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Computable Coordinate System for Momentum Calculation
panguojun edited this page Jun 11, 2025
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This guide introduces a novel momentum calculation method based on the Computable Coordinate System(CCS) framework. It leverages coordinate system structures and algebraic operations to provide a geometrically intuitive approach for momentum analysis in physics systems.
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Local Coordinate System: Each object has a local frame where scaling
sis linked to massm(e.g.,s = √m). -
Intrinsic Velocity (
v'):$$v' = \sqrt{m} \cdot v \quad \text{(relates physical velocity `v` to intrinsic space)}$$ -
Intrinsic Momentum (
p'):$$p' = \sqrt{m} \cdot v' = m \cdot v = p \quad \text{(consistent with physical momentum)}$$
Setup:
- Object A:
m1 = 1,v1 = 2(local frame:C1) - Object B:
m2 = 4,v2 = 0(local frame:C2)
Step 1: Transform to World Coordinate System
Step 2: Collision Dynamics Using coordinate composition and division to model momentum transfer:
Step 3: Post-Collision Transformation After collision, transform back to local frames:
Verification:
- Total momentum remains conserved:
p1 + p2 = p1' + p2' - Intrinsic space ensures
||v'||maintains energy consistency (see Section 3 of the paper).
| Feature | CCS Approach | Traditional Matrix/Tensor |
|---|---|---|
| Geometric Intuition | Directly models translation/rotation/scaling | Requires abstract tensor operations |
| Computational Efficiency | O(1) for basic operations (e.g., *, /) |
O(n³) for matrix multiplications |
| Conservation Laws | Natural integration with arc length (energy) | Requires separate momentum/energy checks |
| Hierarchical Systems | Native support for parent-child transforms | Complex chain rule for Jacobians |
-
Define Local Frames: Initialize
coordobjects for each physical entity with mass-scaleds. -
Transform Vectors: Use
*and/to convert velocities between frames. -
Compute Momentum: Calculate
p = m * vusing intrinsic velocities in local frames. - Simulate Interactions: Update coordinates during collisions/forces using algebraic operations.
#include <vector>
using namespace std;
// Define coordinate system with mass-scaled scaling
coord create_mass_frame(vec3 origin, vec3 mass) {
coord c;
c.o = origin;
c.s = vec3(sqrt(mass.x), sqrt(mass.y), sqrt(mass.z)); // s = √m
c.ux = vec3(1, 0, 0); // Standard basis vectors
c.uy = vec3(0, 1, 0);
c.uz = vec3(0, 0, 1);
return c;
}
// Calculate intrinsic momentum in world space
vec3 momentum(coord& frame, vec3 local_velocity) {
vec3 world_velocity = local_velocity * frame; // Local to world transform
float mass = dot(frame.s, frame.s); // m = s²
return mass * world_velocity;
}- Classical Mechanics: Elastic/inelastic collisions, rigid body dynamics.
- Geometric Physics: Riemannian manifold-based motion.
- Computer Graphics: Hierarchical character skeletons, physics simulations.