   if(vtx->cell!=vesicle->clist->cell[cellidx]){
      retval=cell_add_vertex(vesicle->clist->cell[cellidx],vtx);
//      if(retval==TS_SUCCESS) cell_remove_vertex(vesicle->clist->cell[oldcellidx],vtx);
      if(retval==TS_SUCCESS) cell_remove_vertex(backupvtx.cell,vtx);	
   }
//   if(oldcellidx);
    //END MONTE CARLOOOOOOO
    return TS_SUCCESS;
}




ts_bool single_filament_vertex_move(ts_vesicle *vesicle,ts_poly *poly,ts_vertex *vtx,ts_double *rn){
   ts_uint i;
   ts_bool retval; 
   ts_uint cellidx; 
   ts_double delta_energy;
   ts_double costheta,sintheta,phi,r;
   ts_double dist[2];
   //This will hold all the information of vtx and its neighbours
   ts_vertex backupvtx,backupneigh[2];
   ts_bond backupbond[2];

   //backup vertex:		
   memcpy((void *)&backupvtx,(void *)vtx,sizeof(ts_vertex));

   //random move in a sphere with radius stepsize:
   r=vesicle->stepsize*rn[0];
   phi=rn[1]*2*M_PI;
   costheta=2*rn[2]-1;
   sintheta=sqrt(1-pow(costheta,2));
   vtx->x=vtx->x+r*sintheta*cos(phi);
   vtx->y=vtx->y+r*sintheta*sin(phi);
   vtx->z=vtx->z+r*costheta;


   //distance with neighbours check
   for(i=0;i<vtx->bond_no;i++){
      dist[i]=vtx_distance_sq(vtx->bond[i]->vtx1,vtx->bond[i]->vtx2);
      if(dist[i]<1.0 || dist[i]>vesicle->dmax) {
         vtx=memcpy((void *)vtx,(void *)&backupvtx,sizeof(ts_vertex));
         return TS_FAIL;
      }
   }

// TODO: Maybe faster if checks only nucleus-neighboring cells
// Nucleus penetration check:
   if (vtx->x*vtx->x + vtx->y*vtx->y + vtx->z*vtx->z < vesicle->R_nucleus){
      vtx=memcpy((void *)vtx,(void *)&backupvtx,sizeof(ts_vertex));
      return TS_FAIL;
   }


   //self avoidance check with distant vertices
   cellidx=vertex_self_avoidance(vesicle, vtx);
   //check occupation number
   retval=cell_occupation_number_and_internal_proximity(vesicle->clist,cellidx,vtx);
   if(retval==TS_FAIL){
      vtx=memcpy((void *)vtx,(void *)&backupvtx,sizeof(ts_vertex));
        return TS_FAIL;
   } 

   //backup bonds
   for(i=0;i<vtx->bond_no;i++){
      memcpy(&backupbond[i],vtx->bond[i], sizeof(ts_bond));
      vtx->bond[i]->bond_length=sqrt(dist[i]);
      bond_vector(vtx->bond[i]);
   }

   //backup neighboring vertices:
   for(i=0;i<vtx->neigh_no;i++){
      memcpy(&backupneigh[i],vtx->neigh[i], sizeof(ts_vertex));
   }
	
   //if all the tests are successful, then energy for vtx and neighbours is calculated
   delta_energy=0;
	
   if(vtx->bond_no == 2){
      vtx->energy = -(vtx->bond[0]->x*vtx->bond[1]->x + vtx->bond[0]->y*vtx->bond[1]->y + vtx->bond[0]->z*vtx->bond[1]->z)/vtx->bond[0]->bond_length/vtx->bond[1]->bond_length;
      delta_energy += vtx->energy - backupvtx.energy;
   }

   for(i=0;i<vtx->neigh_no;i++){
      if(vtx->neigh[i]->bond_no == 2){
         vtx->neigh[i]->energy = -(vtx->neigh[i]->bond[0]->x*vtx->neigh[i]->bond[1]->x + vtx->neigh[i]->bond[0]->y*vtx->neigh[i]->bond[1]->y + vtx->neigh[i]->bond[0]->z*vtx->neigh[i]->bond[1]->z)/vtx->neigh[i]->bond[0]->bond_length/vtx->neigh[i]->bond[1]->bond_length;
         delta_energy += vtx->neigh[i]->energy - backupneigh[i].energy;
      }
   }

   // poly->k is filament persistence length (in units l_min)
   delta_energy *= poly->k;

   if(delta_energy>=0){
#ifdef TS_DOUBLE_DOUBLE
        if(exp(-delta_energy)< drand48() )
#endif
#ifdef TS_DOUBLE_FLOAT
        if(expf(-delta_energy)< (ts_float)drand48())
#endif
#ifdef TS_DOUBLE_LONGDOUBLE
        if(expl(-delta_energy)< (ts_ldouble)drand48())
#endif
       {
   //not accepted, reverting changes
   vtx=memcpy((void *)vtx,(void *)&backupvtx,sizeof(ts_vertex));
   for(i=0;i<vtx->neigh_no;i++){
      memcpy(vtx->neigh[i],&backupneigh[i],sizeof(ts_vertex));
   }
   for(i=0;i<vtx->bond_no;i++){
      vtx->bond[i]=memcpy((void *)vtx->bond[i],(void *)&backupbond[i],sizeof(ts_bond));
   }

    return TS_FAIL; 
   }
   }
	
	
//   oldcellidx=vertex_self_avoidance(vesicle, &backupvtx[0]);
   if(vtx->cell!=vesicle->clist->cell[cellidx]){
      retval=cell_add_vertex(vesicle->clist->cell[cellidx],vtx);
//      if(retval==TS_SUCCESS) cell_remove_vertex(vesicle->clist->cell[oldcellidx],vtx);
      if(retval==TS_SUCCESS) cell_remove_vertex(backupvtx.cell,vtx);	
   }
//   if(oldcellidx);
    //END MONTE CARLOOOOOOO
    return TS_SUCCESS;
}