3D-Whitestone/System_to_Matlab

Python package to help with the translation from python to matlab and more

System-to-Matlab

This is a small library written to convert Sympy expressions into Matlab code (Funktions, S-Funktions, ...).

Basic functionality

The first thing introduced with this library is a new "type" of variable. These variables are symengine variables but also include some additional functionality.

Dynamic Symbol

There are two types Dynamic and Static Symbols. The difference is that Dynamic Symbols are represented as Funktions of $t$ (e.g. $x(t)$). This is needed if you want to differentiate them.

from System_to_Matlab import DynamicSymbol

ds = DynamicSymbol("x", number_of_variables=2, number_of_derivatives=1).vars

display(ds)

$ \left[ \left[\begin{matrix}x_{1}{\left(t \right)}\x_{2}{\left(t \right)}\end{matrix}\right], \ \left[\begin{matrix}\dot{x}{1}{\left(t \right)}\\dot{x}{2}{\left(t \right)}\end{matrix}\right]\right]$

differentiation

All Dynamic Symbols depend on the variable t.

x = ds[0]
t = DynamicSymbol._derivation_variable
disp(x)

$$ \left[\begin{matrix}x_{1}{\left(t \right)}\x_{2}{\left(t \right)}\end{matrix}\right] $$

disp(se.diff(x, t))

$$ \left[\begin{matrix}\frac{d}{d t} x_{1}{\left(t \right)}\\frac{d}{d t} x_{2}{\left(t \right)}\end{matrix}\right] $$

from System_to_Matlab import diff_t
disp(diff_t(x))

$$ \left[\begin{matrix}\dot{x}{1}{\left(t \right)}\\dot{x}{2}{\left(t \right)}\end{matrix}\right] $$

These variables can be differentiated without any issue. The diff_t function can be used to directly replace the derivative with the corresponding symbol.

Static Symbol

The Static Symbol represents a variable without a dependency.

 ds = StaticSymbol("x", number_of_variables=2).vars
disp(ds)

$$ \left[\begin{matrix}x_{1}\x_{2}\end{matrix}\right] $$