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Lorentz Coordinate System
panguojun edited this page Apr 2, 2025
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The Lorentz Coordinate System is an advanced mathematical framework designed to handle spacetime transformations and relativistic effects in physics simulations. It extends traditional 3D coordinate systems by incorporating time as a complex dimension, enabling natural representation of phenomena like time dilation and length contraction.
This system combines:
- Three orthonormal basis vectors (x, y, z axes)
- A complex time component (representing time power/phase)
- Quaternion-based rotation capabilities
- Unified spacetime representation - Seamlessly combines spatial and temporal dimensions
- Relativistic ready - Built-in support for time dilation and length contraction
- Operator overloads - Intuitive mathematical operations for coordinate transformations
- Quaternion integration - Smooth interoperability with rotational representations
- Physics optimization - Efficient computations for real-time simulations
The system represents coordinates as:
C = { ux, uy, uz, power }
Where:
-
ux,uy,uzform an orthonormal basis for 3D space -
poweris a complex number representing the time dimension transformation
Include the header in your project:
#include "lorentz_coord.hpp"// Default system (aligned with global XYZ)
lorentz_coord defaultFrame;
// System rotated 45° around Y-axis with time factor 0.8
lorentz_coord rotatedFrame(45.0 * DEG2RAD, vec3::UY, complex(0.8, 0));
// From Euler angles
lorentz_coord eulerFrame(0.1, 0.5, 0.2, complex::ONE);
// From quaternion
quaternion q(0.5, 0.5, 0.5, 0.5);
lorentz_coord quatFrame(q, complex(1.0, 0.1));vec3 globalVector(1, 0, 0);
// Transform vector to local frame
vec3 localVector = globalVector / rotatedFrame;
// Transform back to global space
vec3 transformedBack = localVector * rotatedFrame;// Observer far from gravity well
lorentz_coord farObserver(vec3::UX, vec3::UY, vec3::UZ, complex::ONE);
// Observer near black hole (time runs at half speed)
lorentz_coord nearBlackHole(vec3::UX, vec3::UY, vec3::UZ, complex(0.5, 0));
// Event lasting 1 second in local frame
vec4 localEvent(0, 0, 0, 1.0); // (x,y,z,t)
// Compare observed durations
vec4 farObserved = localEvent * farObserver;
vec4 nearObserved = localEvent * nearBlackHole;
std::cout << "Far observer sees duration: " << farObserved.t << std::endl;
std::cout << "Near black hole sees duration: " << nearObserved.t << std::endl;// Frame moving at 0.6c along X-axis
real beta = 0.6;
real gamma = 1.0 / sqrt(1 - beta*beta);
lorentz_coord movingFrame(
vec3(gamma, 0, 0),
vec3(0, 1, 0),
vec3(0, 0, 1),
complex(gamma, 0)
);
// Object moving at 0.5c in moving frame
vec3 localVel(0.5, 0, 0);
// Calculate global velocity
vec3 globalVel = localVel * movingFrame;
std::cout << "Resultant velocity: " << globalVel.length() << "c" << std::endl;// Simulate Schwarzschild metric effects
real schwarzschildRadius = 2 * G * MASS / (c * c);
vec3 position(10 * schwarzschildRadius, 0, 0);
real r = position.length();
// Time dilation factor
real timeFactor = sqrt(1 - schwarzschildRadius/r);
// Create curved spacetime frame
lorentz_coord curvedSpace(
position.normalized(), // Radial direction
vec3::UY.cross(position).normalized(), // Angular direction
vec3::UY, // Vertical direction
complex(timeFactor, 0)
);
// Calculate proper time vs coordinate time
vec4 localEvent(0, 0, 0, 1.0); // 1 second proper time
vec4 globalTime = localEvent * curvedSpace;// Light ray passing near massive object
vec3 lightRay(0, 1, 0).normalized();
// Create warped coordinate system
real warpFactor = calculateWarpFactor(position);
lorentz_coord warpedFrame = calculateWarpedFrame(position);
// Transform light path
vec3 warpedRay = lightRay / warpedFrame;
// Calculate apparent position
vec3 apparentPosition = originalPosition + warpedRay * distance;| Operation | Description |
|---|---|
A * B |
Compose coordinate systems |
v * C |
Transform vector v by C |
C1 / C2 |
Relative transformation between systems |
v / C |
Project vector v onto C's basis |
C.cross(v) |
Cross product with vector |
C1.cross(C2) |
Cross product between systems |
| Method | Description |
|---|---|
to_quaternion() |
Convert to rotation quaternion |
coord_to_eulers() |
Get Euler angles representation |
reversed() |
Get inverse transformation |
The system is optimized for real-time applications:
- Minimal memory footprint (3 vectors + 1 complex)
- Efficient operator implementations
- Avoids full 4x4 matrix operations when possible
- Cache-friendly structure
Contributions to enhance the system are welcome:
- Additional coordinate system types
- More physical effects implementations
- Performance optimizations
- Unit test coverage
The implementation of this module needs to be further verified.