X-Git-Url: https://hackdaworld.org/gitweb/?a=blobdiff_plain;f=moldyn.c;h=c130ef442b838175272e62f375daa4fbaa8e199b;hb=58fd691b276fbe87593036714f26dbfe7486cbeb;hp=94d596e91878237cf41a127cd8aa947cbcd18997;hpb=fb951c04e522e4637618bf622fc67194c2a7b15f;p=physik%2Fposic.git

diff --git a/moldyn.c b/moldyn.c
index 94d596e..c130ef4 100644
--- a/moldyn.c
+++ b/moldyn.c
@@ -16,6 +16,7 @@
 #include <math.h>
 
 #include "moldyn.h"
+#include "report/report.h"
 
 int moldyn_init(t_moldyn *moldyn,int argc,char **argv) {
 
@@ -72,7 +73,7 @@ int set_temperature(t_moldyn *moldyn,double t_ref) {
 
 	moldyn->t_ref=t_ref;
 
-	printf("[moldyn] temperature: %f\n",moldyn->t_ref);
+	printf("[moldyn] temperature [K]: %f\n",moldyn->t_ref);
 
 	return 0;
 }
@@ -81,7 +82,7 @@ int set_pressure(t_moldyn *moldyn,double p_ref) {
 
 	moldyn->p_ref=p_ref;
 
-	printf("[moldyn] pressure: %f\n",moldyn->p_ref);
+	printf("[moldyn] pressure [bar]: %f\n",moldyn->p_ref/BAR);
 
 	return 0;
 }
@@ -121,7 +122,7 @@ int set_dim(t_moldyn *moldyn,double x,double y,double z,u8 visualize) {
 		moldyn->vis.dim.z=z;
 	}
 
-	moldyn->dv=0.0001*moldyn->volume;
+	moldyn->dv=0.000001*moldyn->volume;
 
 	printf("[moldyn] dimensions in A and A^3 respectively:\n");
 	printf("  x: %f\n",moldyn->dim.x);
@@ -161,34 +162,58 @@ int set_pbc(t_moldyn *moldyn,u8 x,u8 y,u8 z) {
 	return 0;
 }
 
-int set_potential1b(t_moldyn *moldyn,pf_func1b func,void *params) {
+int set_potential1b(t_moldyn *moldyn,pf_func1b func) {
 
 	moldyn->func1b=func;
-	moldyn->pot1b_params=params;
 
 	return 0;
 }
 
-int set_potential2b(t_moldyn *moldyn,pf_func2b func,void *params) {
+int set_potential2b(t_moldyn *moldyn,pf_func2b func) {
 
 	moldyn->func2b=func;
-	moldyn->pot2b_params=params;
 
 	return 0;
 }
 
-int set_potential2b_post(t_moldyn *moldyn,pf_func2b_post func,void *params) {
+int set_potential3b_j1(t_moldyn *moldyn,pf_func2b func) {
 
-	moldyn->func2b_post=func;
-	moldyn->pot2b_params=params;
+	moldyn->func3b_j1=func;
 
 	return 0;
 }
 
-int set_potential3b(t_moldyn *moldyn,pf_func3b func,void *params) {
+int set_potential3b_j2(t_moldyn *moldyn,pf_func2b func) {
 
-	moldyn->func3b=func;
-	moldyn->pot3b_params=params;
+	moldyn->func3b_j2=func;
+
+	return 0;
+}
+
+int set_potential3b_j3(t_moldyn *moldyn,pf_func2b func) {
+
+	moldyn->func3b_j3=func;
+
+	return 0;
+}
+
+int set_potential3b_k1(t_moldyn *moldyn,pf_func3b func) {
+
+	moldyn->func3b_k1=func;
+
+	return 0;
+}
+
+int set_potential3b_k2(t_moldyn *moldyn,pf_func3b func) {
+
+	moldyn->func3b_k2=func;
+
+	return 0;
+}
+
+int set_potential_params(t_moldyn *moldyn,void *params) {
+
+	moldyn->pot_params=params;
 
 	return 0;
 }
@@ -199,6 +224,14 @@ int moldyn_set_log_dir(t_moldyn *moldyn,char *dir) {
 
 	return 0;
 }
+
+int moldyn_set_report(t_moldyn *moldyn,char *author,char *title) {
+
+	strncpy(moldyn->rauthor,author,63);
+	strncpy(moldyn->rtitle,title,63);
+
+	return 0;
+}
 	
 int moldyn_set_log(t_moldyn *moldyn,u8 type,int timer) {
 
@@ -234,6 +267,32 @@ int moldyn_set_log(t_moldyn *moldyn,u8 type,int timer) {
 			dprintf(moldyn->efd,"# total momentum log file\n");
 			printf("total momentum (%d)\n",timer);
 			break;
+		case LOG_PRESSURE:
+			moldyn->pwrite=timer;
+			snprintf(filename,127,"%s/pressure",moldyn->vlsdir);
+			moldyn->pfd=open(filename,
+			                 O_WRONLY|O_CREAT|O_EXCL,
+			                 S_IRUSR|S_IWUSR);
+			if(moldyn->pfd<0) {
+				perror("[moldyn] pressure log file\n");
+				return moldyn->pfd;
+			}
+			dprintf(moldyn->pfd,"# pressure log file\n");
+			printf("pressure (%d)\n",timer);
+			break;
+		case LOG_TEMPERATURE:
+			moldyn->twrite=timer;
+			snprintf(filename,127,"%s/temperature",moldyn->vlsdir);
+			moldyn->tfd=open(filename,
+			                 O_WRONLY|O_CREAT|O_EXCL,
+			                 S_IRUSR|S_IWUSR);
+			if(moldyn->tfd<0) {
+				perror("[moldyn] temperature log file\n");
+				return moldyn->tfd;
+			}
+			dprintf(moldyn->tfd,"# temperature log file\n");
+			printf("temperature (%d)\n",timer);
+			break;
 		case SAVE_STEP:
 			moldyn->swrite=timer;
 			printf("save file (%d)\n",timer);
@@ -247,6 +306,62 @@ int moldyn_set_log(t_moldyn *moldyn,u8 type,int timer) {
 			}
 			printf("visual file (%d)\n",timer);
 			break;
+		case CREATE_REPORT:
+			snprintf(filename,127,"%s/report.tex",moldyn->vlsdir);
+			moldyn->rfd=open(filename,
+			                 O_WRONLY|O_CREAT|O_EXCL,
+			                 S_IRUSR|S_IWUSR);
+			if(moldyn->rfd<0) {
+				perror("[moldyn] report fd open");	
+				return moldyn->rfd;
+			}
+			printf("report -> ");
+			if(moldyn->efd) {
+				snprintf(filename,127,"%s/e_plot.scr",
+				         moldyn->vlsdir);
+				moldyn->epfd=open(filename,
+			 	                 O_WRONLY|O_CREAT|O_EXCL,
+			  	                 S_IRUSR|S_IWUSR);
+				if(moldyn->epfd<0) {
+					perror("[moldyn] energy plot fd open");
+					return moldyn->epfd;
+				}
+				dprintf(moldyn->epfd,e_plot_script);
+				close(moldyn->epfd);
+				printf("energy ");
+			}
+			if(moldyn->pfd) {
+				snprintf(filename,127,"%s/pressure_plot.scr",
+				         moldyn->vlsdir);
+				moldyn->ppfd=open(filename,
+			 	                  O_WRONLY|O_CREAT|O_EXCL,
+			  	                  S_IRUSR|S_IWUSR);
+				if(moldyn->ppfd<0) {
+					perror("[moldyn] p plot fd open");
+					return moldyn->ppfd;
+				}
+				dprintf(moldyn->ppfd,pressure_plot_script);
+				close(moldyn->ppfd);
+				printf("pressure ");
+			}
+			if(moldyn->tfd) {
+				snprintf(filename,127,"%s/temperature_plot.scr",
+				         moldyn->vlsdir);
+				moldyn->tpfd=open(filename,
+			 	                  O_WRONLY|O_CREAT|O_EXCL,
+			  	                  S_IRUSR|S_IWUSR);
+				if(moldyn->tpfd<0) {
+					perror("[moldyn] t plot fd open");
+					return moldyn->tpfd;
+				}
+				dprintf(moldyn->tpfd,temperature_plot_script);
+				close(moldyn->tpfd);
+				printf("temperature ");
+			}
+			dprintf(moldyn->rfd,report_start,
+			        moldyn->rauthor,moldyn->rtitle);
+			printf("\n");
+			break;
 		default:
 			printf("unknown log type: %02x\n",type);
 			return -1;
@@ -257,9 +372,48 @@ int moldyn_set_log(t_moldyn *moldyn,u8 type,int timer) {
 
 int moldyn_log_shutdown(t_moldyn *moldyn) {
 
+	char sc[256];
+
 	printf("[moldyn] log shutdown\n");
-	if(moldyn->efd) close(moldyn->efd);
+	if(moldyn->efd) {
+		close(moldyn->efd);
+		if(moldyn->rfd) {
+			dprintf(moldyn->rfd,report_energy);
+			snprintf(sc,255,"cd %s && gnuplot e_plot.scr",
+			         moldyn->vlsdir);
+			system(sc);
+		}
+	}
 	if(moldyn->mfd) close(moldyn->mfd);
+	if(moldyn->pfd) {
+		close(moldyn->pfd);
+		if(moldyn->rfd)
+			dprintf(moldyn->rfd,report_pressure);
+			snprintf(sc,255,"cd %s && gnuplot pressure_plot.scr",
+			         moldyn->vlsdir);
+			system(sc);
+	}
+	if(moldyn->tfd) {
+		close(moldyn->tfd);
+		if(moldyn->rfd)
+			dprintf(moldyn->rfd,report_temperature);
+			snprintf(sc,255,"cd %s && gnuplot temperature_plot.scr",
+			         moldyn->vlsdir);
+			system(sc);
+	}
+	if(moldyn->rfd) {
+		dprintf(moldyn->rfd,report_end);
+		close(moldyn->rfd);
+		snprintf(sc,255,"cd %s && pdflatex report >/dev/null 2>&1",
+		         moldyn->vlsdir);
+		system(sc);
+		snprintf(sc,255,"cd %s && pdflatex report >/dev/null 2>&1",
+		         moldyn->vlsdir);
+		system(sc);
+		snprintf(sc,255,"cd %s && dvipdf report >/dev/null 2>&1",
+		         moldyn->vlsdir);
+		system(sc);
+	}
 	if(&(moldyn->vis)) visual_tini(&(moldyn->vis));
 
 	return 0;
@@ -270,11 +424,11 @@ int moldyn_log_shutdown(t_moldyn *moldyn) {
  */
 
 int create_lattice(t_moldyn *moldyn,u8 type,double lc,int element,double mass,
-                   u8 attr,u8 brand,int a,int b,int c) {
+                   u8 attr,u8 brand,int a,int b,int c,t_3dvec *origin) {
 
 	int new,count;
 	int ret;
-	t_3dvec origin;
+	t_3dvec orig;
 	void *ptr;
 	t_atom *atom;
 
@@ -294,18 +448,35 @@ int create_lattice(t_moldyn *moldyn,u8 type,double lc,int element,double mass,
 	}
 	moldyn->atom=ptr;
 	atom=&(moldyn->atom[count]);
-		
-	v3_zero(&origin);
+
+	/* no atoms on the boundaries (only reason: it looks better!) */
+	if(!origin) {
+		orig.x=0.5*lc;
+		orig.y=0.5*lc;
+		orig.z=0.5*lc;
+	}
+	else {
+		orig.x=origin->x;
+		orig.y=origin->y;
+		orig.z=origin->z;
+	}
 
 	switch(type) {
 		case CUBIC:
-			ret=cubic_init(a,b,c,atom,&origin);
+			set_nn_dist(moldyn,lc);
+			ret=cubic_init(a,b,c,lc,atom,&orig);
 			break;
 		case FCC:
-			ret=fcc_init(a,b,c,lc,atom,&origin);
+			if(!origin)
+				v3_scale(&orig,&orig,0.5);
+			set_nn_dist(moldyn,0.5*sqrt(2.0)*lc);
+			ret=fcc_init(a,b,c,lc,atom,&orig);
 			break;
 		case DIAMOND:
-			ret=diamond_init(a,b,c,lc,atom,&origin);
+			if(!origin)
+				v3_scale(&orig,&orig,0.25);
+			set_nn_dist(moldyn,0.25*sqrt(3.0)*lc);
+			ret=diamond_init(a,b,c,lc,atom,&orig);
 			break;
 		default:
 			printf("unknown lattice type (%02x)\n",type);
@@ -340,74 +511,93 @@ int create_lattice(t_moldyn *moldyn,u8 type,double lc,int element,double mass,
 int cubic_init(int a,int b,int c,double lc,t_atom *atom,t_3dvec *origin) {
 
 	int count;
-	t_3dvec r
+	t_3dvec r;
+	int i,j,k;
+	t_3dvec o;
+
+	count=0;
+	if(origin)
+		v3_copy(&o,origin);
+	else
+		v3_zero(&o);
 
-HIER WEITER !
+	r.x=o.x;
+	for(i=0;i<a;i++) {
+		r.y=o.y;
+		for(j=0;j<b;j++) {
+			r.z=o.z;
+			for(k=0;k<c;k++) {
+				v3_copy(&(atom[count].r),&r);
+				count+=1;
+				r.z+=lc;
+			}
+			r.y+=lc;
+		}
+		r.x+=lc;
+	}
+
+	for(i=0;i<count;i++) {
+		atom[i].r.x-=(a*lc)/2.0;
+		atom[i].r.y-=(b*lc)/2.0;
+		atom[i].r.z-=(c*lc)/2.0;
+	}
+
+	return count;
 }
 
 /* fcc lattice init */
 int fcc_init(int a,int b,int c,double lc,t_atom *atom,t_3dvec *origin) {
 
 	int count;
-	int i,j;
+	int i,j,k,l;
 	t_3dvec o,r,n;
 	t_3dvec basis[3];
-	double help[3];
-	double x,y,z;
-
-	x=a*lc;
-	y=b*lc;
-	z=c*lc;
 
-	if(origin) v3_copy(&o,origin);
-	else v3_zero(&o);
+	count=0;
+	if(origin)
+		v3_copy(&o,origin);
+	else
+		v3_zero(&o);
 
 	/* construct the basis */
-	for(i=0;i<3;i++) {
-		for(j=0;j<3;j++) {
-			if(i!=j) help[j]=0.5*lc;
-			else help[j]=.0;
-		}
-		v3_set(&basis[i],help);
-	}
+	memset(basis,0,3*sizeof(t_3dvec));
+	basis[0].x=0.5*lc;
+	basis[0].y=0.5*lc;
+	basis[1].x=0.5*lc;
+	basis[1].z=0.5*lc;
+	basis[2].y=0.5*lc;
+	basis[2].z=0.5*lc;
 
-	v3_zero(&r);
-	count=0;
-	
 	/* fill up the room */
 	r.x=o.x;
-	while(r.x<x) {
+	for(i=0;i<a;i++) {
 		r.y=o.y;
-		while(r.y<y) {
+		for(j=0;j<b;j++) {
 			r.z=o.z;
-			while(r.z<z) {
+			for(k=0;k<c;k++) {
+				/* first atom */
 				v3_copy(&(atom[count].r),&r);
-				atom[count].element=1;
 				count+=1;
-				for(i=0;i<3;i++) {
-					v3_add(&n,&r,&basis[i]);
-					if((n.x<x+o.x)&&
-					   (n.y<y+o.y)&&
-					   (n.z<z+o.z)) {
-						v3_copy(&(atom[count].r),&n);
-						count+=1;
-					}
+				r.z+=lc;
+				/* the three face centered atoms */
+				for(l=0;l<3;l++) {
+					v3_add(&n,&r,&basis[l]);
+					v3_copy(&(atom[count].r),&n);
+					count+=1;
 				}
-				r.z+=lc;	
 			}
 			r.y+=lc;
 		}
 		r.x+=lc;
 	}
-
+				
 	/* coordinate transformation */
-	help[0]=x/2.0;
-	help[1]=y/2.0;
-	help[2]=z/2.0;
-	v3_set(&n,help);
-	for(i=0;i<count;i++)
-		v3_sub(&(atom[i].r),&(atom[i].r),&n);
-		
+	for(i=0;i<count;i++) {
+		atom[i].r.x-=(a*lc)/2.0;
+		atom[i].r.y-=(b*lc)/2.0;
+		atom[i].r.z-=(c*lc)/2.0;
+	}
+
 	return count;
 }
 
@@ -517,18 +707,11 @@ int thermal_init(t_moldyn *moldyn,u8 equi_init) {
 
 double temperature_calc(t_moldyn *moldyn) {
 
-	double double_ekin;
-	int i;
-	t_atom *atom;
-
-	atom=moldyn->atom;
+	/* assume up to date kinetic energy, which is 3/2 N k_B T */
 
-	double_ekin=0;
-	for(i=0;i<moldyn->count;i++)
-		double_ekin+=atom[i].mass*v3_absolute_square(&(atom[i].v));
-
-	/* kinetic energy = 3/2 N k_B T */
-	moldyn->t=double_ekin/(3.0*K_BOLTZMANN*moldyn->count);
+	moldyn->t=(2.0*moldyn->ekin)/(3.0*K_BOLTZMANN*moldyn->count);
+	moldyn->t_sum+=moldyn->t;
+	moldyn->mean_t=moldyn->t_sum/moldyn->total_steps;
 
 	return moldyn->t;
 }
@@ -599,7 +782,6 @@ double ideal_gas_law_pressure(t_moldyn *moldyn) {
 	double p;
 
 	p=moldyn->count*moldyn->t*K_BOLTZMANN/moldyn->volume;
-printf("temp = %f => ideal gas law pressure: %f\n",moldyn->t,p/ATM);
 
 	return p;
 }
@@ -607,27 +789,40 @@ printf("temp = %f => ideal gas law pressure: %f\n",moldyn->t,p/ATM);
 double pressure_calc(t_moldyn *moldyn) {
 
 	int i;
-	double p1,p;
-	double v,h;
+	double v;
 	t_virial *virial;
 
+	/*
+	 * PV = NkT + <W>
+	 * W = 1/3 sum_i f_i r_i
+	 * virial = sum_i f_i r_i
+	 * 
+	 * => P = (2 Ekin + virial) / (3V)
+	 */
+
 	v=0.0;
 	for(i=0;i<moldyn->count;i++) {
 		virial=&(moldyn->atom[i].virial);
 		v+=(virial->xx+virial->yy+virial->zz);
 	}
 
-	h=moldyn->count*K_BOLTZMANN*moldyn->t;
-
-	p=(h-ONE_THIRD*v);
-	p/=moldyn->volume;
-
-	p1=(moldyn->count*K_BOLTZMANN*moldyn->t-ONE_THIRD*moldyn->vt1);
-	p1/=moldyn->volume;
+	/* virial sum and mean virial */
+	moldyn->virial_sum+=v;
+	moldyn->mean_v=moldyn->virial_sum/moldyn->total_steps;
 
-	printf("debug: vt1=%f v=%f nkt=%f\n",moldyn->vt1,v,h);
+	/* assume up to date kinetic energy */
+	moldyn->p=2.0*moldyn->ekin+moldyn->mean_v;
+	moldyn->p/=(3.0*moldyn->volume);
+	moldyn->p_sum+=moldyn->p;
+	moldyn->mean_p=moldyn->p_sum/moldyn->total_steps;
 
-	printf("compare pressures: %f %f %f\n",p1/ATM,p/ATM,h/moldyn->volume/ATM);
+	/* pressure from 'absolute coordinates' virial */
+	virial=&(moldyn->virial);
+	v=virial->xx+virial->yy+virial->zz;
+	moldyn->gp=2.0*moldyn->ekin+v;
+	moldyn->gp/=(3.0*moldyn->volume);
+	moldyn->gp_sum+=moldyn->gp;
+	moldyn->mean_gp=moldyn->gp_sum/moldyn->total_steps;
 
 	return moldyn->p;
 }	
@@ -635,11 +830,20 @@ double pressure_calc(t_moldyn *moldyn) {
 double thermodynamic_pressure_calc(t_moldyn *moldyn) {
 
 	t_3dvec dim,*tp;
-	double u,p;
-	double scale;
+	double u_up,u_down,dv;
+	double scale,p;
 	t_atom *store;
 
-	tp=&(moldyn->tp);
+	/*
+	 * dU = - p dV
+	 *
+	 * => p = - dU/dV
+	 *
+	 */
+
+	scale=0.00001;
+	dv=8*scale*scale*scale*moldyn->volume;
+
 	store=malloc(moldyn->count*sizeof(t_atom));
 	if(store==NULL) {
 		printf("[moldyn] allocating store mem failed\n");
@@ -647,64 +851,44 @@ double thermodynamic_pressure_calc(t_moldyn *moldyn) {
 	}
 
 	/* save unscaled potential energy + atom/dim configuration */
-	u=moldyn->energy;
 	memcpy(store,moldyn->atom,moldyn->count*sizeof(t_atom));
 	dim=moldyn->dim;
 
-	/* derivative with respect to x direction */
-	scale=1.0+moldyn->dv/(moldyn->dim.y*moldyn->dim.z);
-	scale_dim(moldyn,scale,TRUE,0,0);
-	scale_atoms(moldyn,scale,TRUE,0,0);
-	potential_force_calc(moldyn);
-	tp->x=(moldyn->energy-u)/moldyn->dv;
-	p=tp->x*tp->x;
-
-	/* restore atomic configuration + dim */
-	memcpy(moldyn->atom,store,moldyn->count*sizeof(t_atom));
-	moldyn->dim=dim;
-
-	/* derivative with respect to y direction */
-	scale=1.0+moldyn->dv/(moldyn->dim.x*moldyn->dim.z);
-	scale_dim(moldyn,scale,0,TRUE,0);
-	scale_atoms(moldyn,scale,0,TRUE,0);
+	/* scale up dimension and atom positions */
+	scale_dim(moldyn,SCALE_UP,scale,TRUE,TRUE,TRUE);
+	scale_atoms(moldyn,SCALE_UP,scale,TRUE,TRUE,TRUE);
+	link_cell_shutdown(moldyn);
+	link_cell_init(moldyn,QUIET);
 	potential_force_calc(moldyn);
-	tp->y=(moldyn->energy-u)/moldyn->dv;
-	p+=tp->y*tp->y;
+	u_up=moldyn->energy;
 
 	/* restore atomic configuration + dim */
 	memcpy(moldyn->atom,store,moldyn->count*sizeof(t_atom));
 	moldyn->dim=dim;
 
-	/* derivative with respect to z direction */
-	scale=1.0+moldyn->dv/(moldyn->dim.x*moldyn->dim.y);
-	scale_dim(moldyn,scale,0,0,TRUE);
-	scale_atoms(moldyn,scale,0,0,TRUE);
+	/* scale down dimension and atom positions */
+	scale_dim(moldyn,SCALE_DOWN,scale,TRUE,TRUE,TRUE);
+	scale_atoms(moldyn,SCALE_DOWN,scale,TRUE,TRUE,TRUE);
+	link_cell_shutdown(moldyn);
+	link_cell_init(moldyn,QUIET);
 	potential_force_calc(moldyn);
-	tp->z=(moldyn->energy-u)/moldyn->dv;
-	p+=tp->z*tp->z;
+	u_down=moldyn->energy;
+	
+	/* calculate pressure */
+	p=-(u_up-u_down)/dv;
+printf("-------> %.10f %.10f %f\n",u_up/EV/moldyn->count,u_down/EV/moldyn->count,p/BAR);
 
 	/* restore atomic configuration + dim */
 	memcpy(moldyn->atom,store,moldyn->count*sizeof(t_atom));
 	moldyn->dim=dim;
 
-	printf("dU/dV komp addiert = %f\n",(tp->x+tp->y+tp->z)/ATM);
-
-	scale=1.0+pow(moldyn->dv/moldyn->volume,ONE_THIRD);
-
-	scale_dim(moldyn,scale,1,1,1);
-	scale_dim(moldyn,scale,1,1,1);
+	/* restore energy */
 	potential_force_calc(moldyn);
 
-	printf("dU/dV einfach = %f\n",(moldyn->energy-u)/moldyn->dv/ATM);
-
-	/* restore atomic configuration + dim */
-	memcpy(moldyn->atom,store,moldyn->count*sizeof(t_atom));
-	moldyn->dim=dim;
-
-	/* restore energy */
-	moldyn->energy=u;
+	link_cell_shutdown(moldyn);
+	link_cell_init(moldyn,QUIET);
 
-	return sqrt(p);
+	return p;
 }
 
 double get_pressure(t_moldyn *moldyn) {
@@ -713,12 +897,18 @@ double get_pressure(t_moldyn *moldyn) {
 
 }
 
-int scale_dim(t_moldyn *moldyn,double scale,u8 x,u8 y,u8 z) {
+int scale_dim(t_moldyn *moldyn,u8 dir,double scale,u8 x,u8 y,u8 z) {
 
 	t_3dvec *dim;
 
 	dim=&(moldyn->dim);
 
+	if(dir==SCALE_UP)
+		scale=1.0+scale;
+
+	if(dir==SCALE_DOWN)
+		scale=1.0-scale;
+
 	if(x) dim->x*=scale;
 	if(y) dim->y*=scale;
 	if(z) dim->z*=scale;
@@ -726,11 +916,17 @@ int scale_dim(t_moldyn *moldyn,double scale,u8 x,u8 y,u8 z) {
 	return 0;
 }
 
-int scale_atoms(t_moldyn *moldyn,double scale,u8 x,u8 y,u8 z) {
+int scale_atoms(t_moldyn *moldyn,u8 dir,double scale,u8 x,u8 y,u8 z) {
 
 	int i;
 	t_3dvec *r;
 
+	if(dir==SCALE_UP)
+		scale=1.0+scale;
+
+	if(dir==SCALE_DOWN)
+		scale=1.0-scale;
+
 	for(i=0;i<moldyn->count;i++) {
 		r=&(moldyn->atom[i].r);
 		if(x) r->x*=scale;
@@ -743,68 +939,55 @@ int scale_atoms(t_moldyn *moldyn,double scale,u8 x,u8 y,u8 z) {
 
 int scale_volume(t_moldyn *moldyn) {
 
-	t_atom *atom;
 	t_3dvec *dim,*vdim;
-	double scale,v;
-	t_virial virial;
+	double scale;
 	t_linkcell *lc;
-	int i;
 
-	atom=moldyn->atom;
-	dim=&(moldyn->dim);
 	vdim=&(moldyn->vis.dim);
+	dim=&(moldyn->dim);
 	lc=&(moldyn->lc);
 
-	memset(&virial,0,sizeof(t_virial));
+	/* scaling factor */
+	if(moldyn->pt_scale&P_SCALE_BERENDSEN) {
+		scale=1.0-(moldyn->p_ref-moldyn->p)/moldyn->p_tc;
+		scale=pow(scale,ONE_THIRD);
+	}
+	else {
+		scale=pow(moldyn->p/moldyn->p_ref,ONE_THIRD);
+	}
+moldyn->debug=scale;
 
-	for(i=0;i<moldyn->count;i++) {
-		virial.xx+=atom[i].virial.xx;
-		virial.yy+=atom[i].virial.yy;
-		virial.zz+=atom[i].virial.zz;
-		virial.xy+=atom[i].virial.xy;
-		virial.xz+=atom[i].virial.xz;
-		virial.yz+=atom[i].virial.yz;
+	/* scale the atoms and dimensions */
+	scale_atoms(moldyn,SCALE_DIRECT,scale,TRUE,TRUE,TRUE);
+	scale_dim(moldyn,SCALE_DIRECT,scale,TRUE,TRUE,TRUE);
+
+	/* visualize dimensions */
+	if(vdim->x!=0) {
+		vdim->x=dim->x;
+		vdim->y=dim->y;
+		vdim->z=dim->z;
 	}
 
-	/* just a guess so far ... */
-	v=virial.xx+virial.yy+virial.zz;
-
-printf("%f\n",v);
-	/* get pressure from virial */
-	moldyn->p=moldyn->count*K_BOLTZMANN*moldyn->t+ONE_THIRD*v;
-	moldyn->p/=moldyn->volume;
-printf("%f | %f\n",moldyn->p/(ATM),moldyn->p_ref/ATM);
-
-	/* scale factor */
-	if(moldyn->pt_scale&P_SCALE_BERENDSEN)
-		scale=3*sqrt(1-(moldyn->p_ref-moldyn->p)/moldyn->p_tc);
-	else 
-		/* should actually never be used */
-		scale=pow(moldyn->p/moldyn->p_ref,1.0/3.0);
-
-printf("scale = %f\n",scale);
-	/* actual scaling */
-	dim->x*=scale;
-	dim->y*=scale;
-	dim->z*=scale;
-	if(vdim->x) vdim->x=dim->x;
-	if(vdim->y) vdim->y=dim->y;
-	if(vdim->z) vdim->z=dim->z;
-	moldyn->volume*=(scale*scale*scale);
-
-	/* check whether we need a new linkcell init */
-	if((dim->x/moldyn->cutoff!=lc->nx)||
-	   (dim->y/moldyn->cutoff!=lc->ny)||
-	   (dim->z/moldyn->cutoff!=lc->nx)) {
+	/* recalculate scaled volume */
+	moldyn->volume=dim->x*dim->y*dim->z;
+
+	/* adjust/reinit linkcell */
+	if(((int)(dim->x/moldyn->cutoff)!=lc->nx)||
+	   ((int)(dim->y/moldyn->cutoff)!=lc->ny)||
+	   ((int)(dim->z/moldyn->cutoff)!=lc->nx)) {
 		link_cell_shutdown(moldyn);
-		link_cell_init(moldyn);
+		link_cell_init(moldyn,QUIET);
+	} else {
+		lc->x*=scale;
+		lc->y*=scale;
+		lc->z*=scale;
 	}
 
 	return 0;
 
 }
 
-double get_e_kin(t_moldyn *moldyn) {
+double e_kin_calc(t_moldyn *moldyn) {
 
 	int i;
 	t_atom *atom;
@@ -818,11 +1001,6 @@ double get_e_kin(t_moldyn *moldyn) {
 	return moldyn->ekin;
 }
 
-double update_e_kin(t_moldyn *moldyn) {
-
-	return(get_e_kin(moldyn));
-}
-
 double get_total_energy(t_moldyn *moldyn) {
 
 	return(moldyn->ekin+moldyn->energy);
@@ -862,7 +1040,7 @@ double estimate_time_step(t_moldyn *moldyn,double nn_dist) {
 
 /* linked list / cell method */
 
-int link_cell_init(t_moldyn *moldyn) {
+int link_cell_init(t_moldyn *moldyn,u8 vol) {
 
 	t_linkcell *lc;
 	int i;
@@ -883,7 +1061,12 @@ int link_cell_init(t_moldyn *moldyn) {
 	if(lc->cells<27)
 		printf("[moldyn] FATAL: less then 27 subcells!\n");
 
-	printf("[moldyn] initializing linked cells (%d)\n",lc->cells);
+	if(vol) {
+		printf("[moldyn] initializing linked cells (%d)\n",lc->cells);
+		printf("  x: %d x %f A\n",lc->nx,lc->x);
+		printf("  y: %d x %f A\n",lc->ny,lc->y);
+		printf("  z: %d x %f A\n",lc->nz,lc->z);
+	}
 
 	for(i=0;i<lc->cells;i++)
 		list_init_f(&(lc->subcell[i]));
@@ -918,7 +1101,7 @@ int link_cell_update(t_moldyn *moldyn) {
 		i=((atom[count].r.x+(moldyn->dim.x/2))/lc->x);
 		j=((atom[count].r.y+(moldyn->dim.y/2))/lc->y);
 		k=((atom[count].r.z+(moldyn->dim.z/2))/lc->z);
-		list_add_immediate_f(&(moldyn->lc.subcell[i+j*nx+k*nx*ny]),
+		list_add_immediate_f(&(lc->subcell[i+j*nx+k*nx*ny]),
 		                     &(atom[count]));
 	}
 
@@ -1047,32 +1230,42 @@ int moldyn_set_schedule_hook(t_moldyn *moldyn,set_hook hook,void *hook_params) {
 int moldyn_integrate(t_moldyn *moldyn) {
 
 	int i;
-	unsigned int e,m,s,v;
-	t_3dvec p;
+	unsigned int e,m,s,v,p,t;
+	t_3dvec momentum;
 	t_moldyn_schedule *sched;
 	t_atom *atom;
 	int fd;
 	char dir[128];
 	double ds;
+	double energy_scale;
+	//double tp;
 
 	sched=&(moldyn->schedule);
 	atom=moldyn->atom;
 
 	/* initialize linked cell method */
-	link_cell_init(moldyn);
+	link_cell_init(moldyn,VERBOSE);
 
 	/* logging & visualization */
 	e=moldyn->ewrite;
 	m=moldyn->mwrite;
 	s=moldyn->swrite;
 	v=moldyn->vwrite;
+	p=moldyn->pwrite;
+	t=moldyn->twrite;
 
 	/* sqaure of some variables */
 	moldyn->tau_square=moldyn->tau*moldyn->tau;
 	moldyn->cutoff_square=moldyn->cutoff*moldyn->cutoff;
 
+	/* energy scaling factor */
+	energy_scale=moldyn->count*EV;
+
 	/* calculate initial forces */
 	potential_force_calc(moldyn);
+#ifdef DEBUG
+return 0;
+#endif
 
 	/* some stupid checks before we actually start calculating bullshit */
 	if(moldyn->cutoff>0.5*moldyn->dim.x)
@@ -1087,6 +1280,7 @@ int moldyn_integrate(t_moldyn *moldyn) {
 
 	/* zero absolute time */
 	moldyn->time=0.0;
+	moldyn->total_steps=0;
 
 	/* debugging, ignore */
 	moldyn->debug=0;
@@ -1109,29 +1303,50 @@ int moldyn_integrate(t_moldyn *moldyn) {
 		/* integration step */
 		moldyn->integrate(moldyn);
 
+		/* calculate kinetic energy, temperature and pressure */
+		e_kin_calc(moldyn);
+		temperature_calc(moldyn);
+		pressure_calc(moldyn);
+		//tp=thermodynamic_pressure_calc(moldyn);
+//printf("thermodynamic p: %f\n",thermodynamic_pressure_calc(moldyn)/BAR);
+
 		/* p/t scaling */
 		if(moldyn->pt_scale&(T_SCALE_BERENDSEN|T_SCALE_DIRECT))
 			scale_velocity(moldyn,FALSE);
 		if(moldyn->pt_scale&(P_SCALE_BERENDSEN|P_SCALE_DIRECT))
 			scale_volume(moldyn);
 
-printf("-> %f\n",thermodynamic_pressure_calc(moldyn)/ATM);
-
 		/* check for log & visualization */
 		if(e) {
 			if(!(i%e))
-				update_e_kin(moldyn);
 				dprintf(moldyn->efd,
 				        "%f %f %f %f\n",
-				        moldyn->time,moldyn->ekin,
-				        moldyn->energy,
-				        get_total_energy(moldyn));
+				        moldyn->time,moldyn->ekin/energy_scale,
+				        moldyn->energy/energy_scale,
+				        get_total_energy(moldyn)/energy_scale);
 		}
 		if(m) {
 			if(!(i%m)) {
-				p=get_total_p(moldyn);
+				momentum=get_total_p(moldyn);
 				dprintf(moldyn->mfd,
-				        "%f %f\n",moldyn->time,v3_norm(&p));
+				        "%f %f %f %f %f\n",moldyn->time,
+				        momentum.x,momentum.y,momentum.z,
+				        v3_norm(&momentum));
+			}
+		}
+		if(p) {
+			if(!(i%p)) {
+				dprintf(moldyn->pfd,
+				        "%f %f %f %f %f\n",moldyn->time,
+				         moldyn->p/BAR,moldyn->mean_p/BAR,
+				         moldyn->gp/BAR,moldyn->mean_gp/BAR);
+			}
+		}
+		if(t) {
+			if(!(i%t)) {
+				dprintf(moldyn->tfd,
+				        "%f %f %f\n",
+				        moldyn->time,moldyn->t,moldyn->mean_t);
 			}
 		}
 		if(s) {
@@ -1152,20 +1367,30 @@ printf("-> %f\n",thermodynamic_pressure_calc(moldyn)/ATM);
 			if(!(i%v)) {
 				visual_atoms(&(moldyn->vis),moldyn->time,
 				             moldyn->atom,moldyn->count);
-				printf("\rsched: %d, steps: %d, debug: %d",
-				       sched->count,i,moldyn->debug);
-				fflush(stdout);
 			}
 		}
 
+		/* display progress */
+		if(!(i%10)) {
+			printf("\rsched: %d, steps: %d, T: %f, P: %f %f V: %f",
+			       sched->count,i,
+			       moldyn->mean_t,
+			       moldyn->mean_p/BAR,
+			       moldyn->mean_gp/BAR,
+			       moldyn->volume);
+			fflush(stdout);
+		}
+
 		/* increase absolute time */
 		moldyn->time+=moldyn->tau;
+		moldyn->total_steps+=1;
 
 	}
 
 		/* check for hooks */
-		if(sched->hook)
-			sched->hook(moldyn,sched->hook_params);
+		if(sched->count+1<sched->total_sched)
+			if(sched->hook)
+				sched->hook(moldyn,sched->hook_params);
 
 		/* get a new info line */
 		printf("\n");
@@ -1246,8 +1471,8 @@ int potential_force_calc(t_moldyn *moldyn) {
 	/* reset energy */
 	moldyn->energy=0.0;
 
-	/* reset virial */
-	moldyn->vt1=0.0;
+	/* reset global virial */
+	memset(&(moldyn->virial),0,sizeof(t_virial));
 
 	/* reset force, site energy and virial of every atom */
 	for(i=0;i<count;i++) {
@@ -1269,12 +1494,15 @@ int potential_force_calc(t_moldyn *moldyn) {
 
 	}
 
-	/* get energy,force and virial of every atom */
+	/* get energy, force and virial of every atom */
+
+	/* first (and only) loop over atoms i */
 	for(i=0;i<count;i++) {
 
 		/* single particle potential/force */
 		if(itom[i].attr&ATOM_ATTR_1BP)
-			moldyn->func1b(moldyn,&(itom[i]));
+			if(moldyn->func1b)
+				moldyn->func1b(moldyn,&(itom[i]));
 
 		if(!(itom[i].attr&(ATOM_ATTR_2BP|ATOM_ATTR_3BP)))
 			continue;
@@ -1289,6 +1517,45 @@ int potential_force_calc(t_moldyn *moldyn) {
 
 		dnlc=lc->dnlc;
 
+		/* first loop over atoms j */
+		if(moldyn->func2b) {
+			for(j=0;j<27;j++) {
+
+				this=&(neighbour_i[j]);
+				list_reset_f(this);
+
+				if(this->start==NULL)
+					continue;
+
+				bc_ij=(j<dnlc)?0:1;
+
+				do {
+					jtom=this->current->data;
+
+					if(jtom==&(itom[i]))
+						continue;
+
+					if((jtom->attr&ATOM_ATTR_2BP)&
+					   (itom[i].attr&ATOM_ATTR_2BP)) {
+						moldyn->func2b(moldyn,
+						               &(itom[i]),
+						               jtom,
+					        	       bc_ij);
+					}
+				} while(list_next_f(this)!=L_NO_NEXT_ELEMENT);
+
+			}
+		}
+
+		/* 3 body potential/force */
+
+		if(!(itom[i].attr&ATOM_ATTR_3BP))
+			continue;
+
+		/* copy the neighbour lists */
+		memcpy(neighbour_i2,neighbour_i,27*sizeof(t_list));
+
+		/* second loop over atoms j */
 		for(j=0;j<27;j++) {
 
 			this=&(neighbour_i[j]);
@@ -1305,25 +1572,70 @@ int potential_force_calc(t_moldyn *moldyn) {
 				if(jtom==&(itom[i]))
 					continue;
 
-				if((jtom->attr&ATOM_ATTR_2BP)&
-				   (itom[i].attr&ATOM_ATTR_2BP)) {
-					moldyn->func2b(moldyn,
-					               &(itom[i]),
-					               jtom,
-					               bc_ij);
-				}
+				if(!(jtom->attr&ATOM_ATTR_3BP))
+					continue;
 
-				/* 3 body potential/force */
+				/* reset 3bp run */
+				moldyn->run3bp=1;
 
-				if(!(itom[i].attr&ATOM_ATTR_3BP)||
-				   !(jtom->attr&ATOM_ATTR_3BP))
+				if(moldyn->func3b_j1)
+					moldyn->func3b_j1(moldyn,
+					                  &(itom[i]),
+					                  jtom,
+					                  bc_ij);
+
+				/* in first j loop, 3bp run can be skipped */
+				if(!(moldyn->run3bp))
 					continue;
+			
+				/* first loop over atoms k */
+				if(moldyn->func3b_k1) {
 
-				/* copy the neighbour lists */
-				memcpy(neighbour_i2,neighbour_i,
-				       27*sizeof(t_list));
+				for(k=0;k<27;k++) {
+
+					that=&(neighbour_i2[k]);
+					list_reset_f(that);
+					
+					if(that->start==NULL)
+						continue;
+
+					bc_ik=(k<dnlc)?0:1;
+
+					do {
+
+						ktom=that->current->data;
+
+						if(!(ktom->attr&ATOM_ATTR_3BP))
+							continue;
+
+						if(ktom==jtom)
+							continue;
+
+						if(ktom==&(itom[i]))
+							continue;
+
+						moldyn->func3b_k1(moldyn,
+						                  &(itom[i]),
+						                  jtom,
+						                  ktom,
+						                  bc_ik|bc_ij);
+
+					} while(list_next_f(that)!=\
+					        L_NO_NEXT_ELEMENT);
+
+				}
+
+				}
+
+				if(moldyn->func3b_j2)
+					moldyn->func3b_j2(moldyn,
+					                  &(itom[i]),
+					                  jtom,
+					                  bc_ij);
+
+				/* second loop over atoms k */
+				if(moldyn->func3b_k2) {
 
-				/* get neighbours of i */
 				for(k=0;k<27;k++) {
 
 					that=&(neighbour_i2[k]);
@@ -1347,39 +1659,52 @@ int potential_force_calc(t_moldyn *moldyn) {
 						if(ktom==&(itom[i]))
 							continue;
 
-						moldyn->func3b(moldyn,
-						               &(itom[i]),
-						               jtom,
-						               ktom,
-						               bc_ik|bc_ij);
+						moldyn->func3b_k2(moldyn,
+						                  &(itom[i]),
+						                  jtom,
+						                  ktom,
+						                  bc_ik|bc_ij);
 
 					} while(list_next_f(that)!=\
 					        L_NO_NEXT_ELEMENT);
 
 				}
+				
+				}
 
 				/* 2bp post function */
-				if(moldyn->func2b_post) {
-					moldyn->func2b_post(moldyn,
-					                    &(itom[i]),
-					                    jtom,bc_ij);
+				if(moldyn->func3b_j3) {
+					moldyn->func3b_j3(moldyn,
+					                  &(itom[i]),
+					                  jtom,bc_ij);
 				}
 					
 			} while(list_next_f(this)!=L_NO_NEXT_ELEMENT);
 		
 		}
-
-	}
+		
 #ifdef DEBUG
-printf("\n\n");
+	//printf("\n\n");
 #endif
 #ifdef VDEBUG
-printf("\n\n");
+	printf("\n\n");
+#endif
+
+	}
+
+#ifdef DEBUG
+	printf("\nATOM 0: %f %f %f\n\n",itom->f.x,itom->f.y,itom->f.z);
 #endif
 
-temperature_calc(moldyn);
-pressure_calc(moldyn);
-ideal_gas_law_pressure(moldyn);
+	/* calculate global virial */
+	for(i=0;i<count;i++) {
+		moldyn->virial.xx+=moldyn->atom[i].r.x*moldyn->atom[i].f.x;
+		moldyn->virial.yy+=moldyn->atom[i].r.y*moldyn->atom[i].f.y;
+		moldyn->virial.zz+=moldyn->atom[i].r.z*moldyn->atom[i].f.z;
+		moldyn->virial.xy+=moldyn->atom[i].r.y*moldyn->atom[i].f.x;
+		moldyn->virial.xz+=moldyn->atom[i].r.z*moldyn->atom[i].f.x;
+		moldyn->virial.yz+=moldyn->atom[i].r.z*moldyn->atom[i].f.y;
+	}
 
 	return 0;
 }
@@ -1388,23 +1713,25 @@ ideal_gas_law_pressure(moldyn);
  * virial calculation
  */
 
-inline int virial_calc(t_atom *a,t_3dvec *f,t_3dvec *d) {
+//inline int virial_calc(t_atom *a,t_3dvec *f,t_3dvec *d) {
+int virial_calc(t_atom *a,t_3dvec *f,t_3dvec *d) {
 
-	a->virial.xx-=f->x*d->x;
-	a->virial.yy-=f->y*d->y;
-	a->virial.zz-=f->z*d->z;
-	a->virial.xy-=f->x*d->y;
-	a->virial.xz-=f->x*d->z;
-	a->virial.yz-=f->y*d->z;
+	a->virial.xx+=f->x*d->x;
+	a->virial.yy+=f->y*d->y;
+	a->virial.zz+=f->z*d->z;
+	a->virial.xy+=f->x*d->y;
+	a->virial.xz+=f->x*d->z;
+	a->virial.yz+=f->y*d->z;
 
 	return 0;
 }
 
 /*
- * periodic boundayr checking
+ * periodic boundary checking
  */
 
-inline int check_per_bound(t_moldyn *moldyn,t_3dvec *a) {
+//inline int check_per_bound(t_moldyn *moldyn,t_3dvec *a) {
+int check_per_bound(t_moldyn *moldyn,t_3dvec *a) {
 	
 	double x,y,z;
 	t_3dvec *dim;
@@ -1431,779 +1758,6 @@ inline int check_per_bound(t_moldyn *moldyn,t_3dvec *a) {
 	return 0;
 }
         
-
-/*
- * example potentials
- */
-
-/* harmonic oscillator potential and force */
-
-int harmonic_oscillator(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
-
-	t_ho_params *params;
-	t_3dvec force,distance;
-	double d,f;
-	double sc,equi_dist;
-
-	params=moldyn->pot2b_params;
-	sc=params->spring_constant;
-	equi_dist=params->equilibrium_distance;
-
-	if(ai<aj) return 0;
-
-	v3_sub(&distance,&(aj->r),&(ai->r));
-	
-	if(bc) check_per_bound(moldyn,&distance);
-	d=v3_norm(&distance);
-	if(d<=moldyn->cutoff) {
-		moldyn->energy+=(0.5*sc*(d-equi_dist)*(d-equi_dist));
-		/* f = -grad E; grad r_ij = -1 1/r_ij distance */
-		f=sc*(1.0-equi_dist/d);
-		v3_scale(&force,&distance,f);
-		v3_add(&(ai->f),&(ai->f),&force);
-		virial_calc(ai,&force,&distance);
-		virial_calc(aj,&force,&distance); /* f and d signe switched */
-		v3_scale(&force,&distance,-f);
-		v3_add(&(aj->f),&(aj->f),&force);
-	}
-
-	return 0;
-}
-
-/* lennard jones potential & force for one sort of atoms */
- 
-int lennard_jones(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
-
-	t_lj_params *params;
-	t_3dvec force,distance;
-	double d,h1,h2;
-	double eps,sig6,sig12;
-
-	params=moldyn->pot2b_params;
-	eps=params->epsilon4;
-	sig6=params->sigma6;
-	sig12=params->sigma12;
-
-	if(ai<aj) return 0;
-
-	v3_sub(&distance,&(aj->r),&(ai->r));
-	if(bc) check_per_bound(moldyn,&distance);
-	d=v3_absolute_square(&distance);	/* 1/r^2 */
-	if(d<=moldyn->cutoff_square) {
-		d=1.0/d;			/* 1/r^2 */
-		h2=d*d; 			/* 1/r^4 */
-		h2*=d;	 			/* 1/r^6 */
-		h1=h2*h2; 			/* 1/r^12 */
-		moldyn->energy+=(eps*(sig12*h1-sig6*h2)-params->uc);
-		h2*=d;				/* 1/r^8 */
-		h1*=d;				/* 1/r^14 */
-		h2*=6*sig6;
-		h1*=12*sig12;
-		d=+h1-h2;
-		d*=eps;
-		v3_scale(&force,&distance,d);
-		v3_add(&(aj->f),&(aj->f),&force);
-		v3_scale(&force,&distance,-1.0*d); /* f = - grad E */
-		v3_add(&(ai->f),&(ai->f),&force);
-		virial_calc(ai,&force,&distance);
-		virial_calc(aj,&force,&distance); /* f and d signe switched */
-		moldyn->vt1-=v3_scalar_product(&force,&distance);
-	}
-
-	return 0;
-}
-
-/*
- * tersoff potential & force for 2 sorts of atoms
- */
-
-/* create mixed terms from parameters and set them */
-int tersoff_mult_complete_params(t_tersoff_mult_params *p) {
-
-	printf("[moldyn] tersoff parameter completion\n");
-	p->S2[0]=p->S[0]*p->S[0];
-	p->S2[1]=p->S[1]*p->S[1];
-	p->Smixed=sqrt(p->S[0]*p->S[1]);
-	p->S2mixed=p->Smixed*p->Smixed;
-	p->Rmixed=sqrt(p->R[0]*p->R[1]);
-	p->Amixed=sqrt(p->A[0]*p->A[1]);
-	p->Bmixed=sqrt(p->B[0]*p->B[1]);
-	p->lambda_m=0.5*(p->lambda[0]+p->lambda[1]);
-	p->mu_m=0.5*(p->mu[0]+p->mu[1]);
-
-	printf("[moldyn] tersoff mult parameter info:\n");
-	printf("  S (A)  | %f | %f | %f\n",p->S[0],p->S[1],p->Smixed);
-	printf("  R (A)  | %f | %f | %f\n",p->R[0],p->R[1],p->Rmixed);
-	printf("  A (eV) | %f | %f | %f\n",p->A[0]/EV,p->A[1]/EV,p->Amixed/EV);
-	printf("  B (eV) | %f | %f | %f\n",p->B[0]/EV,p->B[1]/EV,p->Bmixed/EV);
-	printf("  lambda | %f | %f | %f\n",p->lambda[0],p->lambda[1],
-	                                  p->lambda_m);
-	printf("  mu     | %f | %f | %f\n",p->mu[0],p->mu[1],p->mu_m);
-	printf("  beta   | %.10f | %.10f\n",p->beta[0],p->beta[1]);
-	printf("  n      | %f | %f\n",p->n[0],p->n[1]);
-	printf("  c      | %f | %f\n",p->c[0],p->c[1]);
-	printf("  d      | %f | %f\n",p->d[0],p->d[1]);
-	printf("  h      | %f | %f\n",p->h[0],p->h[1]);
-	printf("  chi    | %f \n",p->chi);
-
-	return 0;
-}
-
-/* tersoff 1 body part */
-int tersoff_mult_1bp(t_moldyn *moldyn,t_atom *ai) {
-
-	int brand;
-	t_tersoff_mult_params *params;
-	t_tersoff_exchange *exchange;
-	
-	brand=ai->brand;
-	params=moldyn->pot1b_params;
-	exchange=&(params->exchange);
-
-	/*
-	 * simple: point constant parameters only depending on atom i to
-	 *         their right values
-	 */
-
-	exchange->beta_i=&(params->beta[brand]);
-	exchange->n_i=&(params->n[brand]);
-	exchange->c_i=&(params->c[brand]);
-	exchange->d_i=&(params->d[brand]);
-	exchange->h_i=&(params->h[brand]);
-
-	exchange->betaini=pow(*(exchange->beta_i),*(exchange->n_i));
-	exchange->ci2=params->c[brand]*params->c[brand];
-	exchange->di2=params->d[brand]*params->d[brand];
-	exchange->ci2di2=exchange->ci2/exchange->di2;
-
-	return 0;
-}
-	
-/* tersoff 2 body part */
-int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
-
-	t_tersoff_mult_params *params;
-	t_tersoff_exchange *exchange;
-	t_3dvec dist_ij,force;
-	double d_ij,d_ij2;
-	double A,B,R,S,S2,lambda,mu;
-	double f_r,df_r;
-	double f_c,df_c;
-	int brand;
-	double s_r;
-	double arg;
-
-	params=moldyn->pot2b_params;
-	brand=aj->brand;
-	exchange=&(params->exchange);
-
-	/* clear 3bp and 2bp post run */
-	exchange->run3bp=0;
-	exchange->run2bp_post=0;
-
-	/* reset S > r > R mark */
-	exchange->d_ij_between_rs=0;
-	
-	/*
-	 * calc of 2bp contribution of V_ij and dV_ij/ji
-	 *
-	 * for Vij and dV_ij we need:
-	 * - f_c_ij, df_c_ij
-	 * - f_r_ij, df_r_ij
-	 *
-	 * for dV_ji we need:
-	 * - f_c_ji = f_c_ij, df_c_ji = df_c_ij
-	 * - f_r_ji = f_r_ij; df_r_ji = df_r_ij
-	 *
-	 */
-
-	/* constants */
-	if(brand==ai->brand) {
-		S=params->S[brand];
-		S2=params->S2[brand];
-		R=params->R[brand];
-		A=params->A[brand];
-		B=params->B[brand];
-		lambda=params->lambda[brand];
-		mu=params->mu[brand];
-		exchange->chi=1.0;
-	}
-	else {
-		S=params->Smixed;
-		S2=params->S2mixed;
-		R=params->Rmixed;
-		A=params->Amixed;
-		B=params->Bmixed;
-		lambda=params->lambda_m;
-		mu=params->mu_m;
-		params->exchange.chi=params->chi;
-	}
-
-	/* dist_ij, d_ij */
-	v3_sub(&dist_ij,&(aj->r),&(ai->r));
-	if(bc) check_per_bound(moldyn,&dist_ij);
-	d_ij2=v3_absolute_square(&dist_ij);
-
-	/* if d_ij2 > S2 => no force & potential energy contribution */
-	if(d_ij2>S2)
-		return 0;
-
-	/* now we will need the distance */
-	//d_ij=v3_norm(&dist_ij);
-	d_ij=sqrt(d_ij2);
-
-	/* save for use in 3bp */
-	exchange->d_ij=d_ij;
-	exchange->d_ij2=d_ij2;
-	exchange->dist_ij=dist_ij;
-
-	/* more constants */
-	exchange->beta_j=&(params->beta[brand]);
-	exchange->n_j=&(params->n[brand]);
-	exchange->c_j=&(params->c[brand]);
-	exchange->d_j=&(params->d[brand]);
-	exchange->h_j=&(params->h[brand]);
-	if(brand==ai->brand) {
-		exchange->betajnj=exchange->betaini;
-		exchange->cj2=exchange->ci2;
-		exchange->dj2=exchange->di2;
-		exchange->cj2dj2=exchange->ci2di2;
-	}
-	else {
-		exchange->betajnj=pow(*(exchange->beta_j),*(exchange->n_j));
-		exchange->cj2=params->c[brand]*params->c[brand];
-		exchange->dj2=params->d[brand]*params->d[brand];
-		exchange->cj2dj2=exchange->cj2/exchange->dj2;
-	}
-
-	/* f_r_ij = f_r_ji, df_r_ij = df_r_ji */
-	f_r=A*exp(-lambda*d_ij);
-	df_r=lambda*f_r/d_ij;
-
-	/* f_a, df_a calc (again, same for ij and ji) | save for later use! */
-	exchange->f_a=-B*exp(-mu*d_ij);
-	exchange->df_a=mu*exchange->f_a/d_ij;
-
-	/* f_c, df_c calc (again, same for ij and ji) */
-	if(d_ij<R) {
-		/* f_c = 1, df_c = 0 */
-		f_c=1.0;
-		df_c=0.0;
-		/* two body contribution (ij, ji) */
-		v3_scale(&force,&dist_ij,-df_r);
-	}
-	else {
-		s_r=S-R;
-		arg=M_PI*(d_ij-R)/s_r;
-		f_c=0.5+0.5*cos(arg);
-		df_c=0.5*sin(arg)*(M_PI/(s_r*d_ij));
-		/* two body contribution (ij, ji) */
-		v3_scale(&force,&dist_ij,-df_c*f_r-df_r*f_c);
-		/* tell 3bp that S > r > R */
-		exchange->d_ij_between_rs=1;
-	}
-
-	/* add forces of 2bp (ij, ji) contribution
-	 * dVij = dVji and we sum up both: no 1/2) */
-	v3_add(&(ai->f),&(ai->f),&force);
-
-	/* virial */
-	ai->virial.xx-=force.x*dist_ij.x;
-	ai->virial.yy-=force.y*dist_ij.y;
-	ai->virial.zz-=force.z*dist_ij.z;
-	ai->virial.xy-=force.x*dist_ij.y;
-	ai->virial.xz-=force.x*dist_ij.z;
-	ai->virial.yz-=force.y*dist_ij.z;
-
-#ifdef DEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVij, dVji (2bp) contrib:\n");
-	printf("%f | %f\n",force.x,ai->f.x);
-	printf("%f | %f\n",force.y,ai->f.y);
-	printf("%f | %f\n",force.z,ai->f.z);
-}
-#endif
-#ifdef VDEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVij, dVji (2bp) contrib:\n");
-	printf("%f | %f\n",force.x*dist_ij.x,ai->virial.xx);
-	printf("%f | %f\n",force.y*dist_ij.y,ai->virial.yy);
-	printf("%f | %f\n",force.z*dist_ij.z,ai->virial.zz);
-}
-#endif
-
-	/* energy 2bp contribution (ij, ji) is 0.5 f_r f_c ... */
-	moldyn->energy+=(0.5*f_r*f_c);
-
-	/* save for use in 3bp */
-	exchange->f_c=f_c;
-	exchange->df_c=df_c;
-
-	/* enable the run of 3bp function and 2bp post processing */
-	exchange->run3bp=1;
-	exchange->run2bp_post=1;
-
-	/* reset 3bp sums */
-	exchange->zeta_ij=0.0;
-	exchange->zeta_ji=0.0;
-	v3_zero(&(exchange->dzeta_ij));
-	v3_zero(&(exchange->dzeta_ji));
-
-	return 0;
-}
-
-/* tersoff 2 body post part */
-
-int tersoff_mult_post_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
-
-	/*
-	 * here we have to allow for the 3bp sums
-	 *
-	 * that is:
-	 * - zeta_ij, dzeta_ij
-	 * - zeta_ji, dzeta_ji
-	 *
-	 * to compute the 3bp contribution to:
-	 * - Vij, dVij
-	 * - dVji
-	 *
-	 */
-
-	t_tersoff_mult_params *params;
-	t_tersoff_exchange *exchange;
-
-	t_3dvec force,temp;
-	t_3dvec *dist_ij;
-	double b,db,tmp;
-	double f_c,df_c,f_a,df_a;
-	double chi,ni,betaini,nj,betajnj;
-	double zeta;
-
-	params=moldyn->pot2b_params;
-	exchange=&(params->exchange);
-
-	/* we do not run if f_c_ij was detected to be 0! */
-	if(!(exchange->run2bp_post))
-		return 0;
-
-	f_c=exchange->f_c;
-	df_c=exchange->df_c;
-	f_a=exchange->f_a;
-	df_a=exchange->df_a;
-	betaini=exchange->betaini;
-	betajnj=exchange->betajnj;
-	ni=*(exchange->n_i);
-	nj=*(exchange->n_j);
-	chi=exchange->chi;
-	dist_ij=&(exchange->dist_ij);
-	
-	/* Vij and dVij */
-	zeta=exchange->zeta_ij;
-	if(zeta==0.0) {
-		moldyn->debug++;		/* just for debugging ... */
-		b=chi;
-		v3_scale(&force,dist_ij,df_a*b*f_c);
-	}
-	else {
-		tmp=betaini*pow(zeta,ni-1.0);		/* beta^n * zeta^n-1 */
-		b=(1+zeta*tmp);				/* 1 + beta^n zeta^n */
-		db=chi*pow(b,-1.0/(2*ni)-1);		/* x(...)^(-1/2n - 1) */
-		b=db*b;					/* b_ij */
-		db*=-0.5*tmp;				/* db_ij */
-		v3_scale(&force,&(exchange->dzeta_ij),f_a*db);
-		v3_scale(&temp,dist_ij,df_a*b);
-		v3_add(&force,&force,&temp);
-		v3_scale(&force,&force,f_c);
-	}
-	v3_scale(&temp,dist_ij,df_c*b*f_a);
-	v3_add(&force,&force,&temp);
-	v3_scale(&force,&force,-0.5);
-
-	/* add force */
-	v3_add(&(ai->f),&(ai->f),&force);
-
-	/* virial */
-	ai->virial.xx-=force.x*dist_ij->x;
-	ai->virial.yy-=force.y*dist_ij->y;
-	ai->virial.zz-=force.z*dist_ij->z;
-	ai->virial.xy-=force.x*dist_ij->y;
-	ai->virial.xz-=force.x*dist_ij->z;
-	ai->virial.yz-=force.y*dist_ij->z;
-
-#ifdef DEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVij (3bp) contrib:\n");
-	printf("%f | %f\n",force.x,ai->f.x);
-	printf("%f | %f\n",force.y,ai->f.y);
-	printf("%f | %f\n",force.z,ai->f.z);
-}
-#endif
-#ifdef VDEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVij (3bp) contrib:\n");
-	printf("%f | %f\n",force.x*dist_ij->x,ai->virial.xx);
-	printf("%f | %f\n",force.y*dist_ij->y,ai->virial.yy);
-	printf("%f | %f\n",force.z*dist_ij->z,ai->virial.zz);
-}
-#endif
-
-	/* add energy of 3bp sum */
-	moldyn->energy+=(0.5*f_c*b*f_a);
-
-	/* dVji */
-	zeta=exchange->zeta_ji;
-	if(zeta==0.0) {
-		moldyn->debug++;
-		b=chi;
-		v3_scale(&force,dist_ij,df_a*b*f_c);
-	}
-	else {
-		tmp=betajnj*pow(zeta,nj-1.0);		/* beta^n * zeta^n-1 */
-		b=(1+zeta*tmp);				/* 1 + beta^n zeta^n */
-		db=chi*pow(b,-1.0/(2*nj)-1);		/* x(...)^(-1/2n - 1) */
-		b=db*b;					/* b_ij */
-		db*=-0.5*tmp;				/* db_ij */
-		v3_scale(&force,&(exchange->dzeta_ji),f_a*db);
-		v3_scale(&temp,dist_ij,df_a*b);
-		v3_add(&force,&force,&temp);
-		v3_scale(&force,&force,f_c);
-	}
-	v3_scale(&temp,dist_ij,df_c*b*f_a);
-	v3_add(&force,&force,&temp);
-	v3_scale(&force,&force,-0.5);
-
-	/* add force */
-	v3_add(&(ai->f),&(ai->f),&force);
-
-	/* virial - plus sign, as dist_ij = - dist_ji - (really??) */
-// TEST ... with a minus instead
-	ai->virial.xx-=force.x*dist_ij->x;
-	ai->virial.yy-=force.y*dist_ij->y;
-	ai->virial.zz-=force.z*dist_ij->z;
-	ai->virial.xy-=force.x*dist_ij->y;
-	ai->virial.xz-=force.x*dist_ij->z;
-	ai->virial.yz-=force.y*dist_ij->z;
-
-#ifdef DEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVji (3bp) contrib:\n");
-	printf("%f | %f\n",force.x,ai->f.x);
-	printf("%f | %f\n",force.y,ai->f.y);
-	printf("%f | %f\n",force.z,ai->f.z);
-}
-#endif
-#ifdef VDEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVji (3bp) contrib:\n");
-	printf("%f | %f\n",force.x*dist_ij->x,ai->virial.xx);
-	printf("%f | %f\n",force.y*dist_ij->y,ai->virial.yy);
-	printf("%f | %f\n",force.z*dist_ij->z,ai->virial.zz);
-}
-#endif
-
-	return 0;
-}
-
-/* tersoff 3 body part */
-
-int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
-
-	t_tersoff_mult_params *params;
-	t_tersoff_exchange *exchange;
-	t_3dvec dist_ij,dist_ik,dist_jk;
-	t_3dvec temp1,temp2;
-	t_3dvec *dzeta;
-	double R,S,S2,s_r;
-	double B,mu;
-	double d_ij,d_ik,d_jk,d_ij2,d_ik2,d_jk2;
-	double rr,dd;
-	double f_c,df_c;
-	double f_c_ik,df_c_ik,arg;
-	double f_c_jk;
-	double n,c,d,h;
-	double c2,d2,c2d2;
-	double cos_theta,d_costheta1,d_costheta2;
-	double h_cos,d2_h_cos2;
-	double frac,g,zeta,chi;
-	double tmp;
-	int brand;
-
-	params=moldyn->pot3b_params;
-	exchange=&(params->exchange);
-
-	if(!(exchange->run3bp))
-		return 0;
-
-	/*
-	 * calc of 3bp contribution of V_ij and dV_ij/ji/jk &
-	 * 2bp contribution of dV_jk
-	 *
-	 * for Vij and dV_ij we still need:
-	 * - b_ij, db_ij (zeta_ij)
-	 *   - f_c_ik, df_c_ik, constants_i, cos_theta_ijk, d_costheta_ijk
-	 *
-	 * for dV_ji we still need:
-	 * - b_ji, db_ji (zeta_ji)
-	 *   - f_c_jk, d_c_jk, constants_j, cos_theta_jik, d_costheta_jik
-	 *
-	 * for dV_jk we need:
-	 * - f_c_jk
-	 * - f_a_jk
-	 * - db_jk (zeta_jk)
-	 *   - f_c_ji, df_c_ji, constants_j, cos_theta_jki, d_costheta_jki
-	 *
-	 */
-
-	/*
-	 * get exchange data 
-	 */
-
-	/* dist_ij, d_ij - this is < S_ij ! */
-	dist_ij=exchange->dist_ij;
-	d_ij=exchange->d_ij;
-	d_ij2=exchange->d_ij2;
-
-	/* f_c_ij, df_c_ij (same for ji) */
-	f_c=exchange->f_c;
-	df_c=exchange->df_c;
-
-	/*
-	 * calculate unknown values now ...
-	 */
-
-	/* V_ij and dV_ij stuff (in b_ij there is f_c_ik) */
-
-	/* dist_ik, d_ik */
-	v3_sub(&dist_ik,&(ak->r),&(ai->r));
-	if(bc) check_per_bound(moldyn,&dist_ik);
-	d_ik2=v3_absolute_square(&dist_ik);
-
-	/* ik constants */
-	brand=ai->brand;
-	if(brand==ak->brand) {
-		R=params->R[brand];
-		S=params->S[brand];
-		S2=params->S2[brand];
-	}
-	else {
-		R=params->Rmixed;
-		S=params->Smixed;
-		S2=params->S2mixed;
-	}
-
-	/* zeta_ij/dzeta_ij contribution only for d_ik < S */
-	if(d_ik2<S2) {
-
-		/* now we need d_ik */
-		d_ik=sqrt(d_ik2);
-
-		/* get constants_i from exchange data */
-		n=*(exchange->n_i);
-		c=*(exchange->c_i);
-		d=*(exchange->d_i);
-		h=*(exchange->h_i);
-		c2=exchange->ci2;
-		d2=exchange->di2;
-		c2d2=exchange->ci2di2;
-
-		/* cosine of theta_ijk by scalaproduct */
-		rr=v3_scalar_product(&dist_ij,&dist_ik);
-		dd=d_ij*d_ik;
-		cos_theta=rr/dd;
-
-		/* d_costheta */
-		tmp=1.0/dd;
-		d_costheta1=cos_theta/d_ij2-tmp;
-		d_costheta2=cos_theta/d_ik2-tmp;
-
-		/* some usefull values */
-		h_cos=(h-cos_theta);
-		d2_h_cos2=d2+(h_cos*h_cos);
-		frac=c2/(d2_h_cos2);
-
-		/* g(cos_theta) */
-		g=1.0+c2d2-frac;
-
-		/* d_costheta_ij and dg(cos_theta) - needed in any case! */
-		v3_scale(&temp1,&dist_ij,d_costheta1);
-		v3_scale(&temp2,&dist_ik,d_costheta2);
-		v3_add(&temp1,&temp1,&temp2);
-		v3_scale(&temp1,&temp1,-2.0*frac*h_cos/d2_h_cos2); /* dg */
-
-		/* f_c_ik & df_c_ik + {d,}zeta contribution */
-		dzeta=&(exchange->dzeta_ij);
-		if(d_ik<R) {
-			/* {d,}f_c_ik */
-			// => f_c_ik=1.0;
-			// => df_c_ik=0.0; of course we do not set this!
-
-			/* zeta_ij */
-			exchange->zeta_ij+=g;
-
-			/* dzeta_ij */
-			v3_add(dzeta,dzeta,&temp1);
-		}
-		else {
-			/* {d,}f_c_ik */
-			s_r=S-R;
-			arg=M_PI*(d_ik-R)/s_r;
-			f_c_ik=0.5+0.5*cos(arg);
-			df_c_ik=0.5*sin(arg)*(M_PI/(s_r*d_ik));
-
-			/* zeta_ij */
-			exchange->zeta_ij+=f_c_ik*g;
-
-			/* dzeta_ij */
-			v3_scale(&temp1,&temp1,f_c_ik);
-			v3_scale(&temp2,&dist_ik,g*df_c_ik);
-			v3_add(&temp1,&temp1,&temp2);
-			v3_add(dzeta,dzeta,&temp1);
-		}
-	}
-
-	/* dV_ji stuff (in b_ji there is f_c_jk) + dV_jk stuff! */
-
-	/* dist_jk, d_jk */
-	v3_sub(&dist_jk,&(ak->r),&(aj->r));
-	if(bc) check_per_bound(moldyn,&dist_jk);
-	d_jk2=v3_absolute_square(&dist_jk);
-
-	/* jk constants */
-	brand=aj->brand;
-	if(brand==ak->brand) {
-		R=params->R[brand];
-		S=params->S[brand];
-		S2=params->S2[brand];
-		B=params->B[brand];
-		mu=params->mu[brand];
-		chi=1.0;
-	}
-	else {
-		R=params->Rmixed;
-		S=params->Smixed;
-		S2=params->S2mixed;
-		B=params->Bmixed;
-		mu=params->mu_m;
-		chi=params->chi;
-	}
-
-	/* zeta_ji/dzeta_ji contribution only for d_jk < S_jk */
-	if(d_jk2<S2) {
-
-		/* now we need d_ik */
-		d_jk=sqrt(d_jk2);
-
-		/* constants_j from exchange data */
-		n=*(exchange->n_j);
-		c=*(exchange->c_j);
-		d=*(exchange->d_j);
-		h=*(exchange->h_j);
-		c2=exchange->cj2;
-		d2=exchange->dj2;
-		c2d2=exchange->cj2dj2;
-
-		/* cosine of theta_jik by scalaproduct */
-		rr=-v3_scalar_product(&dist_ij,&dist_jk); /* -1, as ij -> ji */
-		dd=d_ij*d_jk;
-		cos_theta=rr/dd;
-
-		/* d_costheta */
-		d_costheta1=1.0/dd;
-		d_costheta2=cos_theta/d_ij2;
-
-		/* some usefull values */
-		h_cos=(h-cos_theta);
-		d2_h_cos2=d2+(h_cos*h_cos);
-		frac=c2/(d2_h_cos2);
-
-		/* g(cos_theta) */
-		g=1.0+c2d2-frac;
-
-		/* d_costheta_jik and dg(cos_theta) - needed in any case! */
-		v3_scale(&temp1,&dist_jk,d_costheta1);
-		v3_scale(&temp2,&dist_ij,-d_costheta2); /* ji -> ij => -1 */
-		//v3_add(&temp1,&temp1,&temp2);
-		v3_sub(&temp1,&temp1,&temp2); /* there is a minus! */
-		v3_scale(&temp1,&temp1,-2.0*frac*h_cos/d2_h_cos2); /* dg */
-
-		/* store dg in temp2 and use it for dVjk later */
-		v3_copy(&temp2,&temp1);
-
-		/* f_c_jk + {d,}zeta contribution (df_c_jk = 0) */
-		dzeta=&(exchange->dzeta_ji);
-		if(d_jk<R) {
-			/* f_c_jk */
-			f_c_jk=1.0;
-
-			/* zeta_ji */
-			exchange->zeta_ji+=g;
-
-			/* dzeta_ji */
-			v3_add(dzeta,dzeta,&temp1);
-		}
-		else {
-			/* f_c_jk */
-			s_r=S-R;
-			arg=M_PI*(d_jk-R)/s_r;
-			f_c_jk=0.5+0.5*cos(arg);
-
-			/* zeta_ji */
-			exchange->zeta_ji+=f_c_jk*g;
-
-			/* dzeta_ji */
-			v3_scale(&temp1,&temp1,f_c_jk);
-			v3_add(dzeta,dzeta,&temp1);
-		}
-
-		/* dV_jk stuff | add force contribution on atom i immediately */
-		if(exchange->d_ij_between_rs) {
-			zeta=f_c*g;
-			v3_scale(&temp1,&temp2,f_c);
-			v3_scale(&temp2,&dist_ij,df_c*g);
-			v3_add(&temp2,&temp2,&temp1); /* -> dzeta_jk in temp2 */
-		}
-		else {
-			zeta=g;
-			// dzeta_jk is simply dg, which is stored in temp2
-		}
-		/* betajnj * zeta_jk ^ nj-1 */
-		tmp=exchange->betajnj*pow(zeta,(n-1.0));
-		tmp=-chi/2.0*pow((1+tmp*zeta),(-1.0/(2.0*n)-1))*tmp;
-		v3_scale(&temp2,&temp2,tmp*B*exp(-mu*d_jk)*f_c_jk*0.5);
-		v3_add(&(ai->f),&(ai->f),&temp2); /* -1 skipped in f_a calc ^ */
-		                                  /* scaled with 0.5 ^ */
-
-		/* virial */
-		ai->virial.xx-=temp2.x*dist_jk.x;
-		ai->virial.yy-=temp2.y*dist_jk.y;
-		ai->virial.zz-=temp2.z*dist_jk.z;
-		ai->virial.xy-=temp2.x*dist_jk.y;
-		ai->virial.xz-=temp2.x*dist_jk.z;
-		ai->virial.yz-=temp2.y*dist_jk.z;
-
-#ifdef DEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVjk (3bp) contrib:\n");
-	printf("%f | %f\n",temp2.x,ai->f.x);
-	printf("%f | %f\n",temp2.y,ai->f.y);
-	printf("%f | %f\n",temp2.z,ai->f.z);
-}
-#endif
-#ifdef VDEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVjk (3bp) contrib:\n");
-	printf("%f | %f\n",temp2.x*dist_jk.x,ai->virial.xx);
-	printf("%f | %f\n",temp2.y*dist_jk.y,ai->virial.yy);
-	printf("%f | %f\n",temp2.z*dist_jk.z,ai->virial.zz);
-}
-#endif
-
-	}
-
-	return 0;
-}
-
-
 /*
  * debugging / critical check functions
  */
@@ -2255,3 +1809,133 @@ int moldyn_bc_check(t_moldyn *moldyn) {
 
 	return 0;
 }
+
+/*
+ * postprocessing functions
+ */
+
+int get_line(int fd,char *line,int max) {
+
+	int count,ret;
+
+	count=0;
+
+	while(1) {
+		if(count==max) return count;
+		ret=read(fd,line+count,1);
+		if(ret<=0) return ret;
+		if(line[count]=='\n') {
+			line[count]='\0';
+			return count+1;
+		}
+		count+=1;
+	}
+}
+
+int calc_fluctuations(double start,double end,t_moldyn *moldyn) {
+
+	int fd;
+	int count,ret;
+	double time,pot,kin,tot;
+	double p_sum,k_sum,t_sum;
+	char buf[64];
+	char file[128+7];
+
+	printf("[moldyn] calculating energy fluctuations [eV]:\n");
+
+	snprintf(file,128+7,"%s/energy",moldyn->vlsdir);
+	fd=open(file,O_RDONLY);
+	if(fd<0) {
+		perror("[moldyn] post proc energy open");
+		return fd;
+	}
+
+	/* first calc the averages */
+	p_sum=0.0;
+	k_sum=0.0;
+	t_sum=0.0;
+	count=0;
+	while(1) {
+		ret=get_line(fd,buf,63);
+		if(ret<=0) break;
+		if(buf[0]=='#') continue;
+		sscanf(buf,"%lf %lf %lf %lf",&time,&kin,&pot,&tot);
+		if(time<start) continue;
+		if(time>end) break;
+		p_sum+=pot;
+		k_sum+=kin;
+		t_sum+=tot;
+		count+=1;
+	}
+
+	moldyn->p_m=p_sum/count;
+	moldyn->k_m=k_sum/count;
+	moldyn->t_m=t_sum/count;
+
+	/* mean square fluctuations */
+	if(lseek(fd,SEEK_SET,0)<0) {
+		perror("[moldyn] lseek");
+		return -1;
+	}
+	count=0;
+	p_sum=0.0;
+	k_sum=0.0;
+	t_sum=0.0;
+	while(1) {
+		ret=get_line(fd,buf,63);
+		if(ret<=0) break;
+		if(buf[0]=='#') continue;
+		sscanf(buf,"%lf %lf %lf %lf",&time,&kin,&pot,&tot);
+		if(time<start) continue;
+		if(time>end) break;
+		k_sum+=((kin-moldyn->k_m)*(kin-moldyn->k_m));
+		p_sum+=((pot-moldyn->p_m)*(pot-moldyn->p_m));
+		t_sum+=((tot-moldyn->t_m)*(tot-moldyn->t_m));
+		count+=1;
+	}
+
+	moldyn->dp2_m=p_sum/count;
+	moldyn->dk2_m=k_sum/count;
+	moldyn->dt2_m=t_sum/count;
+
+	printf("  averages   : %f %f %f\n",moldyn->k_m,
+	                                moldyn->p_m,
+	                                moldyn->t_m);
+	printf("  mean square: %f %f %f\n",moldyn->dk2_m,
+	                                   moldyn->dp2_m,
+	                                   moldyn->dt2_m);
+
+	close(fd);
+
+	return 0;
+}
+
+int get_heat_capacity(t_moldyn *moldyn) {
+
+	double temp2,mass,ighc;
+	int i;
+
+	/* (temperature average)^2 */
+	temp2=2.0*moldyn->k_m*EV/(3.0*K_BOLTZMANN);
+	printf("[moldyn] specific heat capacity for T=%f K [J/(kg K)]\n",temp2);
+	temp2*=temp2;
+
+	/* total mass */
+	mass=0.0;
+	for(i=0;i<moldyn->count;i++)
+		mass+=moldyn->atom[i].mass;
+
+	/* ideal gas contribution */
+	ighc=3.0*moldyn->count*K_BOLTZMANN/2.0;
+	printf("  ideal gas contribution: %f\n",ighc/mass*KILOGRAM/JOULE);
+
+	moldyn->c_v_nvt=moldyn->dp2_m*moldyn->count*moldyn->count*EV/(K_BOLTZMANN*temp2)+ighc;
+	moldyn->c_v_nvt/=mass;
+	moldyn->c_v_nve=ighc/(1.0-(moldyn->dp2_m*moldyn->count*moldyn->count*EV/(ighc*K_BOLTZMANN*temp2)));
+	moldyn->c_v_nve/=mass;
+
+	printf("  NVE: %f\n",moldyn->c_v_nve*KILOGRAM/JOULE);
+	printf("  NVT: %f\n",moldyn->c_v_nvt*KILOGRAM/JOULE);
+
+	return 0;
+}