Flop Count Calculations + x86 Measurements + c13 Fix

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[Quy Anh] «Elliot» Nguyen
2026-06-17 07:28:11 +02:00
parent 42b3c7097e
commit a7d45665da
225 changed files with 19699 additions and 172 deletions
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// This file is merged from the forces.cpp and social_forces_baseline.cpp
// The goal is that we from now on only have one file as our baseline
// This should make it more easy in the future to implement optimizations
// Our naming convention from now on is: variant_<variant_name>.cpp (Please make sure to keep that consistent, otherwise our Makefile wont work anymore)
#include "../headers/board.hpp"
#include "../headers/constants.hpp"
#include "../headers/pedestrian.hpp"
#include "../headers/vector2d.hpp"
#include <algorithm>
#include <cmath>
#include <fstream>
#include <iostream>
#include <math.h> // keep — forces code uses unqualified sqrt/exp
#include <random>
#include <tuple>
#include <vector>
#define SEED 42
#define BOARD_WIDTH 10.0
#define BOARD_LENGTH 50.0
#define WALL_EPS 1e-3
#define BOARD_WIDTH_MINUS_WALL_EPS 9.999
#ifndef RANDOM_SEED
#define RANDOM_SEED 0
#endif
#ifndef BENCHMARK
#define BENCHMARK 0
#endif
using namespace std;
// forces.cpp
// Flop count: 2 ADDs, 6 MULTs
double w_ped(Vector2d e, Vector2d f) {
double f_norm_sq = f.dot(f);
double rhs = f_norm_sq * cos_phi_sq;
double e_dot_f = e.dot(f);
double e_dot_f_sq = e_dot_f * e_dot_f;
if (e_dot_f >= 0.0 || e_dot_f_sq <= rhs)
return dt_neg;
else
return c_neg_times_dt;
}
double w_obstacle(Vector2d e, Vector2d f) {
double e_dot_f = (f.y == 0) ? 0 : (f.y < 0 ? -e.y : e.y);
if (e_dot_f >= cos_phi)
return dt_neg;
else
return c_neg_times_dt;
}
// Flop count: 2 ADDs, 4 MULTs
Vector2d acceleration_term_dt(const Pedestrian &alpha) {
// # 2 MULTs
Vector2d desired_velocity = alpha.e * alpha.desired_v0;
Vector2d actual_velocity = alpha.curr_vel;
// # 2 ADDs, 2 MULTs
Vector2d f_alpha_0_dt = (desired_velocity - actual_velocity) * dt_times_tau_alpha_inv;
return f_alpha_0_dt;
}
// Flop count: 12 ADDs, 24 MULTs, 1 DIV, 3 SQRTs, 1 EXP
Vector2d pedestrian_repulsion_dt(const Pedestrian &alpha, const Pedestrian &beta) {
// # 2 ADDs
// $\vec{r}_{\alpha\beta}$
Vector2d r_ab = alpha.curr_pos - beta.curr_pos;
// # 1 ADD, 2 MULTs, 1 SQRT
// $\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert$
double r_ab_norm = r_ab.norm();
r_ab_norm = r_ab_norm > EPS ? r_ab_norm : EPS; // Avoid division by zero
// $v_\beta \Delta t \vec{e}_\beta$
Vector2d s_b_e = beta.s_b_e;
// # 2 ADDs
// $\vec{r}_{\alpha\beta} - \vec{v}_{\beta}\varDelta_{t}\vec{e}_{\beta}$
Vector2d r_ab2 = r_ab - s_b_e;
// # 1 ADD, 2 MULTs, 1 SQRT
// $\Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert$
double r_ab2_norm = r_ab2.norm();
r_ab2_norm = r_ab2_norm > EPS ? r_ab2_norm : EPS; // Avoid division by zero
// # 1 ADD
// $\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert$
double r_ab_norm_sum = r_ab_norm + r_ab2_norm;
// # 1 ADD, 1 MULTs, 1 SQRT
//
// $2b = \sqrt{(\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert)^2 - (v_\beta \Delta t)^2}$
//
double two_b_sq = r_ab_norm_sum * r_ab_norm_sum - beta.s_b_sq;
two_b_sq = two_b_sq > EPS_SQ ? two_b_sq : EPS_SQ; // Avoid sqrt of negative and avoid division by zero
double two_b = sqrt(two_b_sq);
// # 5 MULTs, 1 DIV, 1 EXP
//
// $\frac{-V^0_{\alpha\beta}}{2\sigma}\,e^{-b/\sigma}\,\frac{\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert}{2b\,\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert\,\Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert}$
//
double scalar_mult_common = (r_ab_norm_sum / (two_b * r_ab_norm * r_ab2_norm)) * (NEG_V0_AB_div_TWO_SIGMA * exp(two_b * NEG_TWO_SIGMA_INV));
// # 1 MULT
//
// $\frac{-V^0_{\alpha\beta}}{2\sigma}\,e^{-b/\sigma}\,\frac{\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert}{2b\,\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert}$
//
double scalar_mult_r_ab = scalar_mult_common * r_ab2_norm;
// # 1 MULT
//
// $\frac{-V^0_{\alpha\beta}}{2\sigma}\,e^{-b/\sigma}\,\frac{\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert}{2b\,\Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert}$
//
double scalar_mult_r_ab2 = scalar_mult_common * r_ab_norm;
// # 2 ADDs, 4 MULTs
//
// $\vec{-f}_{\alpha \beta}(\vec{r}_{\alpha \beta}) = \frac{-V^0_{\alpha \beta}}{2\sigma}e^{-b / \sigma} 2\grad_{\vec{r}_{\alpha \beta}}b $
//
//
// $= \frac{-V^0_{\alpha\beta}}{2\sigma}\,e^{-b/\sigma}\,\frac{\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert}{2b\,\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert}\,\vec{r}_{\alpha \beta} + \frac{-V^0_{\alpha\beta}}{2\sigma}\,e^{-b/\sigma}\,\frac{\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert}{2b\,\Arrowvert \vec{r}_{\alpha \beta} -
// v_\beta \Delta t \vec{e}_\beta \Arrowvert}\,(\vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta)$
//
//
//
// $2\grad_{\vec{r}_{\alpha \beta}}b = \frac{(\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert)(\frac{\vec{r}_{\alpha \beta}}{\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert} + \frac{\vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta}{\Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert})}{2b}$
//
//
// $= \frac{\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta Delta t \vec{e}_\beta \Arrowvert}{2b\,\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert}\,\vec{r}_{\alpha \beta} + \frac{\Arrowvert \vec{r}_{\alpha \beta} \Arrowvert + \Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert}{2b\,\Arrowvert \vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta \Arrowvert}\,(\vec{r}_{\alpha \beta} - v_\beta \Delta t \vec{e}_\beta)$
//
//
Vector2d f_alpha_beta_neg = r_ab * scalar_mult_r_ab + r_ab2 * scalar_mult_r_ab2;
// # 2 ADDs, 8 MULTs
//
// $\vec{F}_{\alpha\beta}(\vec{e}_{\alpha}, \vec{r}_{\alpha \beta}).dt = w(\vec{e}_{\alpha}, -\vec{f}_{\alpha\beta}(\vec{r}_{\alpha \beta})).\vec{f}_{\alpha\beta}(\vec{r}_{\alpha \beta}).dt$
//
Vector2d f_alpha_beta_dt = f_alpha_beta_neg * w_ped(alpha.e, f_alpha_beta_neg);
return f_alpha_beta_dt;
}
// Flop count: 8 ADDs, 13 MULTs, 1 DIV, 1 SQRT, 1 EXP
Vector2d obstacle_repulsion_dt(const Pedestrian &alpha, const Obstacle &B) {
// # 7 ADDs, 5 MULTs
// $\vec{r}_{\alpha B}$
Vector2d r_aB = alpha.curr_pos - B.find_nearest_obstacle_point(alpha.curr_pos);
// # 1 ADD, 2 MULTs, 1 SQRT
// $\Arrowvert \vec{r}_{\alpha B} \Arrowvert$
double r_aB_norm = r_aB.norm();
r_aB_norm = r_aB_norm > EPS ? r_aB_norm : EPS; // Avoid division by zero
// # 2 MULTs, 1 DIV, 1 EXP
//
// $\frac{-U^0_{\alpha B}}{R} e^{- \Arrowvert \vec{r}_{\alpha B} \Arrowvert / R}$
//
double scalar_mult = (NEG_U0_AB_div_R * exp(r_aB_norm * NEG_R_INV)) / r_aB_norm;
// # 2 MULTs
//
// $-\vec{F}_{\alpha B}(\vec{r}_{\alpha B}) = \frac{-U^0_{\alpha B}}{R} e^{- \Arrowvert \vec{r}_{\alpha B} \Arrowvert / R} \frac{\vec{r}_{\alpha B}}{\Arrowvert \vec{r}_{\alpha B} \Arrowvert}$
//
Vector2d f_alpha_B_neg = r_aB * scalar_mult;
// # 2 MULTs
//
// $\vec{F}_{\alpha B}(\vec{e}_{\alpha}, \vec{r}_{\alpha B}).dt = w(\vec{e}_{\alpha}, -\vec{F}_{\alpha B}(\vec{r}_{\alpha B})).\vec{F}_{\alpha B}(\vec{r}_{\alpha B}).dt$
//
Vector2d f_alpha_B_dt = f_alpha_B_neg * w_obstacle(alpha.e, f_alpha_B_neg);
return f_alpha_B_dt;
}
// social_force_baseline.cpp
Pedestrian *init_pedestrians(int n_p) {
#if RANDOM_SEED
random_device rd; // Platform-provided random seed source.
mt19937 gen(rd()); // Non-reproducible initialization.
#else
mt19937 gen(SEED); // Reproducible initialization.
#endif
normal_distribution<double> velocity_gen(v0_mean, v0_std_dev);
uniform_real_distribution<double> y_gen(0.3, BOARD_WIDTH - 0.3);
uniform_real_distribution<double> x_gen_left(2.0, BOARD_LENGTH / 2.0);
uniform_real_distribution<double> x_gen_right(BOARD_LENGTH / 2.0, BOARD_LENGTH - 2.0);
Pedestrian *P = new Pedestrian[n_p];
int n_p_half = n_p / 2;
// Group of pedestrians walking from left to right.
for (int i = 0; i < n_p_half; i++) {
double x = x_gen_left(gen);
double y = y_gen(gen);
Vector2d start_pos = Vector2d(x, y);
Vector2d destination = Vector2d(BOARD_LENGTH + 30.0, y);
Vector2d init_e = destination - start_pos;
double init_e_norm = init_e.norm();
Vector2d init_e_unit = init_e / init_e_norm;
// Reject near-zero desired speeds to avoid pedestrians that barely move,
// and reject negative speeds because they would reverse the intended
// walking direction.
double desired_v0;
do {
desired_v0 = velocity_gen(gen);
} while (desired_v0 <= 0.1);
double v_max = 1.3 * desired_v0;
P[i] = Pedestrian(WHITE, Vector2d(), start_pos, init_e_unit, v_max, desired_v0, destination);
}
// Group of pedestrians walking from right to left.
for (int i = n_p_half; i < n_p; i++) {
double x = x_gen_right(gen);
double y = y_gen(gen);
Vector2d start_pos = Vector2d(x, y);
Vector2d destination = Vector2d(-30.0, y);
Vector2d init_e = destination - start_pos;
double init_e_norm = init_e.norm();
Vector2d init_e_unit = init_e / init_e_norm;
// Reject near-zero desired speeds to avoid pedestrians that barely move,
// and reject negative speeds because they would reverse the intended
// walking direction.
double desired_v0;
do {
desired_v0 = velocity_gen(gen);
} while (desired_v0 <= 0.1);
double v_max = 1.3 * desired_v0;
P[i] = Pedestrian(BLACK, Vector2d(), start_pos, init_e_unit, v_max, desired_v0, destination);
}
return P;
}
Board init_board_without_obstacles() { return Board(BOARD_LENGTH, BOARD_WIDTH, 0, nullptr); }
int run_simulation(Pedestrian *pedestrians, Board &board, int n_p, int n_iter, const char *dump_path) {
#if BENCHMARK
// Avoid compiler unused parameter warning
(void)dump_path;
#endif
#if !BENCHMARK
const int dump_interval = 1;
// Each sample stores: time step, pedestrian id, x, y, e.x, e.y, color.
vector<tuple<int, int, double, double, double, double, int>> samples;
if (dump_path) {
samples.reserve(static_cast<size_t>(n_iter / dump_interval + 1) * n_p);
// Store the initial state before the first simulation step.
for (int i = 0; i < n_p; i++) {
Pedestrian &p = pedestrians[i];
samples.emplace_back(0, i, p.curr_pos.x, p.curr_pos.y, p.e.x, p.e.y, p.color);
}
}
#endif
// # ADDs: n_iter * (
// # n_p * 4 +
// # n_p * (n_p - 1) * 14 +
// # n_p * board.n_obstacles * 10 +
// # n_p * 7
// # )
// # MULTs: n_iter * (
// # n_p * 4
// # n_p * (n_p - 1) * 24 +
// # n_p * board.n_obstacles * 13 +
// # n_p * 16
// # )
// # DIVs: n_iter * (
// # n_p * (n_p - 1) +
// # n_p * board.n_obstacles +
// # n_p * 2
// # )
// # SQRTs: n_iter * (
// # n_p * (n_p - 1) * 3 +
// # n_p * board.n_obstacles +
// # n_p * 3
// # )
// # EXPs: n_iter * (
// # n_p * (n_p - 1) +
// # n_p * board.n_obstacles
// # )
for (int t = 0; t < n_iter; t++) {
// Pass 1: Compute all forces from the current state.
for (int i = 0; i < n_p; i++) {
Pedestrian &p = pedestrians[i];
// # 2 ADDs, 4 MULTs
//
// $\vec{F}_\alpha(\vec{v}_\alpha, v^0_\alpha \vec{e}_\alpha) = \frac{1}{\tau_\alpha}(v^0_\alpha \vec{e}_\alpha - \vec{v}_\alpha)$
//
Vector2d f_alpha_dt = acceleration_term_dt(p);
// # (N-1) * (14 ADDs, 24 MULTs, 1 DIV, 3 SQRTs, 1 EXP)
//
// $\sum_{\beta} \vec{F}_{\alpha\beta}(\vec{e}_{\alpha},\vec{r}_{\alpha} - \vec{r}_{\beta})$
//
for (int j = 0; j < n_p; j++) {
if (i == j)
continue;
f_alpha_dt += pedestrian_repulsion_dt(p, pedestrians[j]);
}
// # board.n_obstacles * (10 ADDs, 13 MULTs, 1 DIV, 1 SQRT, 1 EXP)
//
// $\sum_{B} \vec{F}_{\alpha B}(\vec{e}_{\alpha}, \vec{r}_{\alpha} - \vec{r}_{B})$
//
for (int k = 0; k < board.n_obstacles; k++) {
f_alpha_dt += obstacle_repulsion_dt(p, board.obstacles[k]);
}
// # 2 ADDs
//
//
// $\frac{d\vec{w}_\alpha}{dt} = \vec{F}_{\alpha}(t)$
//
p.w += f_alpha_dt;
}
// Pass 2: Update pedestrian states after all forces have been computed.
// # (7 ADDs, 16 MULTs, 2 DIVs, 3 SQRTs) * n_p
for (int i = 0; i < n_p; i++) {
Pedestrian &p = pedestrians[i];
// # 1 ADD, 2 MULTs, 1 SQRT
double w_norm = p.w.norm();
double w_norm2 = w_norm > EPS ? w_norm : EPS; // Avoid division by zero.
// # 1 DIV
double correction_factor = std::min(1.0, p.v_max / w_norm2);
// # 2 MULTs
p.curr_vel = p.w * correction_factor;
// # 2 ADDs, 2 MULTs
//
// $\vec{r}_i^{t+1} = \vec{r}_i^t + \vec{v}_i^t dt$
//
p.curr_pos = p.curr_pos + p.curr_vel * dt;
// When a pedestrian reaches the end of the corridor, teleport them back
// to the opposite entrance while keeping the same y-coordinate. This
// maintains a constant pedestrian flow and makes lane formation easier to
// observe.
if (p.color == WHITE && p.curr_pos.x > (BOARD_LENGTH - 1.5)) {
p.curr_pos.x = 1.0;
p.destination.y = p.curr_pos.y;
p.w = Vector2d(p.desired_v0, 0.0);
p.curr_vel = p.w;
}
if (p.color == BLACK && p.curr_pos.x < 1.5) {
p.curr_pos.x = BOARD_LENGTH - 1.0;
p.destination.y = p.curr_pos.y;
p.w = Vector2d(-p.desired_v0, 0.0);
p.curr_vel = p.w;
}
// Keep pedestrians inside the board boundaries.
p.curr_pos.y = clamp(p.curr_pos.y, WALL_EPS, BOARD_WIDTH_MINUS_WALL_EPS);
// # 2 ADDs
Vector2d e = p.destination - p.curr_pos;
// # 1 ADD, 2 MULTs, 1 DIV, 1 SQRT
double e_norm = e.norm();
double e_norm2 = e_norm > EPS ? e_norm : EPS; // Avoid division by zero.
double e_norm_inv = 1.0 / e_norm2;
// # 2 MULTs
p.e = e * e_norm_inv;
// # 1 ADD, 2 MULTs
double velocity_norm_sq = p.curr_vel.dot(p.curr_vel);
// # 1 SQRT
double velocity_norm = std::sqrt(velocity_norm_sq);
// # 1 MULT
p.s_b_sq = velocity_norm_sq * delta_t_sq;
// # 3 MULTs
p.s_b_e = p.e * (velocity_norm * delta_t);
#if !BENCHMARK
// Store the current pedestrian state for visualization.
if (dump_path && (t % dump_interval == 0)) {
samples.emplace_back(t + 1, i, p.curr_pos.x, p.curr_pos.y, p.e.x, p.e.y, p.color);
}
#endif
}
}
#if !BENCHMARK
// Export recorded simulation states to CSV.
if (dump_path) {
ofstream out(dump_path);
out << "time,id,x,y,p.e.x,p.e.y,color\n";
for (auto &[t, id, x, y, e_x, e_y, c] : samples) {
out << t << ',' << id << ',' << x << ',' << y << ',' << e_x << ',' << e_y << ',' << c << '\n';
}
}
#endif
return 0;
}