<s>
In	O
computer	O
science	O
,	O
an	O
evolution	B-Algorithm
strategy	I-Algorithm
(	O
ES	O
)	O
is	O
an	O
optimization	O
technique	O
based	O
on	O
ideas	O
of	O
evolution	O
.	O
</s>
<s>
It	O
belongs	O
to	O
the	O
general	O
class	O
of	O
evolutionary	O
computation	O
or	O
artificial	B-Algorithm
evolution	I-Algorithm
methodologies	O
.	O
</s>
<s>
The	O
'	O
evolution	B-Algorithm
strategy	I-Algorithm
 '	O
optimization	O
technique	O
was	O
created	O
in	O
the	O
early	O
1960s	O
and	O
developed	O
further	O
in	O
the	O
1970s	O
and	O
later	O
by	O
Ingo	O
Rechenberg	O
,	O
Hans-Paul	O
Schwefel	O
and	O
their	O
co-workers	O
.	O
</s>
<s>
Evolution	B-Algorithm
strategies	I-Algorithm
use	O
natural	O
problem-dependent	O
representations	O
,	O
and	O
primarily	O
mutation	O
and	O
selection	O
,	O
as	O
search	O
operators	O
.	O
</s>
<s>
In	O
common	O
with	O
evolutionary	B-Algorithm
algorithms	I-Algorithm
,	O
the	O
operators	O
are	O
applied	O
in	O
a	O
loop	O
.	O
</s>
<s>
the	O
standard	O
deviation	O
of	O
the	O
normal	O
distribution	O
)	O
is	O
often	O
governed	O
by	O
self-adaptation	O
(	O
see	O
evolution	B-Algorithm
window	I-Algorithm
)	O
.	O
</s>
<s>
Individual	O
step	O
sizes	O
for	O
each	O
coordinate	O
,	O
or	O
correlations	O
between	O
coordinates	O
,	O
which	O
are	O
essentially	O
defined	O
by	O
an	O
underlying	O
covariance	O
matrix	O
,	O
are	O
controlled	O
in	O
practice	O
either	O
by	O
self-adaptation	O
or	O
by	O
covariance	B-Algorithm
matrix	I-Algorithm
adaptation	I-Algorithm
(	O
CMA-ES	B-Algorithm
)	O
.	O
</s>
<s>
The	O
(	O
environmental	O
)	O
selection	O
in	O
evolution	B-Algorithm
strategies	I-Algorithm
is	O
deterministic	O
and	O
only	O
based	O
on	O
the	O
fitness	O
rankings	O
,	O
not	O
on	O
the	O
actual	O
fitness	O
values	O
.	O
</s>
<s>
The	O
simplest	O
evolution	B-Algorithm
strategy	I-Algorithm
operates	O
on	O
a	O
population	O
of	O
size	O
two	O
:	O
the	O
current	O
point	O
(	O
parent	O
)	O
and	O
the	O
result	O
of	O
its	O
mutation	O
.	O
</s>
<s>
For	O
some	O
of	O
these	O
variants	O
,	O
proofs	O
of	O
linear	B-Architecture
convergence	I-Architecture
(	O
in	O
a	O
stochastic	O
sense	O
)	O
have	O
been	O
derived	O
on	O
unimodal	O
objective	O
functions	O
.	O
</s>
<s>
Contemporary	O
derivatives	O
of	O
evolution	B-Algorithm
strategy	I-Algorithm
often	O
use	O
a	O
population	O
of	O
μ	O
parents	O
and	O
recombination	O
as	O
an	O
additional	O
operator	O
,	O
called	O
(μ/	O
ρ+	O
,	O
λ	O
)	O
-ES	O
.	O
</s>
