<s>
Convex	O
Over	O
and	O
Under	O
ENvelopes	O
for	O
Nonlinear	O
Estimation	O
(	O
Couenne	B-Application
)	O
is	O
an	O
open-source	B-Application
library	O
for	O
solving	O
global	O
optimization	O
problems	O
,	O
also	O
termed	O
mixed	O
integer	O
nonlinear	O
optimization	O
problems	O
.	O
</s>
<s>
For	O
solving	O
these	O
problems	O
,	O
Couenne	B-Application
uses	O
a	O
reformulation	O
procedure	O
and	O
provides	O
a	O
linear	B-Algorithm
programming	I-Algorithm
approximation	O
of	O
any	O
nonconvex	O
optimization	O
problem	O
.	O
</s>
<s>
Couenne	B-Application
is	O
an	O
implementation	O
of	O
a	O
branch-and-bound	B-Algorithm
where	O
every	O
subproblem	O
is	O
solved	O
by	O
constructing	O
a	O
linear	B-Algorithm
programming	I-Algorithm
relaxation	O
to	O
obtain	O
a	O
lower	O
bound	O
.	O
</s>
<s>
It	O
requires	O
the	O
input	O
to	O
be	O
specified	O
in	O
A	O
Mathematical	O
Programming	O
Language	O
(	O
AMPL	B-Language
)	O
.nl	B-Application
format	I-Application
,	O
so	O
as	O
to	O
be	O
used	O
from	O
AMPL	B-Language
,	O
and	O
writes	O
as	O
an	O
output	O
a	O
file	O
.sol	O
containing	O
the	O
best	O
solution	O
found	O
until	O
that	O
moment	O
(	O
if	O
the	O
optimization	O
is	O
interrupted	O
)	O
or	O
the	O
global	O
optimum	O
if	O
it	O
completes	O
without	O
interruption	O
.	O
</s>
<s>
The	O
development	O
of	O
Couenne	B-Application
began	O
in	O
2006	O
within	O
a	O
collaboration	O
between	O
IBM	O
and	O
Carnegie	O
Mellon	O
University	O
.	O
</s>
<s>
It	O
is	O
open-source	B-Application
software	I-Application
and	O
is	O
currently	O
released	O
under	O
the	O
Eclipse	B-License
Public	I-License
License	I-License
v1.0	O
.	O
</s>
<s>
The	O
source	O
code	O
is	O
available	O
for	O
download	O
in	O
the	O
Computational	O
Infrastructure	O
for	O
Operations	O
Research	O
COIN-OR	B-Application
repository	O
and	O
on	O
GitHub	O
.	O
</s>
<s>
Couenne	B-Application
uses	O
other	O
packages	O
both	O
in	O
COIN-OR	B-Application
(	O
CBC	O
,	O
CLP	O
,	O
COIN-OR	B-Application
OSI	O
,	O
COIN-OR	B-Application
Bonmin	O
,	O
COIN-OR	B-Application
Cgl	O
,	O
Interior	O
Point	O
OPTimizer	O
(	O
IPOPT	B-Algorithm
)	O
)	O
and	O
outside	O
(	O
LAPACK	B-Application
,	O
Basic	B-Application
Linear	I-Application
Algebra	I-Application
Subprograms	I-Application
(	O
BLAS	B-Application
)	O
,	O
MUltifrontal	O
Massively	O
Parallel	O
sparse	O
direct	O
Solver	O
(	O
MUMPS	B-Application
)	O
,	O
Nauty	O
,	O
Solving	O
Constraint	O
Integer	O
Programs	O
(	O
SCIP	O
)	O
,	O
SoPlex	O
)	O
.	O
</s>
