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Coryab/implement penning trap simulate #6

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coryab merged 16 commits from coryab/implement-PenningTrap-simulate into develop 2023-10-14 01:13:37 +00:00
Conversation 0 Commits 16 Files Changed 117 +63 -79
3 changed files with 63 additions and 79 deletions
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4
include/PenningTrap.hpp
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@ -36,6 +36,10 @@ private:
double V_0; ///< Applied potential
double d; ///< Characteristic dimension
std::vector<Particle> particles; ///< The particles in the Penning trap
arma::vec::fixed<3> *k_v;
arma::vec::fixed<3> *k_r;
std::function<arma::vec(int, double)> v_funcs[4];
std::function<arma::vec(int, double)> r_funcs[4];
public:
/** @brief Set B_0, V_0 and d.

138
src/PenningTrap.cpp
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@ -26,28 +26,51 @@ PenningTrap::PenningTrap(double B_0, double V_0, double d)
this->B_0 = B_0;
this->V_0 = V_0;
this->d = d;
v_funcs[0] = [this](int i, double dt) { return .5 * dt * this->k_v[i]; };
v_funcs[1] = [this](int i, double dt) {
return .5 * dt * this->k_v[this->particles.size() + i];
};
v_funcs[2] = [this](int i, double dt) {
return dt * this->k_v[2 * this->particles.size() + i];
};
v_funcs[3] = [this](int i, double dt) {
arma::vec res = this->k_v[i] + this->k_v[this->particles.size() + i] +
this->k_v[2 * this->particles.size() + i] +
this->k_v[3 * this->particles.size() + i];
return (dt / 6) * res;
};
r_funcs[0] = [this](int i, double dt) { return .5 * dt * this->k_r[i]; };
r_funcs[1] = [this](int i, double dt) {
return .5 * dt * this->k_r[this->particles.size() + i];
};
r_funcs[2] = [this](int i, double dt) {
return dt * this->k_r[2 * this->particles.size() + i];
};
r_funcs[3] = [this](int i, double dt) {
arma::vec res = this->k_r[i] + this->k_r[this->particles.size() + i] +
this->k_r[2 * this->particles.size() + i] +
this->k_r[3 * this->particles.size() + i];
return (dt / 6) * res;
};
}
PenningTrap::PenningTrap(int i, double B_0, double V_0, double d)
: PenningTrap::PenningTrap(B_0, V_0, d)
{
this->B_0 = B_0;
this->V_0 = V_0;
this->d = d;
arma::vec r, v;
for (int j = 0; j < i; j++) {
r = arma::vec(3).randn() * .1 * this->d;
v = arma::vec(3).randn() * .1 * this->d;
r = arma::vec::fixed<3>().randn() * .1 * this->d;
v = arma::vec::fixed<3>().randn() * .1 * this->d;
this->add_particle(Particle(1., 40., r, v));
}
}
PenningTrap::PenningTrap(std::vector<Particle> particles, double B_0,
double V_0, double d)
: PenningTrap::PenningTrap(B_0, V_0, d)
{
this->B_0 = B_0;
this->V_0 = V_0;
this->d = d;
this->particles = particles;
}
@ -58,11 +81,8 @@ void PenningTrap::add_particle(Particle particle)
arma::vec PenningTrap::external_E_field(arma::vec r)
{
arma::vec::fixed<3> res;
arma::vec::fixed<3> res{r(0), r(1), -2. * r(2)};
double f = this->V_0 / (this->d * this->d);
res(0) = r(0);
res(1) = r(1);
res(2) = -2. * r(2);
return f * res;
}
@ -91,6 +111,10 @@ arma::vec PenningTrap::force_on_particle(int i, int j)
arma::vec PenningTrap::total_force_external(int i)
{
if (arma::norm(this->particles.at(i).r_vec) > this->d) {
return arma::vec::fixed<3>{0., 0., 0.};
}
Particle p = this->particles.at(i);
arma::vec::fixed<3> B = this->external_B_field(p.r_vec);
@ -99,7 +123,8 @@ arma::vec PenningTrap::total_force_external(int i)
p.v_vec(2) * B(0) - p.v_vec(0) * B(2),
p.v_vec(0) * B(1) - p.v_vec(1) * B(0)};
arma::vec force = p.q * (this->external_E_field(p.r_vec) + v_cross_B);
arma::vec::fixed<3> force =
p.q * (this->external_E_field(p.r_vec) + v_cross_B);
return force;
}
@ -108,7 +133,7 @@ arma::vec PenningTrap::total_force_particles(int i)
{
Particle p = this->particles.at(i);
arma::vec res(3);
arma::vec::fixed<3> res;
for (int j = 0; j < this->particles.size(); j++) {
if (i == j) {
@ -131,81 +156,34 @@ arma::vec PenningTrap::total_force(int i)
void PenningTrap::evolve_RK4(double dt, bool particle_interaction)
{
std::vector<Particle> original_particles = this->particles;
std::vector<Particle> tmp_particles = this->particles;
std::function<arma::vec(int)> force;
if (particle_interaction) {
force = [this](int i) {
return this->total_force(i);
};
force = [this](int i) { return this->total_force(i); };
}
else {
force = [this](int i) {
return this->total_force_external(i);
};
force = [this](int i) { return this->total_force_external(i); };
}
arma::vec::fixed<3> *k_v =
new arma::vec::fixed<3>[this->particles.size() * 4];
arma::vec::fixed<3> *k_r =
new arma::vec::fixed<3>[this->particles.size() * 4];
int size = this->particles.size();
for (int i = 0; i < size; i++) {
k_v[i] = this->total_force(i) / this->particles.at(i).m;
k_r[i] = this->particles.at(i).v_vec;
k_v = new arma::vec::fixed<3>[size * 4];
k_r = new arma::vec::fixed<3>[size * 4];
for (int i = 0; i < 4; i++) {
#pragma omp parallel for
for (int j = 0; j < size; j++) {
k_v[i * size + j] = this->total_force(j) / this->particles.at(j).m;
k_r[i * size + j] = this->particles.at(j).v_vec;
Particle *p = &tmp_particles.at(j);
p->v_vec = original_particles.at(j).v_vec + this->v_funcs[i](j, dt);
p->r_vec = original_particles.at(j).r_vec + this->r_funcs[i](j, dt);
}
for (int i = 0; i < size; i++) {
Particle *p = &this->particles.at(i);
p->v_vec = tmp_particles.at(i).v_vec + (dt / 2) * k_v[i];
p->r_vec = tmp_particles.at(i).r_vec + (dt / 2) * k_r[i];
}
for (int i = 0; i < size; i++) {
k_v[1 * size + i] = this->total_force(i) / this->particles.at(i).m;
k_r[1 * size + i] = this->particles.at(i).v_vec;
}
for (int i = 0; i < size; i++) {
Particle *p = &this->particles.at(i);
p->v_vec = tmp_particles.at(i).v_vec + (dt / 2) * k_v[1 * size + i];
p->r_vec = tmp_particles.at(i).r_vec + (dt / 2) * k_r[1 * size + i];
}
for (int i = 0; i < size; i++) {
k_v[2 * size + i] = this->total_force(i) / this->particles.at(i).m;
k_r[2 * size + i] = this->particles.at(i).v_vec;
}
for (int i = 0; i < size; i++) {
Particle *p = &this->particles.at(i);
p->v_vec = tmp_particles.at(i).v_vec + dt * k_v[2 * size + i];
p->r_vec = tmp_particles.at(i).r_vec + dt * k_r[2 * size + i];
}
for (int i = 0; i < size; i++) {
k_v[3 * size + i] = this->total_force(i) / this->particles.at(i).m;
k_r[3 * size + i] = this->particles.at(i).v_vec;
}
for (int i = 0; i < size; i++) {
Particle *p = &this->particles.at(i);
p->v_vec = tmp_particles.at(i).v_vec +
dt *
(k_v[i] + k_v[size + i] + k_v[2 * size + i] +
k_v[3 * size + i]) /
6;
p->r_vec = tmp_particles.at(i).r_vec +
dt *
(k_r[i] + k_r[size + i] + k_r[2 * size + i] +
k_r[3 * size + i]) /
6;
this->particles = tmp_particles;
}
delete[] k_v;
@ -259,6 +237,7 @@ sim_arr PenningTrap::simulate(double time, int steps, std::string method,
}
for (int j = 0; j < steps; j++) {
#pragma omp parallel for
for (int i = 0; i < this->particles.size(); i++) {
res[i][j] = this->particles[i].r_vec;
}
@ -287,6 +266,7 @@ void PenningTrap::write_simulation_to_dir(std::string path, double time,
std::ofstream ofile;
sim_rows row;
#pragma omp parallel for private(ofile, row)
for (int i = 0; i < number_of_particles; i++) {
row = res[i];
ofile.open(path + "particle_" + std::to_string(i) + ".txt");

4
src/animate_100_particles.py
View File

@ -63,8 +63,8 @@ def animate():
fig, update, N, fargs=(lines, arr), interval=1, blit=False
)
ani.save("../images/100_particles.gif", writer=animation.FFMpegFileWriter(fps=50))
# plt.show()
# ani.save("../images/100_particles.gif", writer=animation.FFMpegFileWriter(fps=50))
plt.show()
if __name__ == "__main__":