void tools_megno_init(double delta){
int _N_megno = N;
tools_megno_Ys = 0.;
tools_megno_Yss = 0.;
tools_megno_cov_Yt = 0.;
tools_megno_var_t = 0.;
tools_megno_n = 0;
tools_megno_mean_Y = 0;
tools_megno_mean_t = 0;
tools_megno_delta0 = delta;
for (int i=0;i<_N_megno;i++){
struct particle megno = {
.m = particles[i].m,
.x = tools_normal(1.),
.y = tools_normal(1.),
.z = tools_normal(1.),
.vx = tools_normal(1.),
.vy = tools_normal(1.),
.vz = tools_normal(1.) };
double deltad = delta/sqrt(megno.x*megno.x + megno.y*megno.y + megno.z*megno.z + megno.vx*megno.vx + megno.vy*megno.vy + megno.vz*megno.vz); // rescale
megno.x *= deltad;
megno.y *= deltad;
megno.z *= deltad;
megno.vx *= deltad;
megno.vy *= deltad;
megno.vz *= deltad;
particles_add(megno);
}
N_megno = _N_megno;
}
double tools_megno(void){ // Returns the MEGNO <Y>
if (t==0.) return 0.;
return tools_megno_Yss/t;
}
double tools_lyapunov(void){ // Returns the largest Lyapunov characteristic number (LCN), or maximal Lyapunov exponent
if (t==0.) return 0.;
return tools_megno_cov_Yt/tools_megno_var_t;
}
double tools_megno_deltad_delta(void){
double deltad = 0;
double delta2 = 0;
for (int i=N-N_megno;i<N;i++){
deltad += particles[i].vx * particles[i].x;
deltad += particles[i].vy * particles[i].y;
deltad += particles[i].vz * particles[i].z;
deltad += particles[i].ax * particles[i].vx;
deltad += particles[i].ay * particles[i].vy;
deltad += particles[i].az * particles[i].vz;
delta2 += particles[i].x * particles[i].x;
delta2 += particles[i].y * particles[i].y;
delta2 += particles[i].z * particles[i].z;
delta2 += particles[i].vx * particles[i].vx;
delta2 += particles[i].vy * particles[i].vy;
delta2 += particles[i].vz * particles[i].vz;
}
return deltad/delta2;
}
void problem_init(int argc, char* argv[]){
// Setup constants
#ifdef GRAVITY_TREE
opening_angle2 = .5;
#endif
OMEGA = 0.00013143527; // 1/s
tmax = 2.*M_PI/OMEGA;
G = 6.67428e-11; // N / (1e-5 kg)^2 m^2
softening = 0.1; // m
dt = 1e-2*2.*M_PI/OMEGA; // s
root_nx = 8; root_ny = 8; root_nz = 1;
nghostx = 2; nghosty = 2; nghostz = 0; // Use three ghost rings
double surfacedensity = 418; // kg/m^2
double particle_density = 400; // kg/m^3
double particle_radius_min = 1; // m
double particle_radius_max = 4; // m
double particle_radius_slope = -3;
boxsize = 70.7;
if (argc>1){ // Try to read boxsize from command line
boxsize = atof(argv[1]);
}
init_box();
// Initial conditions
// Use Bridges et al coefficient of restitution.
coefficient_of_restitution_for_velocity = coefficient_of_restitution_bridges;
minimum_collision_velocity = particle_radius_min*OMEGA*0.001; // small fraction of the shear
double total_mass = surfacedensity*boxsize*boxsize;
for(int i=0;i<root_n;i++){
#ifdef MPI
if (communication_mpi_rootbox_is_local(i)==0) continue;
#endif
// Ring particles
double mass = 0;
while(mass<total_mass){
struct particle pt;
int ri = i%root_nx;
int rj = ((i-ri)/root_nx)%root_ny;
int xmin = -boxsize_x/2.+(double)(ri)*boxsize;
int ymin = -boxsize_y/2.+(double)(rj)*boxsize;
pt.x = tools_uniform(xmin,xmin+boxsize);
pt.y = tools_uniform(ymin,ymin+boxsize);
pt.z = tools_normal(1.); // m
pt.vx = 0;
pt.vy = -1.5*pt.x*OMEGA;
pt.vz = 0;
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
double radius = tools_powerlaw(particle_radius_min,particle_radius_max,particle_radius_slope);
#ifndef COLLISIONS_NONE
pt.r = radius; // m
#endif // COLLISIONS_NONE
double particle_mass = particle_density*4./3.*M_PI*radius*radius*radius;
pt.m = particle_mass; // kg
particles_add(pt);
mass += particle_mass;
}
}
}
void problem_init(int argc, char* argv[]){
// Setup constants
#ifdef GRAVITY_TREE
opening_angle2 = .5;
#endif // GRAVITY_TREE
OMEGA = 0.00013143527; // 1/s
G = 6.67428e-11; // N / (1e-5 kg)^2 m^2
softening = 0.1; // m
dt = 1e-3*2.*M_PI/OMEGA; // s
#ifdef OPENGL
display_rotate_z = 20; // Rotate the box by 20 around the z axis, then
display_rotate_x = 60; // rotate the box by 60 degrees around the x axis
#ifdef LIBPNG
system("mkdir png");
#endif // LIBPNG
#endif // OPENGL
root_nx = 2; root_ny = 2; root_nz = 1;
nghostx = 2; nghosty = 2; nghostz = 0; // Use two ghost rings
double surfacedensity = 400; // kg/m^2
double particle_density = 400; // kg/m^3
double particle_radius_min = 1; // m
double particle_radius_max = 4; // m
double particle_radius_slope = -3;
boxsize = 100; // m
if (argc>1){ // Try to read boxsize from command line
boxsize = atof(argv[1]);
}
init_box();
// Initial conditions
printf("Toomre wavelength: %f\n",2.*M_PI*M_PI*surfacedensity/OMEGA/OMEGA*G);
// Use Bridges et al coefficient of restitution.
coefficient_of_restitution_for_velocity = coefficient_of_restitution_bridges;
minimum_collision_velocity = particle_radius_min*OMEGA*0.001; // small fraction of the shear
double total_mass = surfacedensity*boxsize_x*boxsize_y;
double mass = 0;
while(mass<total_mass){
struct particle pt;
pt.x = tools_uniform(-boxsize_x/2.,boxsize_x/2.);
pt.y = tools_uniform(-boxsize_y/2.,boxsize_y/2.);
pt.z = tools_normal(1.); // m
pt.vx = 0;
pt.vy = -1.5*pt.x*OMEGA;
pt.vz = 0;
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
double radius = tools_powerlaw(particle_radius_min,particle_radius_max,particle_radius_slope);
#ifndef COLLISIONS_NONE
pt.r = radius; // m
#endif
double particle_mass = particle_density*4./3.*M_PI*radius*radius*radius;
pt.m = particle_mass; // kg
particles_add(pt);
mass += particle_mass;
}
}
void problem_init(int argc, char* argv[]){
// Setup constants
#ifdef GRAVITY_TREE
opening_angle2 = .5;
#endif
OMEGA = 0.00013143527; // 1/s
G = 6.67428e-11; // N / (1e-5 kg)^2 m^2
softening = 0.1; // m
dt = 1e-3*2.*M_PI/OMEGA; // s
root_nx = 2; root_ny = 2; root_nz = 1;
nghostx = 2; nghosty = 2; nghostz = 0; // Use two ghost rings
double surfacedensity = 400; // kg/m^2
double particle_density = 400; // kg/m^3
double particle_radius_min = 1; // m
double particle_radius_max = 4; // m
double particle_radius_slope = -3;
boxsize = 100;
if (argc>1){ // Try to read boxsize from command line
boxsize = atof(argv[1]);
}
init_box();
// Initial conditions
printf("Toomre wavelength: %f\n",2.*M_PI*M_PI*surfacedensity/OMEGA/OMEGA*G);
// Use Bridges et al coefficient of restitution.
coefficient_of_restitution_for_velocity = coefficient_of_restitution_bridges;
minimum_collision_velocity = particle_radius_min*OMEGA*0.001; // small fraction of the shear
double total_mass = surfacedensity*boxsize_x*boxsize_y;
#ifdef MPI
// Only initialise particles on master. This should also be parallelied but the details depend on the individual problem.
if (mpi_id==0){
#endif
double mass = 0;
while(mass<total_mass){
struct particle pt;
pt.x = tools_uniform(-boxsize_x/2.,boxsize_x/2.);
pt.y = tools_uniform(-boxsize_y/2.,boxsize_y/2.);
pt.z = tools_normal(1.); // m
pt.vx = 0;
pt.vy = -1.5*pt.x*OMEGA;
pt.vz = 0;
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
double radius = tools_powerlaw(particle_radius_min,particle_radius_max,particle_radius_slope);
#ifndef COLLISIONS_NONE
pt.r = radius; // m
#endif
double particle_mass = particle_density*4./3.*M_PI*radius*radius*radius;
pt.m = particle_mass; // kg
particles_add(pt);
mass += particle_mass;
}
#ifdef MPI
}
#endif
}
void problem_init(int argc, char* argv[]){
// Setup constants
OMEGA = 0.00013143527; // 1/s
G = 6.67428e-11; // N / (1e-5 kg)^2 m^2
dt = 1e-3*2.*M_PI/OMEGA; // s
root_nx = 10; root_ny = 1; root_nz = 1;
nghostx = 1; nghosty = 1; nghostz = 0; // Use two one ring (+cutoff, see below)
double surfacedensity = 400; // kg/m^2
double particle_density = 400; // kg/m^3
double particle_radius_min = 1; // m
double particle_radius_max = 4; // m
double particle_radius_slope = -3;
boxsize = 100;
if (argc>1){ // Try to read boxsize from command line
boxsize = atof(argv[1]);
}
init_box();
#ifdef GRAVITY_GRAPE
gravity_range = boxsize/2.;
#endif // GRAVITY_GRAPE
// Initial conditions
printf("Toomre wavelength: %f\n",2.*M_PI*M_PI*surfacedensity/OMEGA/OMEGA*G);
#ifndef COLLISIONS_NONE
// Use Bridges et al coefficient of restitution.
coefficient_of_restitution_for_velocity = coefficient_of_restitution_bridges;
minimum_collision_velocity = particle_radius_min*OMEGA*0.001; // small fraction of the shear
softening = 0.1; // m
#else // COLLISIONS_NONE
softening = particle_radius_max;
#endif // COLLISIONS_NONE
double total_mass = surfacedensity*boxsize_x*boxsize_y;
double mass = 0;
while(mass<total_mass){
struct particle pt;
pt.x = tools_uniform(-boxsize_x/2.,boxsize_x/2.);
pt.y = tools_uniform(-boxsize_y/2.,boxsize_y/2.);
pt.z = tools_normal(1.); // m
pt.vx = 0;
pt.vy = -1.5*pt.x*OMEGA;
pt.vz = 0;
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
double radius = tools_powerlaw(particle_radius_min,particle_radius_max,particle_radius_slope);
#ifndef COLLISIONS_NONE
pt.r = radius; // m
#endif
double particle_mass = particle_density*4./3.*M_PI*radius*radius*radius;
pt.m = particle_mass; // kg
particles_add(pt);
mass += particle_mass;
}
}
void problem_init(int argc, char* argv[]){
// Setup constants
#ifdef GRAVITY_TREE
opening_angle2 = .5;
#endif // GRAVITY_TREE
integrator = SEI;
OMEGA = 0.00013143527; // 1/s
G = 6.67428e-11; // N / (1e-5 kg)^2 m^2
softening = 0.1; // m
dt = 1e-3*2.*M_PI/OMEGA; // s
root_nx = 2; root_ny = 2; root_nz = 1;
nghostx = 2; nghosty = 2; nghostz = 0; // Use two ghost rings
double surfacedensity = 840; // kg/m^2
double particle_density = 900; // kg/m^3
double particle_radius_min = 1.; // m
double particle_radius_max = 1.; // m
double particle_radius_slope = -3;
boxsize = 40; // m
if (argc>1){ // Try to read boxsize from command line
boxsize = atof(argv[1]);
}
init_box();
// Initial conditions
printf("Toomre wavelength: %f\n",4.*M_PI*M_PI*surfacedensity/OMEGA/OMEGA*G);
// Use Bridges et al coefficient of restitution.
coefficient_of_restitution_for_velocity = coefficient_of_restitution_bridges;
// Change collision_resolve routing from default.
collision_resolve = collision_resolve_hardsphere_pullaway;
// Small residual velocity to avoid particles from sinking into each other.
minimum_collision_velocity = particle_radius_min*OMEGA*0.001; // small fraction of the shear
double total_mass = surfacedensity*boxsize_x*boxsize_y;
double mass = 0;
while(mass<total_mass){
struct particle pt;
pt.x = tools_uniform(-boxsize_x/2.,boxsize_x/2.);
pt.y = tools_uniform(-boxsize_y/2.,boxsize_y/2.);
pt.z = tools_normal(1.); // m
pt.vx = 0;
pt.vy = -1.5*pt.x*OMEGA;
pt.vz = 0;
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
double radius = tools_powerlaw(particle_radius_min,particle_radius_max,particle_radius_slope);
#ifndef COLLISIONS_NONE
pt.r = radius; // m
#endif
double particle_mass = particle_density*4./3.*M_PI*radius*radius*radius;
pt.m = particle_mass; // kg
particles_add(pt);
mass += particle_mass;
}
}
void problem_init(int argc, char* argv[]){
// Setup constants
opening_angle2 = 1.5; // This constant determines the accuracy of the tree code gravity estimate.
G = 1;
softening = 0.01; // Gravitational softening length
dt = 3e-3; // Timestep
boxsize = 1.2; // Particles outside the box are removed
root_nx = 1; root_ny = 1; root_nz = 1;
nghostx = 0; nghosty = 0; nghostz = 0;
init_box();
// Setup particles
double disc_mass = 2e-1; // Total disc mass
int _N = 10000; // Number of particles
// Initial conditions
struct particle star;
star.x = 0; star.y = 0; star.z = 0;
star.vx = 0; star.vy = 0; star.vz = 0;
star.ax = 0; star.ay = 0; star.az = 0;
star.m = 1;
#ifdef INTEGRATOR_WH
// Insert particle manually. Don't add it to tree.
Nmax += 128;
particles = realloc(particles,sizeof(struct particle)*Nmax);
particles[N] = star;
N++;
#else // INTEGRATOR_WH
particles_add(star);
#endif // INTEGRATOR_WH
while(N<_N){
struct particle pt;
double a = tools_powerlaw(boxsize/10.,boxsize/2./1.2,-1.5);
double phi = tools_uniform(0,2.*M_PI);
pt.x = a*cos(phi);
pt.y = a*sin(phi);
pt.z = a*tools_normal(0.001);
double mu = star.m + disc_mass * (pow(a,-3./2.)-pow(boxsize/10.,-3./2.))/(pow(boxsize/2./1.2,-3./2.)-pow(boxsize/10.,-3./2.));
double vkep = sqrt(G*mu/a);
pt.vx = vkep * sin(phi);
pt.vy = -vkep * cos(phi);
pt.vz = 0;
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
pt.m = disc_mass/(double)_N;
particles_add(pt);
}
}
void problem_init(int argc, char* argv[]){
// Setup constants
G = 1;
integrator = LEAPFROG;
softening = 0.01;
dt = 3e-3;
boxsize = 1.2;
root_nx = 1; root_ny = 1; root_nz = 1;
nghostx = 0; nghosty = 0; nghostz = 0;
init_box();
// Setup particles
double disc_mass = 2e-1;
int _N = 10000;
// Initial conditions
struct particle star;
star.x = 0; star.y = 0; star.z = 0;
star.vx = 0; star.vy = 0; star.vz = 0;
star.ax = 0; star.ay = 0; star.az = 0;
star.m = 1;
#ifdef INTEGRATOR_WH
// Insert particle manually. Don't add it to tree.
Nmax += 128;
particles = realloc(particles,sizeof(struct particle)*Nmax);
particles[N] = star;
N++;
#else // INTEGRATOR_WH
particles_add(star);
#endif // INTEGRATOR_WH
while(N<_N){
struct particle pt;
double a = tools_powerlaw(boxsize/10.,boxsize/2./1.2,-1.5);
double phi = tools_uniform(0,2.*M_PI);
pt.x = a*cos(phi);
pt.y = a*sin(phi);
pt.z = a*tools_normal(0.001);
double mu = star.m + disc_mass * (pow(a,-3./2.)-pow(boxsize/10.,-3./2.))/(pow(boxsize/2./1.2,-3./2.)-pow(boxsize/10.,-3./2.));
double vkep = sqrt(G*mu/a);
pt.vx = vkep * sin(phi);
pt.vy = -vkep * cos(phi);
pt.vz = 0;
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
pt.m = disc_mass/(double)_N;
particles_add(pt);
}
}
void problem_init(int argc, char* argv[]){
// Setup constants
integrator = WH;
G = 1;
N_active = 1;
N_collisions = 1; // Don't detect collisions for the star.
softening = 0.01;
dt = 1e-3;
boxsize = 2.4;
root_nx = 1; root_ny = 1; root_nz = 1;
nghostx = 0; nghosty = 0; nghostz = 0;
init_box();
// Setup particles
int _N = 1000;
// Initial conditions
struct particle star;
star.x = 0; star.y = 0; star.z = 0;
star.vx = 0; star.vy = 0; star.vz = 0;
star.ax = 0; star.ay = 0; star.az = 0;
star.m = 1;
star.r = 0.01;
particles_add(star);
while(N<_N){
struct particle pt;
double a = tools_powerlaw(boxsize/2.9,boxsize/3.1,.5);
double phi = tools_uniform(0,2.*M_PI);
pt.x = a*cos(phi);
pt.y = a*sin(phi);
pt.z = a*tools_normal(0.0001);
double vkep = sqrt(G*star.m/a);
pt.vx = vkep * sin(phi);
pt.vy = -vkep * cos(phi);
pt.vz = 0;
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
pt.m = 0.0001;
pt.r = .3/sqrt((double)_N);
particles_add(pt);
}
}
void problem_init(int argc, char* argv[]){
// Setup constants
G = 1;
softening = 0.01;
dt = 3e-3;
boxsize = 2.4;
integrator = LEAPFROG;
root_nx = 1; root_ny = 1; root_nz = 1;
nghostx = 0; nghosty = 0; nghostz = 0;
init_box();
// Initial conditions
struct particle star;
star.x = 0; star.y = 0; star.z = 0;
star.vx = 0; star.vy = 0; star.vz = 0;
star.ax = 0; star.ay = 0; star.az = 0;
star.m = 1;
particles_add(star);
// Setup disk particles
double disc_mass = 2e-1;
int _N = 1024*4;
while(N<_N){
struct particle pt;
double a = tools_powerlaw(boxsize/20.,boxsize/4./1.2,-1.5);
double phi = tools_uniform(0,2.*M_PI);
pt.x = a*cos(phi);
pt.y = a*sin(phi);
pt.z = a*tools_normal(0.001);
double mu = star.m + disc_mass * (pow(a,-3./2.)-pow(boxsize/20.,-3./2.))/(pow(boxsize/4./1.2,-3./2.)-pow(boxsize/20.,-3./2.));
double vkep = sqrt(G*mu/a);
pt.vx = vkep * sin(phi);
pt.vy = -vkep * cos(phi);
pt.vz = 0;
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
pt.m = disc_mass/(double)_N;
particles_add(pt);
}
}
void problem_init(int argc, char* argv[]) {
// Setup constants
double radius = 1;
double mass = 1;
dt = 1e-1;
integrator = LEAPFROG;
// Override default collision handling to account for border particles
coefficient_of_restitution = 0.15;
collision_resolve = collision_resolve_hardsphere_withborder;
root_nx = 1;
root_ny = 1;
root_nz = 4;
nghostx = 1;
nghosty = 1;
nghostz = 0;
boxsize = 20;
init_box();
double N_part = 0.00937*boxsize_x*boxsize_y*boxsize_z;
// Add Border Particles
double border_spacing_x = boxsize_x/(floor(boxsize_x/radius/2.)-1.);
double border_spacing_y = boxsize_y/(floor(boxsize_y/radius/2.)-1.);
struct particle pt;
pt.vx = 0;
pt.vz = 0;
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
pt.r = radius;
pt.m = mass;
for(double x = -boxsize_x/2.; x<boxsize_x/2.-border_spacing_x/2.; x+=border_spacing_x) {
for(double y = -boxsize_y/2.; y<boxsize_y/2.-border_spacing_y/2.; y+=border_spacing_y) {
pt.x = x;
pt.y = y;
// Add particle to bottom
pt.z = -boxsize_z/2.+radius;
pt.vy = 1;
particles_add(pt);
// Add particle to top
pt.z = boxsize_z/2.-radius;
pt.vy = -1;
particles_add(pt);
N_tree_fixed++;
}
}
N_border = N;
#ifdef TREE
N_tree_fixed = N_border;
#endif // TREE
// Add real particles
while(N-N_border<N_part) {
struct particle pt;
pt.x = tools_uniform(-boxsize_x/2.,boxsize_x/2.);
pt.y = tools_uniform(-boxsize_y/2.,boxsize_y/2.);
pt.z = 0.758*tools_uniform(-boxsize_z/2.,boxsize_z/2.);
pt.vx = tools_normal(0.001);
pt.vy = tools_normal(0.001);
pt.vz = tools_normal(0.001);
pt.ax = 0;
pt.ay = 0;
pt.az = 0;
pt.r = radius; // m
pt.m = 1;
particles_add(pt);
}
}
