MATLAB/Octave Code Generation

Generate MATLAB/GNU Octave simulation scripts with built-in visualization.

Features

Multiple ODE solvers: ode45, ode23, ode15s, ode113, ode23s
Publication-quality plots: Time histories, phase space, energy conservation
Nested function structure: Parameters accessible without globals
CSV export: Automatic results file with energy column
Octave compatible: Works with GNU Octave 5.0+

Basic Usage

from mechanics_dsl.codegen.matlab import MatlabGenerator
import sympy as sp

theta, g, l = sp.symbols('theta g l')

gen = MatlabGenerator(
    system_name="pendulum",
    coordinates=["theta"],
    parameters={"g": 9.81, "l": 1.0},
    initial_conditions={"theta": 0.5, "theta_dot": 0.0},
    equations={"theta_ddot": -g/l * sp.sin(theta)},
    solver="ode45"
)
gen.generate("pendulum.m")

Parameters

solver: MATLAB ODE solver (default: ode45)
abstol: Absolute tolerance (default: 1e-8)
reltol: Relative tolerance (default: 1e-6)
generate_simulink: Generate Simulink model (default: False)

Supported solvers: ode45, ode23, ode15s, ode113, ode23s

Running in MATLAB

>> results = pendulum();
>> plot(results.t, results.y(:,1));

Running in GNU Octave

octave --eval "pendulum"

Generated Code Structure

The generated .m file contains:

Main function: Configuration, ODE solving, results packaging
``equations_of_motion``: Nested function with parameter access
``compute_energy``: Mechanical energy computation
``plot_results``: Time history subplots saved as PNG
``plot_phase_space``: Phase portrait with start/end markers
``plot_energy``: Energy conservation plot with drift annotation
``export_csv``: Results export with header

Output Files

After running, the script produces:

{system_name}_time_history.png — Position and velocity plots
{system_name}_phase_space.png — Phase portrait
{system_name}_energy.png — Energy conservation
{system_name}_results.csv — Numerical results

Solver Selection Guide

Solver	Best For
`ode45`	General non-stiff problems (default)
`ode23`	Crude tolerances, fast evaluation
`ode15s`	Stiff systems
`ode113`	High accuracy, smooth problems
`ode23s`	Stiff with constant mass matrix