13th International Conference on Membrane Computing - MTA Sztaki

Spiking neural P systems with functional astrocytes
http://projects.congrace.de/exp4j/;
Let us notice that, as we are restricted when defining functions, SNPSFA
are only partially simulated. The following functions are pre-defined, thus
can be used directly, without having to be explicitly defined in the P–Lingua
source file:
• zero(x1) is the identically zero function of arity one;
• identity(x1) is the identity function of arity one;
• pol() is a function template allowing the definition of a polynomial astrocyte
function pol(x 0 , x 1 , . . . , x n , x) of any arity n + 2, n ≥ 0, defined
as follows:
with x i ∈ N, 0 ≤ i ≤ n, x ∈ N;
pol(x 0 , x 1 , . . . , x n , x) = x 0 +
n∑
x i ∗ x i
x 0 , . . . , x n , x arguments take value from the spikes passing through the
operand synapses associated to a given astrocyte ast j at a instant t in
the following way:
⎧
x 0 ← s o j,1 (t)
x 1 ← s o j,2 (t)
⎪⎨
. . .
x n ← s o j,r j−2
(t)
⎪⎩
x ← s o j,r j−1
(t)
i=1
• sub() is a function template allowing the definition of a natural
substraction function sub(x 1 , . . . , x n ) of any arity n greater or equal
than one, defined as follows:
{
x1 − x
sub(x 1 , . . . , x n ) =
2 − · · · − x n when x 1 − x 2 − · · · − x n ≥ 0
0 otherwise
with x i ∈ N, 1 ≤ i ≤ n;
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