X-Git-Url: https://www.hackdaworld.org/gitweb/?a=blobdiff_plain;f=moldyn.c;h=a9785413ab55eec8ef5c4f6ba46e7a6f1f8b3726;hb=56fe12b9eabe0cfa493e2f1b1d0d7d219ae8705b;hp=c0b99eb70f72e6e103fecaa5157ce5679573e4b4;hpb=11bf064825efc474fa93c7270870856769a63e84;p=physik%2Fposic.git

diff --git a/moldyn.c b/moldyn.c
index c0b99eb..a978541 100644
--- a/moldyn.c
+++ b/moldyn.c
@@ -41,6 +41,7 @@ int moldyn_init(t_moldyn *moldyn,int argc,char **argv) {
 
 int moldyn_shutdown(t_moldyn *moldyn) {
 
+	moldyn_log_shutdown(moldyn);
 	link_cell_shutdown(moldyn);
 	moldyn_log_shutdown(moldyn);
 	rand_close(&(moldyn->random));
@@ -51,12 +52,12 @@ int moldyn_shutdown(t_moldyn *moldyn) {
 
 int set_int_alg(t_moldyn *moldyn,u8 algo) {
 
-	switch(alg) {
-		case 'MOLDYN_INTEGRATE_VERLET':
+	switch(algo) {
+		case MOLDYN_INTEGRATE_VERLET:
 			moldyn->integrate=velocity_verlet;
 			break;
 		default:
-			printf("unknown integration algorithm: %02x\",alg);
+			printf("unknown integration algorithm: %02x\n",algo);
 			return -1;
 	}
 
@@ -106,25 +107,26 @@ int set_pbc(t_moldyn *moldyn,u8 x,u8 y,u8 z) {
 	return 0;
 }
 
-int set_potential(t_moldyn *moldyn,u8 type,(int *)(func),void *params) {
+int set_potential1b(t_moldyn *moldyn,pf_func1b func,void *params) {
 
-	switch(type) {
-		case MOLDYN_1BP:
-			moldyn->pf_func1b=func;
-			moldyn->pot1b_params=params;
-			break;
-		case MOLDYN_2BP:
-			moldyn->pf_func2b=func;
-			moldyn->pot2b_params=params;
-			break;
-		case MOLDYN_3BP:
-			moldyn->pf_func3b=func;
-			moldyn->pot3b_params=params;
-			break;
-		default:
-			printf("unknown potential type: %02x\n",type);
-			return -1;
-	}
+	moldyn->func1b=func;
+	moldyn->pot1b_params=params;
+
+	return 0;
+}
+
+int set_potential2b(t_moldyn *moldyn,pf_func2b func,void *params) {
+
+	moldyn->func2b=func;
+	moldyn->pot2b_params=params;
+
+	return 0;
+}
+
+int set_potential3b(t_moldyn *moldyn,pf_func3b func,void *params) {
+
+	moldyn->func3b=func;
+	moldyn->pot3b_params=params;
 
 	return 0;
 }
@@ -139,7 +141,7 @@ int moldyn_set_log(t_moldyn *moldyn,u8 type,char *fb,int timer) {
 				perror("[moldyn] efd open");
 				return moldyn->efd;
 			}
-			dprintf("# moldyn total energy log file\n");
+			dprintf(moldyn->efd,"# total energy log file\n");
 			break;
 		case LOG_TOTAL_MOMENTUM:
 			moldyn->mwrite=timer;
@@ -148,14 +150,14 @@ int moldyn_set_log(t_moldyn *moldyn,u8 type,char *fb,int timer) {
 				perror("[moldyn] mfd open");
 				return moldyn->mfd;
 			}
-			dprintf("# moldyn total momentum log file\n");
+			dprintf(moldyn->efd,"# total momentum log file\n");
 			break;
 		case SAVE_STEP:
 			moldyn->swrite=timer;
 			strncpy(moldyn->sfb,fb,63);
 			break;
 		case VISUAL_STEP:
-			moldyn->mwrite=timer;
+			moldyn->vwrite=timer;
 			strncpy(moldyn->vfb,fb,63);
 			visual_init(&(moldyn->vis),fb);
 			break;
@@ -233,7 +235,7 @@ int create_lattice(t_moldyn *moldyn,u8 type,double lc,int element,double mass,
 }
 
 int add_atom(t_moldyn *moldyn,int element,double mass,u8 bnum,u8 attr,
-             t_3dvec r,t_3dvec v) {
+             t_3dvec *r,t_3dvec *v) {
 
 	t_atom *atom;
 	void *ptr;
@@ -247,13 +249,15 @@ int add_atom(t_moldyn *moldyn,int element,double mass,u8 bnum,u8 attr,
 		perror("[moldyn] realloc (add atom)");
 		return -1;
 	}
-	
-	atom=ptr;
-	atom->r=r;
-	atom->v=v;
-	atom->element=element;
-	atom->bnum=bnum;
-	atom->attr=attr;
+	moldyn->atom=ptr;
+
+	atom=moldyn->atom;
+	atom[count-1].r=*r;
+	atom[count-1].v=*v;
+	atom[count-1].element=element;
+	atom[count-1].mass=mass;
+	atom[count-1].bnum=bnum;
+	atom[count-1].attr=attr;
 
 	return 0;
 }
@@ -324,6 +328,12 @@ int scale_velocity(t_moldyn *moldyn) {
 	/*
 	 * - velocity scaling (E = 3/2 N k T), E: kinetic energy
 	 */
+
+	if(moldyn->t==0.0) {
+		printf("[moldyn] no velocity scaling for T = 0 K\n");
+		return -1;
+	}
+
 	e=0.0;
 	for(i=0;i<moldyn->count;i++)
 		e+=0.5*atom[i].mass*v3_absolute_square(&(atom[i].v));
@@ -353,9 +363,14 @@ double get_e_pot(t_moldyn *moldyn) {
 	return moldyn->energy;
 }
 
+double update_e_kin(t_moldyn *moldyn) {
+
+	return(get_e_kin(moldyn));
+}
+
 double get_total_energy(t_moldyn *moldyn) {
 
-	return(get_e_kin(moldyn)+get_e_pot(moldyn));
+	return(moldyn->ekin+moldyn->energy);
 }
 
 t_3dvec get_total_p(t_moldyn *moldyn) {
@@ -367,7 +382,7 @@ t_3dvec get_total_p(t_moldyn *moldyn) {
 	atom=moldyn->atom;
 
 	v3_zero(&p_total);
-	for(i=0;i<count;i++) {
+	for(i=0;i<moldyn->count;i++) {
 		v3_scale(&p,&(atom[i].v),atom[i].mass);
 		v3_add(&p_total,&p_total,&p);
 	}
@@ -375,15 +390,19 @@ t_3dvec get_total_p(t_moldyn *moldyn) {
 	return p_total;
 }
 
-double estimate_time_step(t_moldyn *moldyn,double nn_dist,double t) {
+double estimate_time_step(t_moldyn *moldyn,double nn_dist) {
 
 	double tau;
 
-	tau=0.05*nn_dist/(sqrt(3.0*K_BOLTZMANN*t/moldyn->atom[0].mass));
-	tau*=1.0E-9;
-	if(tau<moldyn->tau)
-		printf("[moldyn] warning: time step  (%f > %.15f)\n",
-		       moldyn->tau,tau);
+	/* nn_dist is the nearest neighbour distance */
+
+	if(moldyn->t==5.0) {
+		printf("[moldyn] i do not estimate timesteps below %f K!\n",
+		       MOLDYN_CRITICAL_EST_TEMP);
+		return 23.42;
+	}
+
+	tau=(0.05*nn_dist*moldyn->atom[0].mass)/sqrt(3.0*K_BOLTZMANN*moldyn->t);
 
 	return tau;	
 }
@@ -398,11 +417,11 @@ int link_cell_init(t_moldyn *moldyn) {
 
 	t_linkcell *lc;
 	int i;
+	int fd;
 
-	lc=&(moldyn->lc);
+	fd=open("/dev/null",O_WRONLY);
 
-	/* list log fd */
-	lc->listfd=open("/dev/null",O_WRONLY);
+	lc=&(moldyn->lc);
 
 	/* partitioning the md cell */
 	lc->nx=moldyn->dim.x/moldyn->cutoff;
@@ -415,11 +434,11 @@ int link_cell_init(t_moldyn *moldyn) {
 	lc->cells=lc->nx*lc->ny*lc->nz;
 	lc->subcell=malloc(lc->cells*sizeof(t_list));
 
-	printf("initializing linked cells (%d)\n",lc->cells);
+	printf("[moldyn] initializing linked cells (%d)\n",lc->cells);
 
 	for(i=0;i<lc->cells;i++)
 		//list_init(&(lc->subcell[i]),1);
-		list_init(&(lc->subcell[i]));
+		list_init(&(lc->subcell[i]),fd);
 
  	link_cell_update(moldyn);
 	
@@ -443,7 +462,7 @@ int link_cell_update(t_moldyn *moldyn) {
 	for(i=0;i<lc->cells;i++)
 		list_destroy(&(moldyn->lc.subcell[i]));
 	
-	for(count=0;count<moedyn->count;count++) {
+	for(count=0;count<moldyn->count;count++) {
 		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;
@@ -522,8 +541,6 @@ int link_cell_shutdown(t_moldyn *moldyn) {
 	for(i=0;i<lc->nx*lc->ny*lc->nz;i++)
 		list_shutdown(&(moldyn->lc.subcell[i]));
 
-	if(lc->listfd) close(lc->listfd);
-
 	return 0;
 }
 
@@ -533,7 +550,7 @@ int moldyn_add_schedule(t_moldyn *moldyn,int runs,double tau) {
 	void *ptr;
 	t_moldyn_schedule *schedule;
 
-	schedule=moldyn->schedule;
+	schedule=&(moldyn->schedule);
 	count=++(schedule->content_count);
 
 	ptr=realloc(moldyn->schedule.runs,count*sizeof(int));
@@ -541,6 +558,7 @@ int moldyn_add_schedule(t_moldyn *moldyn,int runs,double tau) {
 		perror("[moldyn] realloc (runs)");
 		return -1;
 	}
+	moldyn->schedule.runs=ptr;
 	moldyn->schedule.runs[count-1]=runs;
 
 	ptr=realloc(schedule->tau,count*sizeof(double));
@@ -548,6 +566,7 @@ int moldyn_add_schedule(t_moldyn *moldyn,int runs,double tau) {
 		perror("[moldyn] realloc (tau)");
 		return -1;
 	}
+	moldyn->schedule.tau=ptr;
 	moldyn->schedule.tau[count-1]=tau;
 
 	return 0;
@@ -572,12 +591,17 @@ int moldyn_set_schedule_hook(t_moldyn *moldyn,void *hook,void *hook_params) {
 int moldyn_integrate(t_moldyn *moldyn) {
 
 	int i,sched;
-	unsigned int e,m,s,d,v;
+	unsigned int e,m,s,v;
 	t_3dvec p;
+	t_moldyn_schedule *schedule;
+	t_atom *atom;
 
 	int fd;
 	char fb[128];
 
+	schedule=&(moldyn->schedule);
+	atom=moldyn->atom;
+
 	/* initialize linked cell method */
 	link_cell_init(moldyn);
 
@@ -585,27 +609,28 @@ int moldyn_integrate(t_moldyn *moldyn) {
 	e=moldyn->ewrite;
 	m=moldyn->mwrite;
 	s=moldyn->swrite;
-	d=moldyn->dwrite;
 	v=moldyn->vwrite;
 
-	if(!(moldyn->lvstat&MOLDYN_LVSTAT_INITIALIZED)) {
-		printf("[moldyn] warning, lv system not initialized\n");
-		return -1;
-	}
-
 	/* sqaure of some variables */
 	moldyn->tau_square=moldyn->tau*moldyn->tau;
 	moldyn->cutoff_square=moldyn->cutoff*moldyn->cutoff;
 
 	/* calculate initial forces */
-	moldyn->potential_force_function(moldyn);
+	potential_force_calc(moldyn);
+
+	/* accuracy check */
+	ds=0.5*moldyn->tau_square*v3_norm(&(atom[0].f))/atom[0].mass;
+	if(ds>moldyn->lc.
+
+	/* zero absolute time */
+	moldyn->time=0.0;
 
 	for(sched=0;sched<moldyn->schedule.content_count;sched++) {
 
-		/* setting amont of runs and finite time step size */
+		/* setting amount of runs and finite time step size */
 		moldyn->tau=schedule->tau[sched];
 		moldyn->tau_square=moldyn->tau*moldyn->tau;
-		moldyn->timesteps=schedule->runs[sched];
+		moldyn->time_steps=schedule->runs[sched];
 
 	/* integration according to schedule */
 
@@ -614,18 +639,23 @@ int moldyn_integrate(t_moldyn *moldyn) {
 		/* integration step */
 		moldyn->integrate(moldyn);
 
+		/* increase absolute time */
+		moldyn->time+=moldyn->tau;
+
 		/* check for log & visualization */
 		if(e) {
 			if(!(i%e))
 				dprintf(moldyn->efd,
-				        "%.15f %.45f\n",i*moldyn->tau,
+				        "%.15f %.45f %.45f %.45f\n",
+				        moldyn->time,update_e_kin(moldyn),
+				        moldyn->energy,
 				        get_total_energy(moldyn));
 		}
 		if(m) {
 			if(!(i%m)) {
-				p=get_total_p(moldyn->atom,moldyn->count);
+				p=get_total_p(moldyn);
 				dprintf(moldyn->mfd,
-				        "%.15f %.45f\n",i*moldyn->tau,
+				        "%.15f %.45f\n",moldyn->time,
 				        v3_norm(&p));
 			}
 		}
@@ -645,18 +675,21 @@ int moldyn_integrate(t_moldyn *moldyn) {
 		}
 		if(v) {
 			if(!(i%v)) {
-				visual_atoms(moldyn->visual,i*moldyn->tau,
+				visual_atoms(&(moldyn->vis),moldyn->time,
 				             moldyn->atom,moldyn->count);
-				printf("\rsteps: %d",i);
+				printf("\rsched: %d, steps: %d",sched,i);
 				fflush(stdout);
 			}
 		}
+
 	}
 
 		/* check for hooks */
 		if(schedule->hook)
 			schedule->hook(moldyn,schedule->hook_params);
 
+	}
+
 	return 0;
 }
 
@@ -680,7 +713,7 @@ int velocity_verlet(t_moldyn *moldyn) {
 		v3_add(&(atom[i].r),&(atom[i].r),&delta);
 		v3_scale(&delta,&(atom[i].f),0.5*tau_square/atom[i].mass);
 		v3_add(&(atom[i].r),&(atom[i].r),&delta);
-		v3_per_bound(&(atom[i].r),&(moldyn->dim));
+		check_per_bound(moldyn,&(atom[i].r));
 
 		/* velocities */
 		v3_scale(&delta,&(atom[i].f),0.5*tau/atom[i].mass);
@@ -688,15 +721,11 @@ int velocity_verlet(t_moldyn *moldyn) {
 	}
 
 	/* neighbour list update */
-printf("list update ...\n");
 	link_cell_update(moldyn);
-printf("done\n");
 
 	/* forces depending on chosen potential */
-printf("calc potential/force ...\n");
 	potential_force_calc(moldyn);
 	//moldyn->potential_force_function(moldyn);
-printf("done\n");
 
 	for(i=0;i<count;i++) {
 		/* again velocities */
@@ -718,13 +747,12 @@ printf("done\n");
 
 int potential_force_calc(t_moldyn *moldyn) {
 
-	int i,count;
-	t_atom *atom;
+	int i,j,k,count;
+	t_atom *atom,*btom,*ktom;
 	t_linkcell *lc;
 	t_list neighbour[27];
-	t_list *this;
-	double u;
-	u8 bc,bc3;
+	t_list *this,*thisk,*neighbourk;
+	u8 bc,bck;
 	int countn,dnlc;
 
 	count=moldyn->count;
@@ -741,11 +769,11 @@ int potential_force_calc(t_moldyn *moldyn) {
 
 		/* single particle potential/force */
 		if(atom[i].attr&ATOM_ATTR_1BP)
-			moldyn->pf_func1b(moldyn,&(atom[i]));
+			moldyn->func1b(moldyn,&(atom[i]));
 
 		/* 2 body pair potential/force */
 		if(atom[i].attr&(ATOM_ATTR_2BP|ATOM_ATTR_3BP)) {
-		
+	
 			link_cell_neighbour_index(moldyn,
 				(atom[i].r.x+moldyn->dim.x/2)/lc->x,
 				(atom[i].r.y+moldyn->dim.y/2)/lc->y,
@@ -773,10 +801,10 @@ int potential_force_calc(t_moldyn *moldyn) {
 
 					if((btom->attr&ATOM_ATTR_2BP)&
 					   (atom[i].attr&ATOM_ATTR_2BP))
-						moldyn->pf_func2b(moldyn,
-						                  &(atom[i]),
-						                  btom,
-						                  bc);
+						moldyn->func2b(moldyn,
+						               &(atom[i]),
+						               btom,
+						               bc);
 
 					/* 3 body potential/force */
 
@@ -813,10 +841,12 @@ int potential_force_calc(t_moldyn *moldyn) {
 			if(ktom==&(atom[i]))
 				continue;
 
-			moldyn->pf_func3b(moldyn,&(atom[i]),btom,ktom,bck);
+			moldyn->func3b(moldyn,&(atom[i]),btom,ktom,bck);
 
 						} while(list_next(thisk)!=\
 						        L_NO_NEXT_ELEMENT);
+
+					}
 					
 				} while(list_next(this)!=L_NO_NEXT_ELEMENT);
 			}
@@ -833,20 +863,26 @@ int potential_force_calc(t_moldyn *moldyn) {
 int check_per_bound(t_moldyn *moldyn,t_3dvec *a) {
 	
 	double x,y,z;
+	t_3dvec *dim;
+
+	dim=&(moldyn->dim);
 
 	x=0.5*dim->x;
 	y=0.5*dim->y;
 	z=0.5*dim->z;
 
-	if(moldyn->MOLDYN_ATTR_PBX)
+	if(moldyn->status&MOLDYN_STAT_PBX) {
 		if(a->x>=x) a->x-=dim->x;
 		else if(-a->x>x) a->x+=dim->x;
-	if(moldyn->MOLDYN_ATTR_PBY)
+	}
+	if(moldyn->status&MOLDYN_STAT_PBY) {
 		if(a->y>=y) a->y-=dim->y;
 		else if(-a->y>y) a->y+=dim->y;
-	if(moldyn->MOLDYN_ATTR_PBZ)
+	}
+	if(moldyn->status&MOLDYN_STAT_PBZ) {
 		if(a->z>=z) a->z-=dim->z;
 		else if(-a->z>z) a->z+=dim->z;
+	}
 
 	return 0;
 }
@@ -858,7 +894,7 @@ int check_per_bound(t_moldyn *moldyn,t_3dvec *a) {
 
 /* harmonic oscillator potential and force */
 
-int harmonic_oscillator(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc)) {
+int harmonic_oscillator(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 
 	t_ho_params *params;
 	t_3dvec force,distance;
@@ -869,9 +905,8 @@ int harmonic_oscillator(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc)) {
 	sc=params->spring_constant;
 	equi_dist=params->equilibrium_distance;
 
-	v3_sub(&distance,&(ai->r),&(aj->r);
+	v3_sub(&distance,&(ai->r),&(aj->r));
 	
-	v3_per_bound(&distance,&(moldyn->dim));
 	if(bc) check_per_bound(moldyn,&distance);
 	d=v3_norm(&distance);
 	if(d<=moldyn->cutoff) {
@@ -890,10 +925,10 @@ 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,u;
+	double d,h1,h2;
 	double eps,sig6,sig12;
 
-	params=moldyn->pot_params;
+	params=moldyn->pot2b_params;
 	eps=params->epsilon4;
 	sig6=params->sigma6;
 	sig12=params->sigma12;
@@ -915,7 +950,7 @@ int lennard_jones(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 		d=+h1-h2;
 		d*=eps;
 		v3_scale(&force,&distance,d);
-		v3_add(&(ai->f),&(aj->f),&force);
+		v3_add(&(ai->f),&(ai->f),&force);
 	}
 
 	return 0;
@@ -960,12 +995,17 @@ 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;
+	t_3dvec dist_ij,force;
 	double d_ij;
-	double A,B,R,S,lambda;
+	double A,B,R,S,lambda,mu;
+	double f_r,df_r;
+	double f_c,df_c;
 	int num;
+	double s_r;
+	double arg;
+	double scale;
 
-	params=moldyn->pot_params;
+	params=moldyn->pot2b_params;
 	num=ai->bnum;
 	exchange=&(params->exchange);
 
@@ -992,7 +1032,8 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 		lambda=params->lambda[num];
 		/* more constants depending of atoms i and j, needed in 3bp */
 		params->exchange.B=&(params->B[num]);
-		params->exchange.mu=params->mu[num];
+		params->exchange.mu=&(params->mu[num]);
+		mu=params->mu[num];
 		params->exchange.chi=1.0;
 	}
 	else {
@@ -1003,6 +1044,7 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 		/* more constants depending of atoms i and j, needed in 3bp */
 		params->exchange.B=&(params->Bmixed);
 		params->exchange.mu=&(params->mu_m);
+		mu=params->mu_m;
 		params->exchange.chi=params->chi;
 	}
 
@@ -1014,7 +1056,7 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 	if(d_ij>S)
 		return 0;
 
-	f_r=A*exp(-lamda*d_ij);
+	f_r=A*exp(-lambda*d_ij);
 	df_r=-lambda*f_r/d_ij;
 
 	/* f_a, df_a calc + save for 3bp use */
@@ -1029,9 +1071,9 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 	}
 	else {
 		s_r=S-R;
-		arg=PI*(d_ij-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)*(PI/(s_r*d_ij));
+		df_c=-0.5*sin(arg)*(M_PI/(s_r*d_ij));
 		scale=df_c*f_r+df_r*f_c;
 		v3_scale(&force,&dist_ij,scale);
 	}
@@ -1060,15 +1102,24 @@ int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
 	t_3dvec dist_ij,dist_ik,dist_jk;
 	t_3dvec temp,force;
 	double R,S,s_r;
-	double d_ij,d_ik,d_jk;
+	double d_ij,d_ij2,d_ik,d_jk;
 	double f_c,df_c,b_ij,f_a,df_a;
-	double n,c,d,h,neta,betan,betan_1;
+	double f_c_ik,df_c_ik,arg;
+	double scale;
+	double chi;
+	double n,c,d,h,beta,betan;
+	double c2,d2,c2d2;
+	double numer,denom;
 	double theta,cos_theta,sin_theta;
+	double d_theta,d_theta1,d_theta2;
+	double h_cos,h_cos2,d2_h_cos2;
+	double frac1,bracket1,bracket2,bracket2_n_1,bracket2_n;
+	double bracket3,bracket3_pow_1,bracket3_pow;
 	int num;
 
-	params=moldyn->pot_params;
+	params=moldyn->pot3b_params;
 	num=ai->bnum;
-	exchange=params->exchange;
+	exchange=&(params->exchange);
 
 	if(!(exchange->run3bp))
 		return 0;
@@ -1098,7 +1149,7 @@ int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
 	 */
 
 	
-	v3_sub(&dist_ik,&(aj->i),&(ak->r));
+	v3_sub(&dist_ik,&(ai->r),&(ak->r));
 	if(bc) check_per_bound(moldyn,&dist_ik);
 	d_ik=v3_norm(&dist_ik);
 
@@ -1123,9 +1174,9 @@ int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
 	}
 	else {
 		s_r=S-R;
-		arg=PI*(d_ik-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)*(PI/(s_r*d_ik));
+		df_c_ik=-0.5*sin(arg)*(M_PI/(s_r*d_ik));
 	}
 	
 	v3_sub(&dist_jk,&(aj->r),&(ak->r));
@@ -1146,7 +1197,7 @@ int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
 	denom=2*d_ij*d_ik;
 	cos_theta=numer/denom;
 	sin_theta=sqrt(1.0-(cos_theta*cos_theta));
-	theta=arccos(cos_theta);
+	theta=acos(cos_theta);
 	d_theta=(-1.0/sqrt(1.0-cos_theta*cos_theta))/(denom*denom);
 	d_theta1=2*denom-numer*2*d_ik/d_ij;
 	d_theta2=2*denom-numer*2*d_ij/d_ik;
@@ -1171,12 +1222,12 @@ int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
 	b_ij=chi*bracket3_pow;
 
 	/* derivation of theta */
-	v3_scale(&force,&dist_ij,d1_theta);
+	v3_scale(&force,&dist_ij,d_theta1);
 	v3_scale(&temp,&dist_ik,d_theta2);
 	v3_add(&force,&force,&temp);
 
 	/* part 1 of derivation of b_ij */
-	v3_scale(&force,sin_theta*2*h_cos*f_c_ik*frac1);
+	v3_scale(&force,&force,sin_theta*2*h_cos*f_c_ik*frac1);
 
 	/* part 2 of derivation of b_ij */
 	v3_scale(&temp,&dist_ik,df_c_ik*bracket1);