<s>
In	O
statistics	O
and	O
data	B-Application
mining	I-Application
,	O
affinity	B-Algorithm
propagation	I-Algorithm
(	O
AP	O
)	O
is	O
a	O
clustering	B-Algorithm
algorithm	I-Algorithm
based	O
on	O
the	O
concept	O
of	O
"	O
message	O
passing	O
"	O
between	O
data	O
points	O
.	O
</s>
<s>
Unlike	O
clustering	B-Algorithm
algorithms	I-Algorithm
such	O
as	O
-means	O
or	O
-medoids	O
,	O
affinity	B-Algorithm
propagation	I-Algorithm
does	O
not	O
require	O
the	O
number	O
of	O
clusters	O
to	O
be	O
determined	O
or	O
estimated	O
before	O
running	O
the	O
algorithm	O
.	O
</s>
<s>
Similar	O
to	O
-medoids	O
,	O
affinity	B-Algorithm
propagation	I-Algorithm
finds	O
"	O
exemplars	O
,	O
"	O
members	O
of	O
the	O
input	O
set	O
that	O
are	O
representative	O
of	O
clusters	O
.	O
</s>
<s>
The	O
inventors	O
of	O
affinity	B-Algorithm
propagation	I-Algorithm
showed	O
it	O
is	O
better	O
for	O
certain	O
computer	O
vision	O
and	O
computational	O
biology	O
tasks	O
,	O
e.g.	O
</s>
<s>
clustering	O
of	O
pictures	O
of	O
human	O
faces	O
and	O
identifying	O
regulated	O
transcripts	O
,	O
than	O
-means	O
,	O
even	O
when	O
-means	O
was	O
allowed	O
many	O
random	O
restarts	O
and	O
initialized	O
using	O
PCA	B-Application
.	O
</s>
<s>
A	O
study	O
comparing	O
affinity	B-Algorithm
propagation	I-Algorithm
and	O
Markov	B-General_Concept
clustering	I-General_Concept
on	O
protein	O
interaction	O
graph	O
partitioning	O
found	O
Markov	B-General_Concept
clustering	I-General_Concept
to	O
work	O
better	O
for	O
that	O
problem	O
.	O
</s>
<s>
A	O
semi-supervised	O
variant	O
has	O
been	O
proposed	O
for	O
text	B-Algorithm
mining	I-Algorithm
applications	O
.	O
</s>
<s>
Another	O
recent	O
application	O
was	O
in	O
economics	O
,	O
when	O
the	O
affinity	B-Algorithm
propagation	I-Algorithm
was	O
used	O
to	O
find	O
some	O
temporal	O
patterns	O
in	O
the	O
output	O
multipliers	O
of	O
the	O
US	O
economy	O
between	O
1997	O
and	O
2017	O
.	O
</s>
<s>
A	O
Java	B-Language
implementation	O
is	O
included	O
in	O
the	O
ELKI	B-Language
data	B-Application
mining	I-Application
framework	O
.	O
</s>
<s>
A	O
Julia	B-Application
implementation	O
of	O
affinity	B-Algorithm
propagation	I-Algorithm
is	O
contained	O
in	O
Julia	B-Application
Statistics	O
's	O
Clustering.jl	O
package	O
.	O
</s>
<s>
A	O
Python	B-Language
version	O
is	O
part	O
of	O
the	O
scikit-learn	B-Application
library	O
.	O
</s>
<s>
An	O
R	B-Language
implementation	O
is	O
available	O
in	O
the	O
"	O
apcluster	O
"	O
package	O
.	O
</s>
