Update board.hpp, forces.hpp, forces.cpp, main.cpp, pedestrian.hpp: correct some bugs in implementation

This commit is contained in:
AKallala
2026-04-23 20:14:24 +02:00
parent d347534ff2
commit aa1daf9149
5 changed files with 102 additions and 206 deletions
+35 -3
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@@ -1,9 +1,41 @@
#pragma once
#include "vector2d.hpp"
struct Obstacle {
Vector2d start;
Vector2d end;
Obstacle() : start(0, 0), end(0, 0) {}
Obstacle(Vector2d s, Vector2d e) : start(s), end(e) {}
// find the point of the obstacle that is nearest to p
Vector2d find_nearest_obstacle_point(Vector2d p) {
Vector2d obstacle_v = end - start;
double projection = (p - start).dot(obstacle_v) / obstacle_v.dot(obstacle_v);
if (projection < 0.0)
projection = 0.0;
if (projection > 1.0)
projection = 1.0;
return start + obstacle_v * projection;
}
};
struct Board {
double length, width;
Vector2d *borders; // array containing the position of each obstacle
int n_borders; // number of obstacles
Board(double l, double w, int n, Vector2d *border) : length(l), width(w), n_borders(n), borders(border) {}
Obstacle *obstacles; // array of obstacles (represented as lines) that are present on the board
int n_obstacles; // number of obstacles
Board(double l, double w, int n, Obstacle *o) : length(l), width(w), n_obstacles(n + 4) {
obstacles = new Obstacle[n + 4];
for (int i = 0; i < n; i++) {
obstacles[i] = o[i];
}
// borders of the board: bottom, right, top, left
obstacles[n] = Obstacle(Vector2d(0, 0), Vector2d(l, 0));
obstacles[n + 1] = Obstacle(Vector2d(l, 0), Vector2d(l, w));
obstacles[n + 2] = Obstacle(Vector2d(l, w), Vector2d(0, w));
obstacles[n + 3] = Obstacle(Vector2d(0, w), Vector2d(0, 0));
}
~Board() { delete[] obstacles; }
};
+25 -71
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@@ -1,35 +1,26 @@
#include "forces.hpp"
#include <math.h>
// # Done
double w(Vector2d e, Vector2d f) {
if (e.dot(f) >= f.norm() * cos_phi)
return 1.0;
return c;
else
return c;
}
double g(double v_max_alpha, double w_alpha_norm) {
if (w_alpha_norm <= v_max_alpha) {
return 1;
}
return v_max_alpha / w_alpha_norm;
}
// # Done
//
// $\vec{F}_\alpha(\vec{v}_\alpha, v^0_\alpha \vec{e}_\alpha) \vec{e}_\alpha(t) = \frac{1}{\tau_\alpha}(v^0_\alpha \vec{e}_\alpha - \vec{v}_\alpha)$
//
void compute_acceleration_term(Pedestrian *p) {
// $v_{\alpha}^{0}\vec{e}_{\alpha}$
Vector2d desired_velocity = p->e * p->desired_v0;
// $\vec{v}_{\alpha}(t)$
Vector2d actual_velocity = p->curr_vel;
double tau_alpha_inv = 1 / tau_alpha;
p->F_i += (desired_velocity - actual_velocity) * tau_alpha_inv;
p->f_i += (desired_velocity - actual_velocity) / tau_alpha;
}
// # Done
//
// $\sum_{\beta} \vec{F}_{\alpha\beta}(\vec{e}_{\alpha}, \vec{r}_{\alpha} - \vec{r}_{\beta})$
//
void compute_repulsive_effects_from_pedestrians(Pedestrian *pedestrians, Pedestrian *p, int N) {
for (int i = 0; i < N; i++) {
@@ -43,78 +34,41 @@ void compute_repulsive_effects_from_pedestrians(Pedestrian *pedestrians, Pedestr
// continue;
// }
// $\vec{r}_{\alpha\beta}$
Vector2d r_ab = p->curr_pos - pedestrians[i].curr_pos;
// $\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert$
double r_ab_norm = r_ab.norm();
// $\vec{e}_{\beta}$
Vector2d e_beta = pedestrians[i].e;
Vector2d e_b = pedestrians[i].e;
// $v_\beta \Delta t$
double v_beta_delta_t = pedestrians[i].desired_v0 * delta_t;
double s_b = pedestrians[i].desired_v0 * delta_t;
// $\vec{r}_{\alpha\beta} - \vec{v}_{\beta}\varDelta_{t}\vec{e}_{\beta}$
Vector2d r_ab_minus_v_beta_delta_t_e_beta = r_ab - (e_beta * v_beta_delta_t);
Vector2d r_ab2 = r_ab - (e_b * s_b);
// $\Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert$
double r_ab_minus_v_beta_delta_t_e_beta_norm = r_ab_minus_v_beta_delta_t_e_beta.norm();
double r_ab2_norm = r_ab2.norm();
// (4):
//
// $2b = \sqrt{(\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert)^2 - (v_\beta \Delta t)^2}$
//
double b = sqrt(pow(r_ab_norm + r_ab2_norm, 2) - pow(s_b, 2)) / 2;
double b = sqrt((r_ab_norm + r_ab_minus_v_beta_delta_t_e_beta_norm) * (r_ab_norm + r_ab_minus_v_beta_delta_t_e_beta_norm) - (v_beta_delta_t) * (v_beta_delta_t)) / 2;
Vector2d b_grad = (r_ab / r_ab_norm + r_ab2 / r_ab2_norm) * (r_ab_norm + r_ab2_norm) / (4 * b);
// (7):
//
// $\grad_{\vec{r}_{\alpha \beta}}b = \frac{(\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert) (\frac{\vec{r}_{\alpha \beta}}{\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert} + \frac{\vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta}{\Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert})}{4b}$
//
//
Vector2d delta_r_alpha_beta_b = (((r_ab / r_ab_norm) + (r_ab_minus_v_beta_delta_t_e_beta / r_ab_minus_v_beta_delta_t_e_beta_norm)) * (r_ab_norm + r_ab_minus_v_beta_delta_t_e_beta_norm)) / (4 * b);
Vector2d f_ped = b_grad * ((V0_AB / SIGMA) * (exp(-b / SIGMA)));
// (5):
//
// $\vec{f}_{\alpha \beta}(\vec{r}_{\alpha \beta}) = \frac{V^0_{\alpha \beta}}{\sigma}e^{-b / \sigma} \grad_{\vec{r}_{\alpha \beta}}b$
//
//
Vector2d f_alpha_beta_r_alpha_beta = delta_r_alpha_beta_b * ((V0_AB / SIGMA) * (exp(-b / SIGMA)));
// (11):
//
// $\vec{F}_{\alpha\beta}(\vec{e}_{\alpha}, \vec{r}_{\alpha} - \vec{r}_{\beta}) = w(\vec{e}_{\alpha}, -\vec{f}_{\alpha\beta})\vec{f}_{\alpha\beta}(\vec{r}_{\alpha} - \vec{r}_{\beta})$
//
// Add repulsive effects from other pedestrians to current pedestrian's social force
p->F_i += f_alpha_beta_r_alpha_beta * w(p->e, f_alpha_beta_r_alpha_beta * -1);
p->f_i += f_ped * w(p->e, f_ped * -1);
}
}
// # Done
void compute_repulsive_effects_from_borders(Board &B, Pedestrian *p) {
void compute_repulsive_effects_from_borders(Board &board, Pedestrian *p) {
Vector2d *borders = B.borders;
int n_borders = B.n_borders;
Obstacle *obstacles = board.obstacles;
int n_borders = board.n_obstacles;
for (int i = 0; i < n_borders; i++) {
Vector2d border = borders[i];
Obstacle obstacle = obstacles[i];
// $\vec{r}_{\alpha B}$
Vector2d r_alpha_B = p->curr_pos - border;
Vector2d r_aB = p->curr_pos - obstacle.find_nearest_obstacle_point(p->curr_pos);
//
// $\vec{F}_{\alpha B}(\vec{r}_{\alpha B}) = \frac{U^0_{\alpha B}}{R} e^{- \Arrowvert \vec{r}_{\alpha B} \Arrowvert / R} \frac{\vec{r}_{\alpha B}}{\Arrowvert \vec{r}_{\alpha B} \Arrowvert}$
//
Vector2d f_obst = (r_aB / r_aB.norm()) * (U0_AB / R) * std::exp(-r_aB.norm() / R);
Vector2d F_alpha_B = (r_alpha_B / r_alpha_B.norm()) * (U0_AB / R) * std::exp(-r_alpha_B.norm() / R);
// (12):
//
// $\vec{F}_{\alpha B}(\vec{e}_{\alpha}, \vec{r}_{\alpha} - \vec{r}_{ B}) = w(\vec{e}_{\alpha}, -\vec{F}_{\alpha B})\vec{F}_{\alpha B}(\vec{r}_{\alpha} - \vec{r}_{ B})$
//
p->F_i += F_alpha_B * w(p->e, F_alpha_B * (-1));
p->f_i += f_obst;
}
}
+5 -18
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@@ -3,46 +3,33 @@
#include "pedestrian.hpp"
#include <cmath>
// $\tau_{\alpha}$
// https://arxiv.org/pdf/cond-mat/9805244, page 8
const double tau_alpha = 0.5;
// $V^0_{\alpha \beta}$
// https://arxiv.org/pdf/cond-mat/9805244, page 8
const double V0_AB = 2.1;
// $\sigma$
// https://arxiv.org/pdf/cond-mat/9805244, page 8
const double SIGMA = 0.3;
// $U^0_{\alpha B}$
// https://arxiv.org/pdf/cond-mat/9805244, page 8
const double U0_AB = 10.0;
// $R$
// https://arxiv.org/pdf/cond-mat/9805244, page 8
const double R = 0.2;
// $c$
// https://arxiv.org/pdf/cond-mat/9805244, page 8
const double c = 0.5;
// $\varphi$
// https://arxiv.org/pdf/cond-mat/9805244, page 8
const double phi = 100.0;
const double phi = 100.0 / 180.0 * M_PI;
const double cos_phi = cos(phi);
// $\varDelta_{t}$
// step size = 0.2 seconds
// https://arxiv.org/pdf/cond-mat/9805244, page 8
const double delta_t = 2;
const double dt = 0.01;
// # Optional (forces.cpp: compute_repulsive_effects_from_pedestrians)
// const double DISTANCE = 2.0;
double w(Vector2d e, Vector2d f);
double g(double v_max_alpha, double w_alpha_norm);
void compute_acceleration_term(Pedestrian *p);
void compute_repulsive_effects_from_pedestrians(Pedestrian *P, Pedestrian *p, int N);
+30 -43
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@@ -4,12 +4,8 @@
#include "pedestrian.hpp"
#include "vector2d.hpp"
double g(double v_max_alpha, double w_alpha_norm) {
if (w_alpha_norm <= v_max_alpha) {
return 1;
}
return v_max_alpha / w_alpha_norm;
}
#define BOARD_WIDTH 10.0
#define BOARD_LENGTH 50.0
using namespace std;
@@ -23,67 +19,58 @@ using namespace std;
Pedestrian *init_pedestrians(int n_p) {
Pedestrian *P = new Pedestrian[n_p];
for (int i = 0; i < n_p; i++) {
P[i] = Pedestrian();
std::random_device rd; // use for truly random simulation
std::mt19937 gen(rd()); // use rd instead of 42 as seed for real randomness
std::normal_distribution<double> velocity_gen(1.34, 0.26); // 1.34 and 0.26 are the mean and stdrd deviation used in paper
std::uniform_real_distribution<double> x_gen(2, BOARD_LENGTH - 2);
std::uniform_real_distribution<double> y_gen(2, BOARD_WIDTH - 2);
for (int i = 0; i < n_p / 2; i++) {
Vector2d start_pos = Vector2d(1, y_gen(gen));
Vector2d destination = Vector2d(BOARD_LENGTH - 1, y_gen(gen));
double desired_v0 = velocity_gen(gen);
double v_max = 1.3 * desired_v0;
P[i] = Pedestrian(WHITE, (destination - start_pos) / (destination - start_pos).norm() * desired_v0, start_pos, (destination - start_pos) / (destination - start_pos).norm(), v_max, desired_v0, destination, Vector2d());
}
for (int i = n_p / 2; i < n_p; i++) {
Vector2d start_pos = Vector2d(BOARD_LENGTH - 1, y_gen(gen));
Vector2d destination = Vector2d(1, y_gen(gen));
double desired_v0 = velocity_gen(gen);
double v_max = 1.3 * desired_v0;
P[i] = Pedestrian(BLACK, (destination - start_pos) / (destination - start_pos).norm() * desired_v0, start_pos, (destination - start_pos) / (destination - start_pos).norm(), v_max, desired_v0, destination, Vector2d(0, 0));
}
return P;
}
Board init_board(int width, int length) {
Vector2d obs[] = {Vector2d(2.0, 1.0), Vector2d(4.0, 1.0), Vector2d(6.0, 2.0), Vector2d(6.0, 4.0)};
return Board(width, length, 4, obs);
}
int main(int argc, const char *argv[]) {
int main(int argc, const char* argv[]) {
Board B = init_board(10, 15);
Obstacle obs[] = {};
Board board = Board(BOARD_LENGTH, BOARD_WIDTH, 0, obs);
int n_p = atoi(argv[1]);
int n_iter = atoi(argv[2]);
Pedestrian *pedestrians = init_pedestrians(n_p);
for (int t = 0; t < n_iter; t++) {
for (int i = 0; i < n_p; i++) {
Pedestrian &p = pedestrians[i];
p.F_i.reset();
p.f_i.reset();
//
// $\vec{F}_\alpha(\vec{v}_\alpha, v^0_\alpha \vec{e}_\alpha) \vec{e}_\alpha(t) = \frac{1}{\tau_\alpha}(v^0_\alpha \vec{e}_\alpha - \vec{v}_\alpha)$
//
compute_acceleration_term(&p);
//
// $\sum_{\beta} \vec{F}_{\alpha\beta}(\vec{e}_{\alpha}, \vec{r}_{\alpha} - \vec{r}_{\beta})$
//
compute_repulsive_effects_from_pedestrians(pedestrians, &p, n_p);
//
// $\sum_{B} \vec{F}_{\alpha B}(\vec{e}_{\alpha}, \vec{r}_{\alpha} - \vec{r}_{B})$
//
compute_repulsive_effects_from_borders(B, &p);
compute_repulsive_effects_from_borders(board, &p);
//
// $\vec{w}_i = \vec{v}_i + \vec{F}_idt$
//
p.w_alpha = p.curr_vel + p.F_i * delta_t;
Vector2d w_alpha = p.curr_vel + p.f_i * dt;
//
// $\vec{v}_i^{t+1} = \vec{w}_ig(\frac{v^{max}_i}{\Arrowvert \vec{w}_i \Arrowvert}) $
//
p.next_vel = p.w_alpha * g(p.v_max, p.w_alpha.norm());
p.curr_vel = w_alpha * g(p.v_max, w_alpha.norm());
//
// $\vec{r}_i^{t+1} += \vec{r}^t_i + v^t_idt$
//
p.curr_pos = p.curr_pos + p.curr_vel * delta_t;
}
p.curr_pos = p.curr_pos + p.curr_vel * dt;
for (int i = 0; i < n_p; i++) {
pedestrians[i].update();
p.e = (p.destination - p.curr_pos) / (p.destination - p.curr_pos).norm();
}
}
+7 -71
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@@ -1,85 +1,21 @@
#pragma once
#include "vector2d.hpp"
#include "random"
#include "vector2d.hpp"
// For visual simulation
enum Color { BLACK, WHITE };
struct Pedestrian {
// TODO: Update initial values
Pedestrian() :
curr_vel(),
curr_pos(),
e(),
v_max(1.34 * 1.3),
desired_v0(1.34),
destination(),
F_i(),
next_pos(),
next_vel(),
w_alpha()
{}
Pedestrian(
Vector2d c_v,
Vector2d c_p,
Vector2d e,
Vector2d d,
Vector2d f,
Vector2d n_p,
Vector2d n_v,
Vector2d w_alpha
) :
curr_vel(c_v),
curr_pos(c_p),
e(e),
v_max(),
desired_v0(),
destination(d),
F_i(f),
next_pos(n_p),
next_vel(n_v),
w_alpha(w_alpha)
{}
// $\vec{v}_{\alpha}(t)$
Color color;
Vector2d curr_vel;
// $\vec{r}_\alpha(t)$
Vector2d curr_pos;
// $\vec{e}_{\alpha}(t)$
Vector2d e;
// $v_{\alpha}^{max} = 1.3 v^{0}_{\alpha}$
double v_max;
// $v_\alpha^0$
double desired_v0;
// # =============================================================
// $\vec{r}^0_\alpha$
Vector2d destination;
Vector2d f_i;
// social force
Vector2d F_i;
Pedestrian() : color(WHITE), curr_vel(0.0, 0.0), curr_pos(0.0, 0.0), e(0.0, 0.0), v_max(0.0), desired_v0(0.0), destination(0.0, 0.0), f_i(0.0, 0.0) {}
// # =============================================================
// $\vec{r}_\alpha(t+1)$
Vector2d next_pos;
// $\vec{v}_{\alpha}(t + 1)$
Vector2d next_vel;
// $\vec{w}_{\alpha}$
Vector2d w_alpha;
// # =============================================================
void update() {
curr_pos = next_pos;
curr_vel = next_vel;
e = (destination - curr_pos) / (destination - curr_pos).norm();
}
Pedestrian(Color clr, Vector2d c_v, Vector2d c_p, Vector2d e, double v_max, double desired_v0, Vector2d d, Vector2d f) : color(clr), curr_vel(c_v), curr_pos(c_p), e(e), v_max(v_max), desired_v0(desired_v0), destination(d), f_i(f) {}
};