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Some changes - not sure exactly what

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This commit is contained in:
Thomas Faour 2025-06-02 23:08:35 -04:00
parent b10bc5b5da
commit 460d984b3b
7 changed files with 122 additions and 87 deletions
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36
animate.py
View File

@ -50,19 +50,45 @@ def read_output_file(filename):
name = data['name']
pos = data['position']
# Store position
positions[name].append((pos[0], pos[1]))
frame += 1
times.append(frame)
return positions, times
def create_animation(positions, times, output_file=None):
def center_positions(positions, center_body):
"""Center all positions relative to the specified body."""
if center_body not in positions:
print(f"Warning: Center body '{center_body}' not found in simulation")
return positions
centered_positions = defaultdict(list)
for frame in range(len(next(iter(positions.values())))):
# Get center body position for this frame
center_pos = positions[center_body][frame]
# Shift all positions relative to center body
for name, pos_list in positions.items():
if frame < len(pos_list):
pos = pos_list[frame]
centered_pos = (pos[0] - center_pos[0], pos[1] - center_pos[1])
centered_positions[name].append(centered_pos)
return centered_positions
def create_animation(positions, times, output_file=None, center_body=None):
"""Create an animation of the bodies' orbits."""
# Check if we have any data
if not positions or not times:
print("Error: No valid data found in the input file")
return
# Center positions if requested
if center_body:
positions = center_positions(positions, center_body)
# Set up the figure and axis
fig, ax = plt.subplots(figsize=(10, 10))
@ -77,7 +103,10 @@ def create_animation(positions, times, output_file=None):
# Set up the plot
ax.set_xlabel('X (m)')
ax.set_ylabel('Y (m)')
ax.set_title('Orbital Simulation')
title = 'Orbital Simulation'
if center_body:
title += f' (centered on {center_body})'
ax.set_title(title)
ax.legend()
# Find the bounds of the plot
@ -126,10 +155,11 @@ def main():
parser = argparse.ArgumentParser(description='Animate orbital simulation output')
parser.add_argument('input_file', help='Input file from simulation')
parser.add_argument('--output', '-o', help='Output video file (optional)')
parser.add_argument('--center', '-c', help='Center the animation on this body')
args = parser.parse_args()
positions, times = read_output_file(args.input_file)
create_animation(positions, times, args.output)
create_animation(positions, times, args.output, args.center)
if __name__ == '__main__':
main()

4
config/planets.json
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@ -1,5 +1,5 @@
{
"planets": [
"bodies": [
{
"name": "Earth",
"mass": 5.972e24,
@ -10,7 +10,7 @@
"name": "Moon",
"mass": 7.34767309e22,
"position": [149982270700, 0, 0],
"velocity": [0, 30802, 0]
"velocity": [0, 30822, 0]
},
{
"name": "Sun",

11
src/body.cpp
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@ -3,7 +3,6 @@
#include <cmath>
#include <ranges>
Body::Body(const Position& X, const Velocity& V, const Mass& m, const std::string& name)
: X(X), V(V), m(m), name(name) {
A = Acceleration{Decimal(0), Decimal(0), Decimal(0)};
@ -15,6 +14,12 @@ void Body::addAcceleration(const Acceleration& new_A) {
}
}
void Body::subAcceleration(const Acceleration& new_A) {
for (const auto& [new_a, cur_a]: std::views::zip(new_A, this->A)){
cur_a -= new_a;
}
}
std::tuple<Position, Velocity, Mass> Body::save() const {
return std::make_tuple(X, V, m);
}
@ -66,8 +71,8 @@ std::string Body::speed() const {
std::string Body::toString() const {
std::string pos_str, vel_str;
for (int i = 0; i < 3; ++i) {
pos_str += format_sig_figs(real_pos(X[i]), 3) + "m ";
vel_str += format_sig_figs(real_vel(V[i]), 3) + "m/s ";
pos_str += format_sig_figs(real_pos(X[i]), 10) + "m ";
vel_str += format_sig_figs(real_vel(V[i]), 10) + "m/s ";
}
return name + ": X = " + pos_str + ", V = " + vel_str;
}

6
src/body.hpp
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@ -3,10 +3,12 @@
#include "units.hpp"
#include <string>
#include <tuple>
#include <memory>
class Body {
public:
Body(const Position& X, const Velocity& V, const Mass& m, const std::string& name = "");
Body(const Position& X, const Velocity& V, const Mass& m,
const std::string& name = "");
// Save and load state
std::tuple<Position, Velocity, Mass> save() const;
@ -31,7 +33,7 @@ public:
void setAcceleration(const Acceleration& new_A) { A = new_A; }
void addAcceleration(const Acceleration& new_A);
void subAcceleration(const Acceleration& new_A);
// String representation
std::string toString() const;

19
src/main.cpp
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@ -52,7 +52,7 @@ SimulationConfig parse_command_line(int argc, char* argv[]) {
desc.add_options()
("help,h", "Show help message")
("config,c", po::value<std::string>(&config.config_file)->required(),
"Path to planet configuration file (JSON)")
"Path to body configuration file (JSON)")
("output,o", po::value<std::string>(&config.output_file)->required(),
"Path to output file")
("time,t", po::value<std::string>()->required(),
@ -97,7 +97,7 @@ SimulationConfig parse_command_line(int argc, char* argv[]) {
return config;
}
std::vector<Body> load_planets(const std::string& config_file) {
std::vector<Body> load_bodies(const std::string& config_file) {
std::ifstream f(config_file);
if (!f.is_open()) {
throw std::runtime_error("Could not open config file: " + config_file);
@ -107,12 +107,12 @@ std::vector<Body> load_planets(const std::string& config_file) {
f >> j;
std::vector<Body> bodies;
for (const auto& planet : j["planets"]) {
std::string name = planet["name"];
double mass = planet["mass"];
for (const auto& body : j["bodies"]) {
std::string name = body["name"];
double mass = body["mass"];
std::vector<double> pos = planet["position"];
std::vector<double> vel = planet["velocity"];
std::vector<double> pos = body["position"];
std::vector<double> vel = body["velocity"];
if (pos.size() != 3 || vel.size() != 3) {
throw std::runtime_error("Position and velocity must be 3D vectors");
@ -124,6 +124,7 @@ std::vector<Body> load_planets(const std::string& config_file) {
Mass normalized_mass = norm_mass(mass);
bodies.emplace_back(position, velocity, normalized_mass, name);
std::cout << "Loaded " << name << " with mass " << mass << " kg\n";
}
@ -135,8 +136,8 @@ int main(int argc, char* argv[]) {
// Parse command line options
auto config = parse_command_line(argc, argv);
// Load planets from config file
auto bodies = load_planets(config.config_file);
// Load bodies from config file
auto bodies = load_bodies(config.config_file);
// Create and run simulator
Simulator simulator(

33
src/simulator.cpp
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@ -6,16 +6,16 @@
#include <stdexcept>
Simulator::Simulator(const std::vector<Body>& bodies,
Decimal step_size,
int steps_per_save,
const std::filesystem::path& output_file,
int current_step,
bool overwrite_output)
: bodies(bodies)
, step_size(step_size)
, steps_per_save(steps_per_save)
, output_file(output_file)
, current_step(current_step) {
Decimal step_size,
int steps_per_save,
const std::filesystem::path& output_file,
int current_step,
bool overwrite_output)
: bodies(bodies),
step_size(step_size),
steps_per_save(steps_per_save),
output_file(output_file),
current_step(current_step) {
if (std::filesystem::exists(output_file) && !overwrite_output) {
throw std::runtime_error("File " + output_file.string() + " exists and overwrite flag not given.");
@ -28,14 +28,14 @@ Simulator::Simulator(const std::vector<Body>& bodies,
clear.close();
}
// Write initial header with masses
out.open(output_file, std::ios::app);
if (!out) {
throw std::runtime_error("Failed to open output file: " + output_file.string());
}
for (const auto& body : bodies) {
out << body.getName() << ": " << body.getMass() << "\n";
out << body.getName() << ": mass=" << body.getMass();
out << "\n";
}
out << "\n";
@ -76,14 +76,13 @@ void Simulator::calculate_forces() {
body.setAcceleration(Acceleration{Decimal(0), Decimal(0), Decimal(0)});
}
for (size_t i = 0; i < bodies.size(); i++){
for (size_t i = 0; i < bodies.size(); i++) {
for (size_t j = i + 1; j < bodies.size(); j++) {
Position vec;
for (int k = 0; k < 3; ++k) {
vec[k] = bodies[i].getPosition()[k] - bodies[j].getPosition()[k];
vec[k] = positions[i][k] - positions[j][k];
}
// Calculate distance
Decimal dist = std::sqrt(vec[0] * vec[0] + vec[1] * vec[1] + vec[2] * vec[2]);
// Calculate force magnitude using Newton's law of gravitation
@ -91,7 +90,6 @@ void Simulator::calculate_forces() {
// for the acceleration. Use r^3 to avoid normalizing vec when multiplying later
Decimal force_magnitude = 1 / (dist * dist * dist);
// Calculate acceleration for both bodies
Decimal acc_magnitude_i = force_magnitude * bodies[j].getMass();
Decimal acc_magnitude_j = force_magnitude * bodies[i].getMass();
@ -102,11 +100,11 @@ void Simulator::calculate_forces() {
acc_j[k] = vec[k] * acc_magnitude_j;
}
// Add this component to the two bodies
bodies[i].addAcceleration(acc_i);
bodies[j].addAcceleration(acc_j);
}
}
}
void Simulator::move_bodies() {
@ -119,6 +117,5 @@ void Simulator::checkpoint() {
for (const auto& body : bodies) {
out << body.toString() << "\n";
}
out << "\n";
out.flush();
}

92
tests/simulator_test.cpp
View File

@ -1,54 +1,54 @@
#include <gtest/gtest.h>
#include "simulator.hpp"
#include <vector>
#include <filesystem>
#include <memory>
// #include <gtest/gtest.h>
// #include "simulator.hpp"
// #include <vector>
// #include <filesystem>
// #include <memory>
class SimulatorTest : public testing::Test {
protected:
SimulatorTest() :
bodies({
Body(
Position{Decimal(0), Decimal(0), Decimal(0)},
Velocity{Decimal(0), Decimal(0), Decimal(0)},
Mass(1.0),
"body1"
),
Body(
Position{Decimal(1), Decimal(0), Decimal(0)},
Velocity{Decimal(0), Decimal(1), Decimal(0)},
Mass(1.0),
"body2"
)
})
{
simulator = std::make_unique<Simulator>(
bodies,
Decimal(0.1), // step_size
1, // steps_per_save
std::filesystem::path("test_output.json"), // output_file
0, // current_step
true // overwrite_output
);
}
// class SimulatorTest : public testing::Test {
// protected:
// SimulatorTest() :
// bodies({
// Body(
// Position{Decimal(0), Decimal(0), Decimal(0)},
// Velocity{Decimal(0), Decimal(0), Decimal(0)},
// Mass(1.0),
// "body1"
// ),
// Body(
// Position{Decimal(1), Decimal(0), Decimal(0)},
// Velocity{Decimal(0), Decimal(1), Decimal(0)},
// Mass(1.0),
// "body2"
// )
// })
// {
// simulator = std::make_unique<Simulator>(
// bodies,
// Decimal(0.1), // step_size
// 1, // steps_per_save
// std::filesystem::path("test_output.json"), // output_file
// 0, // current_step
// true // overwrite_output
// );
// }
std::vector<Body> bodies;
std::unique_ptr<Simulator> simulator;
};
// std::vector<Body> bodies;
// std::unique_ptr<Simulator> simulator;
// };
TEST_F(SimulatorTest, Step) {
// Take a step
//TODO
}
// TEST_F(SimulatorTest, Step) {
// // Take a step
// //TODO
// }
TEST_F(SimulatorTest, TotalEnergy) {
//TODO
// Decimal initial_energy = simulator->total_energy();
// TEST_F(SimulatorTest, TotalEnergy) {
// //TODO
// // Decimal initial_energy = simulator->total_energy();
// simulator->step(Decimal(0.1));
// // simulator->step(Decimal(0.1));
// Decimal new_energy = simulator->total_energy();
// // Decimal new_energy = simulator->total_energy();
// EXPECT_NEAR(initial_energy, new_energy, 1e-10);
}
// // EXPECT_NEAR(initial_energy, new_energy, 1e-10);
// }