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Cory Balaton 2023-10-19 13:17:08 +02:00
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commit d9f9940451
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@ -13,10 +13,8 @@
#include <cmath> #include <cmath>
#include <complex> #include <complex>
#include <fstream> #include <fstream>
#include <functional>
#include <omp.h> #include <omp.h>
#include <string> #include <string>
#include <sys/stat.h>
#include <vector> #include <vector>
#include "PenningTrap.hpp" #include "PenningTrap.hpp"
@ -24,9 +22,10 @@
#define PARTICLES 100 #define PARTICLES 100
#define N 40000 #define N 40000
#define CHARGE 1. #define CHARGE 1. // unit: e
#define MASS 40. // unit: amu #define MASS 40. // unit: amu
// Particles used for testing
Particle p1(CHARGE, MASS, vec_3d{20., 0., 20.}, vec_3d{0., 25., 0.}); Particle p1(CHARGE, MASS, vec_3d{20., 0., 20.}, vec_3d{0., 25., 0.});
Particle p2(CHARGE, MASS, vec_3d{25., 25., 0.}, vec_3d{0., 40., 5.}); Particle p2(CHARGE, MASS, vec_3d{25., 25., 0.}, vec_3d{0., 40., 5.});
@ -38,7 +37,8 @@ vec_3d analytical_solution_particle_1(double t)
double w_n = (w_0 - std::sqrt(w_0 * w_0 - 2. * w_z2)) / 2.; double w_n = (w_0 - std::sqrt(w_0 * w_0 - 2. * w_z2)) / 2.;
double A_p = (25. + w_n * 20.) / (w_n - w_p); double A_p = (25. + w_n * 20.) / (w_n - w_p);
double A_n = -(25. + w_p * 20.) / (w_n - w_p); double A_n = -(25. + w_p * 20.) / (w_n - w_p);
std::complex<double> f = A_p * std::exp(std::complex<double>(0., -w_p * t)) + std::complex<double> f =
A_p * std::exp(std::complex<double>(0., -w_p * t)) +
A_n * std::exp(std::complex<double>(0., -w_n * t)); A_n * std::exp(std::complex<double>(0., -w_n * t));
vec_3d res{std::real(f), std::imag(f), 20. * std::cos(std::sqrt(w_z2) * t)}; vec_3d res{std::real(f), std::imag(f), 20. * std::cos(std::sqrt(w_z2) * t)};
return res; return res;
@ -46,23 +46,25 @@ vec_3d analytical_solution_particle_1(double t)
void simulate_single_particle() void simulate_single_particle()
{ {
DEBUG("Inside single particle sim"); // Initialize trap with particle 1
PenningTrap trap(std::vector<Particle>{p1}); PenningTrap trap(std::vector<Particle>{p1});
double time = 50.; // microseconds double time = 50.; // microseconds
DEBUG("Write to dir"); // Simulate and write results to file
trap.write_simulation_to_dir("output/simulate_single_particle", time, N, trap.write_simulation_to_dir("output/simulate_single_particle", time, N,
"rk4", false); "rk4", false);
} }
void simulate_two_particles() void simulate_two_particles()
{ {
// Initialize traps with particles
PenningTrap trap_no_interaction(std::vector<Particle>{p1, p2}); PenningTrap trap_no_interaction(std::vector<Particle>{p1, p2});
PenningTrap trap_with_interaction(std::vector<Particle>{p1, p2}); PenningTrap trap_with_interaction(std::vector<Particle>{p1, p2});
double time = 50.; // microseconds double time = 50.; // microseconds
// Simulate and write results to files
trap_no_interaction.write_simulation_to_dir( trap_no_interaction.write_simulation_to_dir(
"output/simulate_2_particles/no_interaction", time, N, "rk4", false); "output/simulate_2_particles/no_interaction", time, N, "rk4", false);
trap_with_interaction.write_simulation_to_dir( trap_with_interaction.write_simulation_to_dir(
@ -71,38 +73,39 @@ void simulate_two_particles()
void simulate_single_particle_with_different_steps() void simulate_single_particle_with_different_steps()
{ {
double time = 50.; // microseconds double time = 50.; // microseconds
std::ofstream ofile; std::ofstream ofile;
// Calculate relative error for RK4
std::string path = "output/relative_error/RK4/";
mkpath(path);
for (int i = 0; i < 4; i++) { for (int i = 0; i < 4; i++) {
int steps = 4000 * std::pow(2, i); int steps = 4000 * std::pow(2, i);
double dt = time / (double)steps; double dt = time / (double)steps;
std::string path = "output/relative_error/RK4/";
mkpath(path);
ofile.open(path + std::to_string(steps) + "_steps.txt"); ofile.open(path + std::to_string(steps) + "_steps.txt");
PenningTrap trap(std::vector<Particle>{p1}); PenningTrap trap(std::vector<Particle>{p1});
simulation_t res = trap.simulate(time, steps, "rk4", false);
for (int i = 0; i < steps; i++) { for (int i = 0; i < steps; i++) {
trap.evolve_RK4(dt); ofile << arma::norm(res.r_vecs[0][i] -
ofile << arma::norm(trap.get_r(0) - analytical_solution_particle_1(dt*i))
analytical_solution_particle_1(trap.get_t()))
<< "\n"; << "\n";
} }
ofile.close(); ofile.close();
} }
// Calculate relative error for forward Euler
path = "output/relative_error/euler/";
mkpath(path);
for (int i = 0; i < 4; i++) { for (int i = 0; i < 4; i++) {
int steps = 4000 * std::pow(2, i); int steps = 4000 * std::pow(2, i);
double dt = time / (double)steps; double dt = time / (double)steps;
std::string path = "output/relative_error/euler/";
mkpath(path);
ofile.open(path + std::to_string(steps) + "_steps.txt"); ofile.open(path + std::to_string(steps) + "_steps.txt");
PenningTrap trap(std::vector<Particle>{p1}); PenningTrap trap(std::vector<Particle>{p1});
simulation_t res = trap.simulate(time, steps, "euler", false);
for (int i = 0; i < steps; i++) { for (int i = 0; i < steps; i++) {
trap.evolve_forward_euler(dt); ofile << arma::norm(res.r_vecs[0][i] -
ofile << arma::norm(trap.get_r(0) - analytical_solution_particle_1(dt*i))
analytical_solution_particle_1(trap.get_t()))
<< "\n"; << "\n";
} }
ofile.close(); ofile.close();
@ -111,19 +114,18 @@ void simulate_single_particle_with_different_steps()
void simulate_100_particles() void simulate_100_particles()
{ {
PenningTrap trap((unsigned)100, T, PenningTrap trap((unsigned)100);
[](double t) {
return 25. * V / 1000. * (1. + .4 * std::cos(1.5 * t));
},
500., 0);
double time = 500.; // microseconds double time = 50.; // microseconds
trap.write_simulation_to_dir("output/simulate_100_particles", time, N * 4); trap.write_simulation_to_dir("output/simulate_100_particles", time, N, "rk4", false);
} }
// Wide sweep
void simulate_100_particles_with_time_potential() void simulate_100_particles_with_time_potential()
{ {
double time = 500.;
double amplitudes[]{.1, .4, .7}; double amplitudes[]{.1, .4, .7};
double freq_start = .2; double freq_start = .2;
@ -156,7 +158,7 @@ void simulate_100_particles_with_time_potential()
amplitudes[i], res[0][j], std::placeholders::_1), amplitudes[i], res[0][j], std::placeholders::_1),
500., 0.); 500., 0.);
res[i + 1][j] = res[i + 1][j] =
trap.fraction_of_particles_left(500., 40000, "rk4", false); trap.fraction_of_particles_left(time, N, "rk4", false);
} }
} }
@ -170,21 +172,23 @@ void simulate_100_particles_with_time_potential()
int main() int main()
{ {
double start = omp_get_wtime(); double t0 = omp_get_wtime();
simulate_single_particle(); // simulate_single_particle();
simulate_two_particles(); // simulate_two_particles();
simulate_single_particle_with_different_steps(); simulate_single_particle_with_different_steps();
// simulate_100_particles(); double t1 = omp_get_wtime();
// simulate_100_particles_with_time_potential(); simulate_100_particles();
//simulate_100_particles_with_time_potential();
double end = omp_get_wtime(); double end = omp_get_wtime();
std::cout << "Time: " << (end - start) << " seconds" << std::endl; std::cout << "Time: " << (end - t1) << " seconds" << std::endl;
return 0; return 0;
} }