Table 2.

Filters and logical functions implemented in the G-code, with input/output ports and parameters.

Symbol	Name	Input ports	Output ports	Parameters
u(a)	Step function	x	y = 1 if x > a; otherwise y = 0	a
m(a)	Multiplicative function	x	y = ax	a
		$\overrightarrow{v}$	$\overrightarrow{w}=a\cdot \overrightarrow{v}$
h1	Hill function with coefficient 1	x	y = x/(1 + x)
h4	Sigmoid function	x	y = x4/(1 + x4)
	(Hill coefficient 4)
i	Inverse function	x	y = 1/x
s	Sum function	x1,…,xn	$y=\Sigma x_i$
		${\overrightarrow{v}}_1,\dots ,{\overrightarrow{v}}_1$	$\overrightarrow{w}=\Sigma {\overrightarrow{v}}_i$
p	Perpendicular vector	$\overrightarrow{v}$	$\overrightarrow{w}$ such that $\overrightarrow{v}\cdot \overrightarrow{w}=0$
or	Or function	x1,…,xn	y = 1 if $\exists x_i>0$; otherwise y = 0
and	And function	x1,…,xn	y = 1 if $\forall i,x_i>0$; otherwise y = 0
1	One		y = 1
rand	Random vector		A random $\overrightarrow{v}$ of length 1

(x, x_i,y denote ports with a scalar value; $\overrightarrow{v}$, ${\overrightarrow{v}}_i$, $\overrightarrow{w}$ ports with a vectorial value). Functions can be combined to form other more complex functions.