void evolve_system(uint32_t timesteps)
{
/* ******************************************* *
* MAIN LOOP
*/
count_forces(); // function leap_frog() requries
for (uint16_t ii=0; ii < timesteps; ii++)
{
leap_frog();
}
}
int main ()
{
/* Se crean las variables del hamiltoniano para resolver con Runge Kutta*/
double q1_RK, q3_RK, p1_RK, p3_RK;
/* Se crean las variables del hamiltoniano para resolver con el Integrador Simplectico*/
double q1_LF, q3_LF, p1_LF, p3_LF;
/* Distancia vertical entre los cuerpos masivos*/
double eps=1.0;
/* Tiempo total*/
double T=2800;
/* Paso de tiempo */
double h=0.006;
/* Numero de pasos*/
int n=(int)(T/h);
// Elementos aleatorios
long seed;
seed=n;
srand48( seed );
/* Condiciones iniciales*/
q1_RK=q1_LF=0.35355;
q3_RK=q3_LF=2*drand48()-1;
p1_RK=p1_LF=0.0;
p3_RK=p3_LF=2*drand48()-1;
double t=0.0;
int i;
//Hamiltonianos
double H1,H2;
for (i=0;i<n;i++)
{
H1=0.5*pow(p1_RK,2) - 0.5*pow( (4*pow(q1_RK,2)+pow(eps,2)) ,-0.5);
H2=0.5*pow(p1_LF,2) - 0.5*pow( (4*pow(q1_LF,2)+pow(eps,2)) ,-0.5);
printf("%.6f %.6f %.4f\n",H1,H2,t);
RK4(h,&q1_RK,&p1_RK,&q3_RK,&p3_RK,eps);
leap_frog(h,&q1_LF,&p1_LF,&q3_LF,&p3_LF,eps);
t+=h;
}
return 0;
}
/*
* Perform simulation for arbitrary time of 3ps to termalize
*/
void termalize_system()
{
const uint16_t time = 3; // time in ps
const uint16_t timesteps = time*( (uint16_t) round(1./global.dt) );
printf("# TERMALIZATION\n");
printf("Performing termalization for %d timesteps with dt=%e [%.1lf ps]\n",timesteps,global.dt,(double) time);
count_forces(); // function leap_frog() requries
for (uint16_t ii=0; ii < timesteps; ii++)
{
leap_frog();
}
printf("Termalization done\n");
printf("\n");
}
void perform_experiment(double time, uint16_t steps_per_stats, uint16_t steps_per_positions)
{
uint16_t timesteps = ( (uint16_t) round(time/global.dt) );
// double* pressure_arr = malloc( timesteps * sizeof(double) );
// double* sig_pressure_arr = malloc( timesteps * sizeof(double) );
// double* temp_arr = malloc( timesteps * sizeof(double) );
// double* sig_temp_arr = malloc( timesteps * sizeof(double) );
// ====================== FILES ==============================================
/*
//get current date
char datetime[20];
time_t t;
time(&t);
strftime(datetime, sizeof(datetime), "%F_%T", localtime(&t));
*/
char dirname[256];
sprintf( dirname,"Dane_dt=%e",global.dt);
struct stat st = {0};
if (stat(dirname, &st) == -1) { mkdir(dirname, 0777); }
char filename_pT[256];
sprintf( filename_pT,"pT_stats.txt");
FILE* file_pT = fopen(filename_pT,"a");
char filename_stats[256];
sprintf( filename_stats,"%s/stats_T0=%.1lf.txt",dirname,global.T0);
FILE* file_stats = fopen(filename_stats,"w");
char filename_positions[256];
sprintf( filename_positions,"%s/positions_T0=%.1lf.bin",dirname,global.T0);
FILE* file_pos = fopen(filename_positions,"wb");
char filename_momenta[256];
sprintf( filename_momenta,"%s/momenta_T0=%.1lf.bin",dirname,global.T0);
FILE* file_mom = fopen(filename_momenta,"wb");
// ============================= MAIN LOOP =========================================
double av_pressure = 0.;
double u_pressure = 0.;
double av_temp = 0.;
double u_temp = 0.;
printf("# Making simulation for %.1lf ps [%d timesteps]\n",time,timesteps);
count_forces(); // function leap_frog() requries
for (uint16_t ii=0; ii < timesteps; ii++)
{
// make algorithm step
leap_frog();
const double p = pressure();
const double T = temperature();
av_pressure += p/timesteps;
u_pressure += p*p/timesteps;
av_temp += T/timesteps;
u_temp += T*T/timesteps;
if (!(ii%steps_per_stats))
{
fprintf(file_stats,"%e\t%e\t%e\t%e\n",av_temp,u_temp,av_pressure,u_pressure);
}
else if (!(ii%steps_per_positions))
{
fwrite(global.x_arr,sizeof(double), global.N, file_pos);
fwrite(global.y_arr,sizeof(double), global.N, file_pos);
fwrite(global.z_arr,sizeof(double), global.N, file_pos);
fwrite(global.px_arr,sizeof(double), global.N, file_mom);
fwrite(global.py_arr,sizeof(double), global.N, file_mom);
fwrite(global.pz_arr,sizeof(double), global.N, file_mom);
}
}
// ========================= MEANS ========================================
//av_temp /= timesteps;
u_temp = sqrt( u_temp - av_temp*av_temp );
//av_pressure /= timesteps;
u_pressure = sqrt( u_pressure - av_pressure*av_pressure );
//fprintf(file_pT,"\n","T","u(T)","p","u(p)");
fprintf(file_pT,"%e\t%e\t%e\t%e\n",av_temp,u_temp,av_pressure,u_pressure);
fclose(file_stats);
fclose(file_pT);
fclose(file_pos);
fclose(file_mom);
// free(pressure_arr);
// free(sig_pressure_arr);
// free(temp_arr);
// free(sig_arr);
}
