void problem_init(int argc, char* argv[]){
// Setup constants
dt = 40; // in days
N_active = 5; // we treat pluto as a test particle. If all your particles have mass, remove this line.
tmax = 7.3e10; // 200 Myr
G = k*k; // These are the same units as used by the mercury6 code.
#ifdef OPENGL
display_wire = 1; // Show orbits.
#endif // OPENGL
init_boxwidth(200); // Init box with width 200 astronomical units
// Initial conditions
for (int i=0;i<6;i++){
struct particle p;
p.x = ss_pos[i][0]; p.y = ss_pos[i][1]; p.z = ss_pos[i][2];
p.vx = ss_vel[i][0]; p.vy = ss_vel[i][1]; p.vz = ss_vel[i][2];
p.ax = 0; p.ay = 0; p.az = 0;
p.m = ss_mass[i];
particles_add(p);
}
#ifdef INTEGRATOR_WH
// Move to heliocentric frame (required by WH integrator)
for (int i=1;i<N;i++){
particles[i].x -= particles[0].x; particles[i].y -= particles[0].y; particles[i].z -= particles[0].z;
particles[i].vx -= particles[0].vx; particles[i].vy -= particles[0].vy; particles[i].vz -= particles[0].vz;
}
particles[0].x = 0; particles[0].y = 0; particles[0].z = 0;
particles[0].vx= 0; particles[0].vy= 0; particles[0].vz= 0;
#endif // INTEGRATOR_WH
system("rm -f orbits.txt");
}
void problem_init(int argc, char* argv[]){
dt = 0.01*2.*M_PI; // initial timestep
// integrator_epsilon = 1e-2; // accuracy parameter, default is 1e-2 and should work in most cases.
#ifdef OPENGL
display_wire = 1; // show instantaneous orbits
#endif // OPENGL
init_boxwidth(10);
struct particle star;
star.m = 1;
star.x = 0; star.y = 0; star.z = 0;
star.vx = 0; star.vy = 0; star.vz = 0;
particles_add(star);
// Add planets
int N_planets = 7;
for (int i=0;i<N_planets;i++){
double a = 1.+(double)i/(double)(N_planets-1); // semi major axis
double v = sqrt(1./a); // velocity (circular orbit)
struct particle planet;
planet.m = 1e-4;
planet.x = a; planet.y = 0; planet.z = 0;
planet.vx = 0; planet.vy = v; planet.vz = 0;
particles_add(planet);
}
tools_move_to_center_of_momentum(); // This makes sure the planetary systems stays within the computational domain and doesn't drift.
}
void problem_init(int argc, char* argv[]){
dt = 0.01*2.*M_PI; // initial timestep
#ifdef OPENGL
display_wire = 1; // show instantaneous orbits
#endif // OPENGL
collision_resolve = collision_resolve_merger; // Setup our own collision routine.
init_boxwidth(10);
struct particle star;
star.m = 1;
star.r = 0.1;
star.x = 0; star.y = 0; star.z = 0;
star.vx = 0; star.vy = 0; star.vz = 0;
particles_add(star);
// Add planets
int N_planets = 7;
for (int i=0;i<N_planets;i++){
double a = 1.+(double)i/(double)(N_planets-1); // semi major axis in AU
double v = sqrt(1./a); // velocity (circular orbit)
struct particle planet;
planet.m = 1e-4;
planet.r = 4e-2; // radius in AU (it is unphysically large in this example)
planet.lastcollision = 0; // The first time particles can collide with each other
planet.x = a; planet.y = 0; planet.z = 0;
planet.vx = 0; planet.vy = v; planet.vz = 0;
particles_add(planet);
}
tools_move_to_center_of_momentum(); // This makes sure the planetary systems stays within the computational domain and doesn't drift.
}
void problem_init(int argc, char* argv[]){
dt = 0.012*2.*M_PI; // initial timestep
integrator = HYBRID;
//softening = 0.001;
//integrator = IAS15;
//integrator = WHFAST;
integrator_whfast_corrector = 5;
integrator_whfast_synchronize_manually = 1;
#ifdef OPENGL
display_wire = 1; // show instantaneous orbits
#endif // OPENGL
init_boxwidth(20);
struct particle star;
star.m = 1;
star.x = 0; star.y = 0; star.z = 0;
star.vx = 0; star.vy = 0; star.vz = 0;
particles_add(star);
// Add planets
int N_planets = 3;
for (int i=0;i<N_planets;i++){
double a = 1.+.1*(double)i; // semi major axis
double v = sqrt(1./a); // velocity (circular orbit)
struct particle planet;
planet.m = 2e-5;
planet.x = a; planet.y = 0; planet.z = 0;
planet.vx = 0; planet.vy = v; planet.vz = 0;
particles_add(planet);
}
tools_move_to_center_of_momentum(); // This makes sure the planetary systems stays within the computational domain and doesn't drift.
e_init = tools_energy();
system("rm -rf energy.txt");
}
void problem_init(int argc, char* argv[]) {
// Setup constants
integrator = WHFAST;
dt = 0.001*2.*M_PI; // initial timestep (in days)
init_boxwidth(200);
// Initial conditions
{
struct particle p = {.m=1.,.x=0,.y=0.,.z=0.,.vx=0,.vy=0.,.vz=0.};
particles_add(p);
}
{
double e = 0.999;
struct particle p = {.m=0.,.x=0.01,.y=0.,.z=0.,.vx=0,.vy=0.*sqrt((1.+e)/(1.-e)),.vz=0.};
particles_add(p);
}
tools_move_to_center_of_momentum();
//problem_additional_forces = additional_forces;
// Add megno particles
//tools_megno_init(1e-16); // N = 6 after this function call.
system("rm -f *.txt");
ei = energy();
}
void additional_forces() {
particles[1].ax += 0.12/6.;
}
double energy() {
double e_kin = 0.;
double e_pot = 0.;
struct particle pi = particles[1];
e_kin += 0.5 * (pi.vx*pi.vx + pi.vy*pi.vy + pi.vz*pi.vz);
struct particle pj = particles[0];
double dx = pi.x - pj.x;
double dy = pi.y - pj.y;
double dz = pi.z - pj.z;
e_pot -= G*pj.m/sqrt(dx*dx + dy*dy + dz*dz);
return e_kin +e_pot;
}
int no =0;
void problem_output() {
no++;
// printf("%d\n", no);
if (output_check(1000.*dt)) {
output_timing();
}
// FILE* f = fopen("Y.txt","a+");
// fprintf(f,"%e %e %e\n",t,(energy()-ei)/ei,tools_megno());
// fclose(f);
}
void problem_init(int argc, char* argv[]){
dt = 0;
display_pause_sim = 1;
boxsize = 100;
FILE* f;
if (argc<=1){
f = stdin;
printf("\n\nReading from stdin.\n");
}else{
f = fopen(argv[1],"r");
printf("\n\nReading from file.\n");
}
if (f==NULL){
printf("\n\nERROR. Cannot open file.\n");
exit(-1);
}
// Read in data.
double x, y, z, r;
if (fscanf(f,"%lf %lf %lf %lf", &x, &y, &z, &r)==EOF){
printf("\n\nERROR. Empty file.\n");
exit(-1);
}
double max_x = x, min_x = x;
double max_y = y, min_y = y;
double max_z = z, min_z = z;
init_boxwidth(1);
while(fscanf(f, "%lf %lf %lf %lf", &x, &y, &z, &r)!=EOF){
struct particle p = {.x=x, .y=y, .z=z, .r=r};
particles_add_local(p);
if (x>max_x) max_x = x;
if (y>max_y) max_y = y;
if (z>max_z) max_z = z;
if (x<min_x) min_x = x;
if (y<min_y) min_y = y;
if (z<min_z) min_z = z;
}
printf("\nFound %d particles in file.\n",N);
fclose(f);
// Resize box.
boxsize = max_x - min_x;
if (max_y - min_y > boxsize) boxsize = max_y - min_y;
if (max_z - min_z > boxsize) boxsize = max_z - min_z;
boxsize*=1.01;
boxsize_max = boxsize_x = boxsize_y = boxsize_z = boxsize;
// Move particles to center.
for (int i=0;i<N;i++){
particles[i].x -= (max_x+min_x)/2.;
particles[i].y -= (max_y+min_y)/2.;
particles[i].z -= (max_z+min_z)/2.;
}
}
void problem_init(int argc, char* argv[]){
// Setup constants
dt = 10; // initial timestep (in days)
//integrator = IAS15;
integrator = WHFAST;
const double k = 0.01720209895; // Gaussian constant
G = k*k; // These are the same units that mercury6 uses
init_boxwidth(200);
// Initial conditions
for (int i=0;i<3;i++){
struct particle p;
p.x = ss_pos[i][0]; p.y = ss_pos[i][1]; p.z = ss_pos[i][2];
p.vx = ss_vel[i][0]; p.vy = ss_vel[i][1]; p.vz = ss_vel[i][2];
p.ax = 0; p.ay = 0; p.az = 0;
p.m = ss_mass[i];
particles_add(p);
}
tools_move_to_center_of_momentum();
// Add megno particles
tools_megno_init(1e-16); // N = 6 after this function call.
// The first half of particles are real particles, the second half are particles following the variational equations.
}
void problem_init(int argc, char* argv[]){
// Setup constants
dt = 4; // in days
tmax = 7.3e10; // 200 Myr
G = 1.4880826e-34; // in AU^3 / kg / day^2.
init_boxwidth(200); // Init box with width 200 astronomical units
integrator_whfast_synchronize_manually = 1; // Need to call integrator_synchronize() before outputs.
integrator_force_is_velocitydependent = 0; // Force only depends on positions.
//integrator = WH;
integrator = WHFAST;
//integrator = IAS15;
// Initial conditions
for (int i=0;i<10;i++){
struct particle p;
p.x = ss_pos[i][0]; p.y = ss_pos[i][1]; p.z = ss_pos[i][2];
p.vx = ss_vel[i][0]; p.vy = ss_vel[i][1]; p.vz = ss_vel[i][2];
p.ax = 0; p.ay = 0; p.az = 0;
p.m = ss_mass[i];
particles_add(p);
}
if (integrator==WH){
// Move to heliocentric frame (required by WH integrator)
for (int i=1;i<N;i++){
particles[i].x -= particles[0].x; particles[i].y -= particles[0].y; particles[i].z -= particles[0].z;
particles[i].vx -= particles[0].vx; particles[i].vy -= particles[0].vy; particles[i].vz -= particles[0].vz;
}
particles[0].x = 0; particles[0].y = 0; particles[0].z = 0;
particles[0].vx= 0; particles[0].vy= 0; particles[0].vz= 0;
}else{
tools_move_to_center_of_momentum();
}
//tools_megno_init(1e-16);
e_init = energy();
system("rm -f energy.txt");
system("rm -f pos.txt");
}
