+#include "moldyn.h"
+#include "report/report.h"
+
+int moldyn_init(t_moldyn *moldyn,int argc,char **argv) {
+
+ printf("[moldyn] init\n");
+
+ memset(moldyn,0,sizeof(t_moldyn));
+
+ moldyn->argc=argc;
+ moldyn->args=argv;
+
+ rand_init(&(moldyn->random),NULL,1);
+ moldyn->random.status|=RAND_STAT_VERBOSE;
+
+ return 0;
+}
+
+int moldyn_shutdown(t_moldyn *moldyn) {
+
+ printf("[moldyn] shutdown\n");
+
+ moldyn_log_shutdown(moldyn);
+ link_cell_shutdown(moldyn);
+ rand_close(&(moldyn->random));
+ free(moldyn->atom);
+
+ return 0;
+}
+
+int set_int_alg(t_moldyn *moldyn,u8 algo) {
+
+ printf("[moldyn] integration algorithm: ");
+
+ switch(algo) {
+ case MOLDYN_INTEGRATE_VERLET:
+ moldyn->integrate=velocity_verlet;
+ printf("velocity verlet\n");
+ break;
+ default:
+ printf("unknown integration algorithm: %02x\n",algo);
+ printf("unknown\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+int set_cutoff(t_moldyn *moldyn,double cutoff) {
+
+ moldyn->cutoff=cutoff;
+
+ printf("[moldyn] cutoff [A]: %f\n",moldyn->cutoff);
+
+ return 0;
+}
+
+int set_temperature(t_moldyn *moldyn,double t_ref) {
+
+ moldyn->t_ref=t_ref;
+
+ printf("[moldyn] temperature [K]: %f\n",moldyn->t_ref);
+
+ return 0;
+}
+
+int set_pressure(t_moldyn *moldyn,double p_ref) {
+
+ moldyn->p_ref=p_ref;
+
+ printf("[moldyn] pressure [bar]: %f\n",moldyn->p_ref/BAR);
+
+ return 0;
+}
+
+int set_pt_scale(t_moldyn *moldyn,u8 ptype,double ptc,u8 ttype,double ttc) {
+
+ moldyn->pt_scale=(ptype|ttype);
+ moldyn->t_tc=ttc;
+ moldyn->p_tc=ptc;
+
+ printf("[moldyn] p/t scaling:\n");
+
+ printf(" p: %s",ptype?"yes":"no ");
+ if(ptype)
+ printf(" | type: %02x | factor: %f",ptype,ptc);
+ printf("\n");
+
+ printf(" t: %s",ttype?"yes":"no ");
+ if(ttype)
+ printf(" | type: %02x | factor: %f",ttype,ttc);
+ printf("\n");
+
+ return 0;
+}
+
+int set_dim(t_moldyn *moldyn,double x,double y,double z,u8 visualize) {
+
+ moldyn->dim.x=x;
+ moldyn->dim.y=y;
+ moldyn->dim.z=z;
+
+ moldyn->volume=x*y*z;
+
+ if(visualize) {
+ moldyn->vis.dim.x=x;
+ moldyn->vis.dim.y=y;
+ moldyn->vis.dim.z=z;
+ }
+
+ moldyn->dv=0.000001*moldyn->volume;
+
+ printf("[moldyn] dimensions in A and A^3 respectively:\n");
+ printf(" x: %f\n",moldyn->dim.x);
+ printf(" y: %f\n",moldyn->dim.y);
+ printf(" z: %f\n",moldyn->dim.z);
+ printf(" volume: %f\n",moldyn->volume);
+ printf(" visualize simulation box: %s\n",visualize?"yes":"no");
+ printf(" delta volume (pressure calc): %f\n",moldyn->dv);
+
+ return 0;
+}
+
+int set_nn_dist(t_moldyn *moldyn,double dist) {
+
+ moldyn->nnd=dist;
+
+ return 0;
+}
+
+int set_pbc(t_moldyn *moldyn,u8 x,u8 y,u8 z) {
+
+ printf("[moldyn] periodic boundary conditions:\n");
+
+ if(x)
+ moldyn->status|=MOLDYN_STAT_PBX;
+
+ if(y)
+ moldyn->status|=MOLDYN_STAT_PBY;
+
+ if(z)
+ moldyn->status|=MOLDYN_STAT_PBZ;
+
+ printf(" x: %s\n",x?"yes":"no");
+ printf(" y: %s\n",y?"yes":"no");
+ printf(" z: %s\n",z?"yes":"no");
+
+ return 0;
+}
+
+int set_potential1b(t_moldyn *moldyn,pf_func1b func) {
+
+ moldyn->func1b=func;
+
+ return 0;
+}
+
+int set_potential2b(t_moldyn *moldyn,pf_func2b func) {
+
+ moldyn->func2b=func;
+
+ return 0;
+}
+
+int set_potential3b_j1(t_moldyn *moldyn,pf_func2b func) {
+
+ moldyn->func3b_j1=func;
+
+ return 0;
+}
+
+int set_potential3b_j2(t_moldyn *moldyn,pf_func2b func) {
+
+ 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;
+}
+
+int set_avg_skip(t_moldyn *moldyn,int skip) {
+
+ printf("[moldyn] skip %d steps before starting average calc\n",skip);
+ moldyn->avg_skip=skip;
+
+ return 0;
+}
+
+int moldyn_set_log_dir(t_moldyn *moldyn,char *dir) {
+
+ strncpy(moldyn->vlsdir,dir,127);
+
+ 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) {
+
+ char filename[128];
+ int ret;
+
+ printf("[moldyn] set log: ");
+
+ switch(type) {
+ case LOG_TOTAL_ENERGY:
+ moldyn->ewrite=timer;
+ snprintf(filename,127,"%s/energy",moldyn->vlsdir);
+ moldyn->efd=open(filename,
+ O_WRONLY|O_CREAT|O_EXCL,
+ S_IRUSR|S_IWUSR);
+ if(moldyn->efd<0) {
+ perror("[moldyn] energy log fd open");
+ return moldyn->efd;
+ }
+ dprintf(moldyn->efd,"# total energy log file\n");
+ printf("total energy (%d)\n",timer);
+ break;
+ case LOG_TOTAL_MOMENTUM:
+ moldyn->mwrite=timer;
+ snprintf(filename,127,"%s/momentum",moldyn->vlsdir);
+ moldyn->mfd=open(filename,
+ O_WRONLY|O_CREAT|O_EXCL,
+ S_IRUSR|S_IWUSR);
+ if(moldyn->mfd<0) {
+ perror("[moldyn] momentum log fd open");
+ return moldyn->mfd;
+ }
+ 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);
+ break;
+ case VISUAL_STEP:
+ moldyn->vwrite=timer;
+ ret=visual_init(&(moldyn->vis),moldyn->vlsdir);
+ if(ret<0) {
+ printf("[moldyn] visual init failure\n");
+ return ret;
+ }
+ 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;
+ }
+
+ return 0;
+}
+
+int moldyn_log_shutdown(t_moldyn *moldyn) {
+
+ char sc[256];
+
+ printf("[moldyn] log shutdown\n");
+ 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;
+}
+
+/*
+ * creating lattice functions
+ */
+
+int create_lattice(t_moldyn *moldyn,u8 type,double lc,int element,double mass,
+ u8 attr,u8 brand,int a,int b,int c,t_3dvec *origin) {
+
+ int new,count;
+ int ret;
+ t_3dvec orig;
+ void *ptr;
+ t_atom *atom;
+
+ new=a*b*c;
+ count=moldyn->count;
+
+ /* how many atoms do we expect */
+ if(type==CUBIC) new*=1;
+ if(type==FCC) new*=4;
+ if(type==DIAMOND) new*=8;
+
+ /* allocate space for atoms */
+ ptr=realloc(moldyn->atom,(count+new)*sizeof(t_atom));
+ if(!ptr) {
+ perror("[moldyn] realloc (create lattice)");
+ return -1;
+ }
+ moldyn->atom=ptr;
+ atom=&(moldyn->atom[count]);
+
+ /* 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:
+ set_nn_dist(moldyn,lc);
+ ret=cubic_init(a,b,c,lc,atom,&orig);
+ break;
+ case FCC:
+ 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:
+ 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);
+ return -1;
+ }
+
+ /* debug */
+ if(ret!=new) {
+ printf("[moldyn] creating lattice failed\n");
+ printf(" amount of atoms\n");
+ printf(" - expected: %d\n",new);
+ printf(" - created: %d\n",ret);
+ return -1;
+ }
+
+ moldyn->count+=new;
+ printf("[moldyn] created lattice with %d atoms\n",new);
+
+ for(ret=0;ret<new;ret++) {
+ atom[ret].element=element;
+ atom[ret].mass=mass;
+ atom[ret].attr=attr;
+ atom[ret].brand=brand;
+ atom[ret].tag=count+ret;
+ check_per_bound(moldyn,&(atom[ret].r));
+ atom[ret].r_0=atom[ret].r;
+ }
+
+ /* update total system mass */
+ total_mass_calc(moldyn);
+
+ return ret;
+}
+
+int add_atom(t_moldyn *moldyn,int element,double mass,u8 brand,u8 attr,
+ t_3dvec *r,t_3dvec *v) {
+
+ t_atom *atom;
+ void *ptr;
+ int count;
+
+ atom=moldyn->atom;
+ count=(moldyn->count)++;
+
+ ptr=realloc(atom,(count+1)*sizeof(t_atom));
+ if(!ptr) {
+ perror("[moldyn] realloc (add atom)");
+ return -1;
+ }
+ moldyn->atom=ptr;
+
+ atom=moldyn->atom;
+ atom[count].r=*r;
+ atom[count].v=*v;
+ atom[count].element=element;
+ atom[count].mass=mass;
+ atom[count].brand=brand;
+ atom[count].tag=count;
+ atom[count].attr=attr;
+ check_per_bound(moldyn,&(atom[count].r));
+ atom[count].r_0=atom[count].r;
+
+ /* update total system mass */
+ total_mass_calc(moldyn);
+
+ return 0;
+}
+
+/* cubic init */
+int cubic_init(int a,int b,int c,double lc,t_atom *atom,t_3dvec *origin) {
+
+ int count;
+ t_3dvec r;
+ int i,j,k;
+ t_3dvec o;
+
+ count=0;
+ if(origin)
+ v3_copy(&o,origin);
+ else
+ v3_zero(&o);
+
+ 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,k,l;
+ t_3dvec o,r,n;
+ t_3dvec basis[3];
+
+ count=0;
+ if(origin)
+ v3_copy(&o,origin);
+ else
+ v3_zero(&o);
+
+ /* construct the basis */
+ 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;
+
+ /* fill up the room */
+ 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++) {
+ /* first atom */
+ v3_copy(&(atom[count].r),&r);
+ 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.y+=lc;
+ }
+ r.x+=lc;
+ }
+
+ /* coordinate transformation */
+ 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;
+}
+
+int diamond_init(int a,int b,int c,double lc,t_atom *atom,t_3dvec *origin) {
+
+ int count;
+ t_3dvec o;
+
+ count=fcc_init(a,b,c,lc,atom,origin);
+
+ o.x=0.25*lc;
+ o.y=0.25*lc;
+ o.z=0.25*lc;
+
+ if(origin) v3_add(&o,&o,origin);
+
+ count+=fcc_init(a,b,c,lc,&atom[count],&o);
+
+ return count;
+}
+
+int destroy_atoms(t_moldyn *moldyn) {
+
+ if(moldyn->atom) free(moldyn->atom);
+
+ return 0;
+}
+
+int thermal_init(t_moldyn *moldyn,u8 equi_init) {
+
+ /*
+ * - gaussian distribution of velocities
+ * - zero total momentum
+ * - velocity scaling (E = 3/2 N k T), E: kinetic energy
+ */
+
+ int i;
+ double v,sigma;
+ t_3dvec p_total,delta;
+ t_atom *atom;
+ t_random *random;
+
+ atom=moldyn->atom;
+ random=&(moldyn->random);
+
+ printf("[moldyn] thermal init (equi init: %s)\n",equi_init?"yes":"no");
+
+ /* gaussian distribution of velocities */
+ v3_zero(&p_total);
+ for(i=0;i<moldyn->count;i++) {
+ sigma=sqrt(2.0*K_BOLTZMANN*moldyn->t_ref/atom[i].mass);
+ /* x direction */
+ v=sigma*rand_get_gauss(random);
+ atom[i].v.x=v;
+ p_total.x+=atom[i].mass*v;
+ /* y direction */
+ v=sigma*rand_get_gauss(random);
+ atom[i].v.y=v;
+ p_total.y+=atom[i].mass*v;
+ /* z direction */
+ v=sigma*rand_get_gauss(random);
+ atom[i].v.z=v;
+ p_total.z+=atom[i].mass*v;
+ }
+
+ /* zero total momentum */
+ v3_scale(&p_total,&p_total,1.0/moldyn->count);
+ for(i=0;i<moldyn->count;i++) {
+ v3_scale(&delta,&p_total,1.0/atom[i].mass);
+ v3_sub(&(atom[i].v),&(atom[i].v),&delta);
+ }
+
+ /* velocity scaling */
+ scale_velocity(moldyn,equi_init);
+
+ return 0;
+}
+
+double total_mass_calc(t_moldyn *moldyn) {
+
+ int i;
+
+ moldyn->mass=0.0;
+
+ for(i=0;i<moldyn->count;i++)
+ moldyn->mass+=moldyn->atom[i].mass;
+
+ return moldyn->mass;
+}
+
+double temperature_calc(t_moldyn *moldyn) {
+
+ /* assume up to date kinetic energy, which is 3/2 N k_B T */
+
+ moldyn->t=(2.0*moldyn->ekin)/(3.0*K_BOLTZMANN*moldyn->count);
+
+ return moldyn->t;
+}
+
+double get_temperature(t_moldyn *moldyn) {
+
+ return moldyn->t;
+}
+
+int scale_velocity(t_moldyn *moldyn,u8 equi_init) {
+
+ int i;
+ double e,scale;
+ t_atom *atom;
+ int count;
+
+ atom=moldyn->atom;
+
+ /*
+ * - velocity scaling (E = 3/2 N k T), E: kinetic energy
+ */
+
+ /* get kinetic energy / temperature & count involved atoms */
+ e=0.0;
+ count=0;
+ for(i=0;i<moldyn->count;i++) {
+ if((equi_init&TRUE)||(atom[i].attr&ATOM_ATTR_HB)) {
+ e+=atom[i].mass*v3_absolute_square(&(atom[i].v));
+ count+=1;
+ }
+ }
+ e*=0.5;
+ if(count!=0) moldyn->t=e/(1.5*count*K_BOLTZMANN);
+ else return 0; /* no atoms involved in scaling! */
+
+ /* (temporary) hack for e,t = 0 */
+ if(e==0.0) {
+ moldyn->t=0.0;
+ if(moldyn->t_ref!=0.0) {
+ thermal_init(moldyn,equi_init);
+ return 0;
+ }
+ else
+ return 0; /* no scaling needed */
+ }
+
+
+ /* get scaling factor */
+ scale=moldyn->t_ref/moldyn->t;
+ if(equi_init&TRUE)
+ scale*=2.0;
+ else
+ if(moldyn->pt_scale&T_SCALE_BERENDSEN)
+ scale=1.0+(scale-1.0)/moldyn->t_tc;
+ scale=sqrt(scale);
+
+ /* velocity scaling */
+ for(i=0;i<moldyn->count;i++) {
+ if((equi_init&TRUE)||(atom[i].attr&ATOM_ATTR_HB))
+ v3_scale(&(atom[i].v),&(atom[i].v),scale);
+ }
+
+ return 0;
+}
+
+double ideal_gas_law_pressure(t_moldyn *moldyn) {
+
+ double p;
+
+ p=moldyn->count*moldyn->t*K_BOLTZMANN/moldyn->volume;
+
+ return p;
+}
+
+double virial_sum(t_moldyn *moldyn) {
+
+ int i;
+ double v;
+ t_virial *virial;
+
+ /* virial (sum over atom virials) */
+ v=0.0;
+ for(i=0;i<moldyn->count;i++) {
+ virial=&(moldyn->atom[i].virial);
+ v+=(virial->xx+virial->yy+virial->zz);
+ }
+ moldyn->virial=v;
+
+ /* global virial (absolute coordinates) */
+ virial=&(moldyn->gvir);
+ moldyn->gv=virial->xx+virial->yy+virial->zz;
+
+ return moldyn->virial;
+}
+
+double pressure_calc(t_moldyn *moldyn) {
+
+ /*
+ * PV = NkT + <W>
+ * with W = 1/3 sum_i f_i r_i (- skipped!)
+ * virial = sum_i f_i r_i
+ *
+ * => P = (2 Ekin + virial) / (3V)
+ */
+
+ /* assume up to date virial & up to date kinetic energy */
+
+ /* pressure (atom virials) */
+ moldyn->p=2.0*moldyn->ekin+moldyn->virial;
+ moldyn->p/=(3.0*moldyn->volume);
+
+ /* pressure (absolute coordinates) */
+ moldyn->gp=2.0*moldyn->ekin+moldyn->gv;
+ moldyn->gp/=(3.0*moldyn->volume);
+
+ return moldyn->p;
+}
+
+int average_and_fluctuation_calc(t_moldyn *moldyn) {
+
+ if(moldyn->total_steps<moldyn->avg_skip)
+ return 0;
+
+ int denom=moldyn->total_steps+1-moldyn->avg_skip;
+
+ /* assume up to date energies, temperature, pressure etc */
+
+ /* kinetic energy */
+ moldyn->k_sum+=moldyn->ekin;
+ moldyn->k2_sum+=(moldyn->ekin*moldyn->ekin);
+ moldyn->k_avg=moldyn->k_sum/denom;
+ moldyn->k2_avg=moldyn->k2_sum/denom;
+ moldyn->dk2_avg=moldyn->k2_avg-(moldyn->k_avg*moldyn->k_avg);
+
+ /* potential energy */
+ moldyn->v_sum+=moldyn->energy;
+ moldyn->v2_sum+=(moldyn->energy*moldyn->energy);
+ moldyn->v_avg=moldyn->v_sum/denom;
+ moldyn->v2_avg=moldyn->v2_sum/denom;
+ moldyn->dv2_avg=moldyn->v2_avg-(moldyn->v_avg*moldyn->v_avg);
+
+ /* temperature */
+ moldyn->t_sum+=moldyn->t;
+ moldyn->t_avg=moldyn->t_sum/denom;
+
+ /* virial */
+ moldyn->virial_sum+=moldyn->virial;
+ moldyn->virial_avg=moldyn->virial_sum/denom;
+ moldyn->gv_sum+=moldyn->gv;
+ moldyn->gv_avg=moldyn->gv_sum/denom;
+
+ /* pressure */
+ moldyn->p_sum+=moldyn->p;
+ moldyn->p_avg=moldyn->p_sum/denom;
+ moldyn->gp_sum+=moldyn->gp;
+ moldyn->gp_avg=moldyn->gp_sum/denom;
+
+ return 0;
+}
+
+int get_heat_capacity(t_moldyn *moldyn) {
+
+ double temp2,ighc;
+
+ /* averages needed for heat capacity calc */
+ if(moldyn->total_steps<moldyn->avg_skip)
+ return 0;
+
+ /* (temperature average)^2 */
+ temp2=moldyn->t_avg*moldyn->t_avg;
+ printf("[moldyn] specific heat capacity for T=%f K [J/(kg K)]\n",
+ moldyn->t_avg);
+
+ /* ideal gas contribution */
+ ighc=3.0*moldyn->count*K_BOLTZMANN/2.0;
+ printf(" ideal gas contribution: %f\n",
+ ighc/moldyn->mass*KILOGRAM/JOULE);
+
+ /* specific heat for nvt ensemble */
+ moldyn->c_v_nvt=moldyn->dv2_avg/(K_BOLTZMANN*temp2)+ighc;
+ moldyn->c_v_nvt/=moldyn->mass;
+
+ /* specific heat for nve ensemble */
+ moldyn->c_v_nve=ighc/(1.0-(moldyn->dv2_avg/(ighc*K_BOLTZMANN*temp2)));
+ moldyn->c_v_nve/=moldyn->mass;
+
+ printf(" NVE: %f\n",moldyn->c_v_nve*KILOGRAM/JOULE);
+ printf(" NVT: %f\n",moldyn->c_v_nvt*KILOGRAM/JOULE);
+printf(" --> <dV2> sim: %f experimental: %f\n",moldyn->dv2_avg,1.5*moldyn->count*K_B2*moldyn->t_avg*moldyn->t_avg*(1.0-1.5*moldyn->count*K_BOLTZMANN/(700*moldyn->mass*JOULE/KILOGRAM)));
+
+ return 0;
+}
+
+double thermodynamic_pressure_calc(t_moldyn *moldyn) {
+
+ t_3dvec dim,*tp;
+ double u_up,u_down,dv;
+ double scale,p;
+ t_atom *store;
+
+ /*
+ * 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");
+ return -1;
+ }
+
+ /* save unscaled potential energy + atom/dim configuration */
+ memcpy(store,moldyn->atom,moldyn->count*sizeof(t_atom));
+ dim=moldyn->dim;
+
+ /* 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);
+ u_up=moldyn->energy;
+
+ /* restore atomic configuration + dim */
+ memcpy(moldyn->atom,store,moldyn->count*sizeof(t_atom));
+ moldyn->dim=dim;
+
+ /* 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);
+ 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;
+
+ /* restore energy */
+ potential_force_calc(moldyn);
+
+ link_cell_shutdown(moldyn);
+ link_cell_init(moldyn,QUIET);
+
+ return p;
+}
+
+double get_pressure(t_moldyn *moldyn) {
+
+ return moldyn->p;
+
+}
+
+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;
+
+ return 0;
+}
+
+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;
+ if(y) r->y*=scale;
+ if(z) r->z*=scale;
+ }
+
+ return 0;
+}
+
+int scale_volume(t_moldyn *moldyn) {
+
+ t_3dvec *dim,*vdim;
+ double scale;
+ t_linkcell *lc;
+
+ vdim=&(moldyn->vis.dim);
+ dim=&(moldyn->dim);
+ lc=&(moldyn->lc);
+
+ /* 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;
+
+ /* 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;
+ }
+
+ /* 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,QUIET);
+ } else {
+ lc->x*=scale;
+ lc->y*=scale;
+ lc->z*=scale;
+ }
+
+ return 0;
+
+}