<s>
NeuroEvolution	B-Algorithm
of	I-Algorithm
Augmenting	I-Algorithm
Topologies	I-Algorithm
(	O
NEAT	O
)	O
is	O
a	O
genetic	B-Algorithm
algorithm	I-Algorithm
(	O
GA	O
)	O
for	O
the	O
generation	O
of	O
evolving	O
artificial	B-Architecture
neural	I-Architecture
networks	I-Architecture
(	O
a	O
neuroevolution	B-Algorithm
technique	O
)	O
developed	O
by	O
Kenneth	O
Stanley	O
and	O
Risto	O
Miikkulainen	O
in	O
2002	O
while	O
at	O
The	O
University	O
of	O
Texas	O
at	O
Austin	O
.	O
</s>
<s>
Traditionally	O
a	O
neural	B-Architecture
network	I-Architecture
topology	O
is	O
chosen	O
by	O
a	O
human	O
experimenter	O
,	O
and	O
effective	O
connection	O
weight	O
values	O
are	O
learned	O
through	O
a	O
training	O
procedure	O
.	O
</s>
<s>
NEAT	O
is	O
an	O
example	O
of	O
a	O
topology	O
and	O
weight	O
evolving	O
artificial	B-Architecture
neural	I-Architecture
network	I-Architecture
(	O
TWEANN	O
)	O
which	O
attempts	O
to	O
simultaneously	O
learn	O
weight	O
values	O
and	O
an	O
appropriate	O
topology	O
for	O
a	O
neural	B-Architecture
network	I-Architecture
.	O
</s>
<s>
In	O
order	O
to	O
encode	O
the	O
network	O
into	O
a	O
phenotype	O
for	O
the	O
GA	O
,	O
NEAT	O
uses	O
a	O
direct	O
encoding	O
scheme	B-Language
which	O
means	O
every	O
connection	O
and	O
neuron	O
is	O
explicitly	O
represented	O
.	O
</s>
<s>
The	O
NEAT	O
approach	O
begins	O
with	O
a	O
perceptron-like	O
feed-forward	O
network	O
of	O
only	O
input	O
neurons	O
and	O
output	O
neurons	O
.	O
</s>
<s>
The	O
original	O
implementation	O
by	O
Ken	O
Stanley	O
is	O
published	O
under	O
the	O
GPL	B-License
.	O
</s>
<s>
It	O
integrates	O
with	O
Guile	B-Application
,	O
a	O
GNU	O
scheme	B-Language
interpreter	O
.	O
</s>
<s>
In	O
2003	O
Stanley	O
devised	O
an	O
extension	O
to	O
NEAT	O
that	O
allows	O
evolution	O
to	O
occur	O
in	O
real	O
time	O
rather	O
than	O
through	O
the	O
iteration	O
of	O
generations	O
as	O
used	O
by	O
most	O
genetic	B-Algorithm
algorithms	I-Algorithm
.	O
</s>
<s>
HyperNEAT	B-Algorithm
is	O
specialized	O
to	O
evolve	O
large	O
scale	O
structures	O
.	O
</s>
<s>
It	O
was	O
originally	O
based	O
on	O
the	O
CPPN	B-Algorithm
theory	O
and	O
is	O
an	O
active	O
field	O
of	O
research	O
.	O
</s>
<s>
The	O
first	O
video	O
game	O
to	O
implement	O
cgNEAT	O
is	O
Galactic	B-Application
Arms	I-Application
Race	I-Application
,	O
a	O
space-shooter	O
game	O
in	O
which	O
unique	O
particle	O
system	O
weapons	O
are	O
evolved	O
based	O
on	O
player	O
usage	O
statistics	O
.	O
</s>
<s>
Each	O
particle	O
system	O
weapon	O
in	O
the	O
game	O
is	O
controlled	O
by	O
an	O
evolved	O
CPPN	B-Algorithm
,	O
similarly	O
to	O
the	O
evolution	O
technique	O
in	O
the	O
NEAT	O
Particles	O
interactive	O
art	O
program	O
.	O
</s>
