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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 +86 -38
2 changed files with 86 additions and 38 deletions
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22
include/PenningTrap.hpp
View File

@ -18,8 +18,12 @@
#include "Particle.hpp"
#include "constants.hpp"
#pragma omp declare reduction( + : arma::vec : omp_out += omp_in ) \
initializer( omp_priv = omp_orig )
typedef std::vector<arma::vec::fixed<3>> sim_cols;
typedef std::vector<arma::vec::fixed<3>> sim_rows;
typedef std::vector<sim_cols> sim_arr;
#pragma omp declare reduction(+ : arma::vec : omp_out += omp_in) \
initializer(omp_priv = omp_orig)
/** @brief A class that simulates a Penning trap.
*
@ -28,15 +32,15 @@
* */
class PenningTrap {
private:
double B_0; ///< Magnetic field strength
double V_0; ///< Applied potential
double d; ///< Characteristic dimension
double B_0; ///< Magnetic field strength
double V_0; ///< Applied potential
double d; ///< Characteristic dimension
std::vector<Particle> particles; ///< The particles in the Penning trap
public:
/** @brief Set B_0, V_0 and d.
* */
PenningTrap(double B_0 = T, double V_0 = 25.*V/1000., double d = 500.);
PenningTrap(double B_0 = T, double V_0 = 25. * V / 1000., double d = 500.);
/** @brief Add a particle to the system
* */
@ -52,7 +56,7 @@ public:
/** @brief Calculate the force between 2 particles.
*
* @details Calculate the force exhibited on particle p_i from
* @details Calculate the force exhibited on particle p_i from
* particle p_j.
* */
arma::vec force_on_particle(int i, int j);
@ -69,7 +73,7 @@ public:
arma::vec total_force_particles(int i);
/** @brief calculate the total force on a particle.
* */
* */
arma::vec total_force(int i);
/** @brief Go forward one timestep using the RK4 method
@ -80,6 +84,8 @@ public:
* */
void evolve_forward_euler(double dt);
sim_arr simulate(double time, int steps, std::string method = "rk4");
arma::vec get_particle(int i);
double get_d();

102
src/PenningTrap.cpp
View File

@ -16,6 +16,7 @@
#include "PenningTrap.hpp"
#include "constants.hpp"
#include "utils.hpp"
#include <cstdlib>
PenningTrap::PenningTrap(double B_0, double V_0, double d)
{
@ -104,64 +105,72 @@ arma::vec PenningTrap::total_force(int i)
void PenningTrap::evolve_RK4(double dt)
{
std::vector<Particle> tmp_particles = this->particles;
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];
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;
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;
}
for (int i=0; i<size; i++) {
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];
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++) {
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++) {
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];
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++) {
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++) {
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];
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++) {
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++) {
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;
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;
}
delete [] k_v;
delete [] k_r;
delete[] k_v;
delete[] k_r;
}
void PenningTrap::evolve_forward_euler(double dt)
@ -180,6 +189,39 @@ void PenningTrap::evolve_forward_euler(double dt)
this->particles = new_state;
}
sim_arr PenningTrap::simulate(double time, int steps, std::string method)
{
double dt = time / (double)steps;
sim_arr res(this->particles.size(), sim_cols(steps));
std::function<void(double)> func;
if (method == "rk4") {
func = [this](double dt) {
this->evolve_RK4(dt);
};
}
else if(method == "euler") {
func = [this](double dt) {
this->evolve_forward_euler(dt);
};
}
else {
std::cout << "Not a valid method!" << std::endl;
abort();
}
int size = this->particles.size();
for (int j=0; j<steps; j++) {
for (int i=0;i<size;i++) {
res[i][j] = this->particles[i].r_vec;
}
func(dt);
}
return res;
}
arma::vec PenningTrap::get_particle(int i)
{
return this->particles.at(i).r_vec;