228 lines
7.4 KiB
C++
228 lines
7.4 KiB
C++
/** @file PenningTrap.hpp
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*
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* @author Cory Alexander Balaton (coryab)
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* @author Janita Ovidie Sandtrøen Willumsen (janitaws)
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*
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* @version 0.1
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*
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* @brief A class for simulating a Penning trap.
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*
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* @bug No known bugs
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* */
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#ifndef __PENNING_TRAP__
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#define __PENNING_TRAP__
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#include <armadillo>
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#include <omp.h>
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#include "Particle.hpp"
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#include "constants.hpp"
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#include "typedefs.hpp"
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#pragma omp declare reduction(+ : vec_3d : omp_out += omp_in) \
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initializer(omp_priv = omp_orig)
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typedef struct simulation {
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sim_arr r_vecs;
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sim_arr v_vecs;
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} simulation_t;
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/** @brief A class that simulates a Penning trap.
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*
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* This class simulates a Penning trap. It can take in a number of particles
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* and simulate how they would behave inside a Penning trap.
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* */
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class PenningTrap {
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private:
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double B_0; ///< Magnetic field strength
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std::function<double(double)> V_0; ///< Applied potential
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double d; ///< Characteristic dimension
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double t; ///< Current time
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std::vector<Particle> particles; ///< The particles in the Penning trap
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sim_arr k_v; ///< A 2D vector containing all \f$k_{i,j}\f$ where \f$j\f$ is
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///< the index of a particle
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sim_arr k_r; ///< A 2D vector containing all \f$k_{i,j}\f$ where \f$j\f$ is
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///< the index of a particle
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/** @brief Helper for evolve_RK4 when calculating \f$k_{v,i,j}\f$ values
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*
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* @details Something
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*
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* @param i Index i for \f$k_{v,i,j}\f$
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* @param j Index j for \f$k_{v,i,j}\f$
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* @param dt the step length (delta time)
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*
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* @return vec_3d
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* */
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vec_3d v_func(unsigned int i, unsigned int j, double dt);
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/** @brief Helper for evolve_RK4 when calculating \f$k_{r,i,j}\f$ values
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*
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* @details Something
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*
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* @param i Index i for \f$k_{r,i,j}\f$
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* @param j Index j for \f$k_{r,i,j}\f$
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* @param dt the step length (delta time)
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*
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* @return vec_3d
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* */
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vec_3d r_func(unsigned int i, unsigned int j, double dt);
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public:
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/** @brief Constructor for the PenningTrap class
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*
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* @param B_0 The magnetic field strength
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* @param V_0 The time dependent applied potential
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* @param d The characteristic dimension
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* @param t The starting time
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* */
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PenningTrap(
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double B_0 = T,
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std::function<double(double)> V_0 =
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[](double t) { return 25. * V / 1000.; },
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double d = 500., double t = 0.);
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/** @brief Constructor for the PenningTrap class
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*
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* @param i The number of particles to generate
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* @param B_0 The magnetic field strength
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* @param V_0 The time dependent applied potential
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* @param d The characteristic dimension
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* @param t The starting time
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* */
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PenningTrap(
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unsigned int i, double B_0 = T,
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std::function<double(double)> V_0 =
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[](double t) { return 25. * V / 1000.; },
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double d = 500., double t = 0.);
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/** @brief Constructor for the PenningTrap class
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*
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* @param particles The starting particles
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* @param B_0 The magnetic field strength
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* @param V_0 The time dependent applied potential
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* @param d The characteristic dimension
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* @param t The starting time
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* */
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PenningTrap(
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std::vector<Particle> particles, double B_0 = T,
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std::function<double(double)> V_0 =
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[](double t) { return 25. * V / 1000.; },
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double d = 500., double t = 0.);
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/** @brief Add a particle to the system
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*
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* @param particle The particle to add to the Penning trap
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* */
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void add_particle(Particle particle);
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/** @brief Calculate E at point r
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*
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* @param r The position where we want to calculate the E field
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*
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* @return vec_3d
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* */
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vec_3d external_E_field(vec_3d r);
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/** @brief Calculate B at point r
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*
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* @param r The position where we want to calculate the B field
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*
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* @return vec_3d
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* */
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vec_3d external_B_field(vec_3d r);
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/** @brief Calculate the force between 2 particles.
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*
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* @details Calculate the force exhibited on particle p_i from
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* particle p_j.
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*
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* @param i The index of particle p_i
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* @param j The index of particle p_j
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*
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* @return vec_3d
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* */
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vec_3d force_on_particle(unsigned int i, unsigned int j);
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/** @brief Calculate the total external force on a particle.
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*
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* @details Calculate the total amount of force that E and B exhibits
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* on particle p_i.
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*
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* @param i The index of particle p_i
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*
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* @return vec_3d
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* */
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vec_3d total_force_external(unsigned int i);
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/** @brief Calculate the total force on a particle p_i from other particles.
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*
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* @param i The index of particle p_i
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*
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* @return vec_3d
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* */
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vec_3d total_force_particles(unsigned int i);
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/** @brief calculate the total force on a particle p_i.
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*
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* @param i The index of particle p_i
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*
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* @return vec_3d
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* */
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vec_3d total_force(unsigned int i);
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/** @brief Go forward one timestep using the RK4 method
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*
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* @param dt The step length
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* @param particle_interaction Turn particle interactions on/off
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* */
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void evolve_RK4(double dt, bool particle_interaction = true);
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/** @brief Go forward one timestep using the forward Euler method
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*
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* @param dt The step length
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* @param particle_interaction Turn particle interactions on/off
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* */
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void evolve_forward_euler(double dt, bool particle_interaction = true);
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/** @brief Simulate the particle system inside the Penning trap over
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* a certain amount of time.
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*
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* @param time The time to simulate in microseconds
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* @param steps The amount of steps for the whole simulation
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* @param method The method to use when moving forward a timestep
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* @param particle_interaction Turn particle interactions on/off
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* */
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simulation_t simulate(double time, unsigned int steps,
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std::string method = "rk4",
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bool particle_interaction = true);
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/** @brief Simulate and write the displacement of all particles to files.
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*
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* @param path The directory to save the data
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* @param time The time to simulate in microseconds
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* @param steps The amount of steps for the whole simulation
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* @param method The method to use when moving forward a timestep
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* @param particle_interaction Turn particle interactions on/off
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* */
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void write_simulation_to_dir(std::string path, double time,
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unsigned int steps, std::string method = "rk4",
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bool particle_interaction = true);
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/** @brief Simulate and calculate what fraction of particles are still
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* left inside the Penning trap after the simulation.
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*
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* @param time The time to simulate in microseconds
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* @param steps The amount of steps for the whole simulation
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* @param method The method to use when moving forward a timestep
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* @param particle_interaction Turn particle interactions on/off
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*
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* @return double
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* */
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double fraction_of_particles_left(double time, unsigned int steps,
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std::string method = "rk4",
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bool particle_interaction = true);
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};
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#endif
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