<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
conflict-driven	B-Application
clause	I-Application
learning	I-Application
(	O
CDCL	B-Application
)	O
is	O
an	O
algorithm	O
for	O
solving	O
the	O
Boolean	B-Algorithm
satisfiability	I-Algorithm
problem	I-Algorithm
(	O
SAT	O
)	O
.	O
</s>
<s>
Given	O
a	O
Boolean	O
formula	O
,	O
the	O
SAT	B-Algorithm
problem	I-Algorithm
asks	O
for	O
an	O
assignment	O
of	O
variables	O
so	O
that	O
the	O
entire	O
formula	O
evaluates	O
to	O
true	O
.	O
</s>
<s>
The	O
internal	O
workings	O
of	O
CDCL	B-Application
SAT	O
solvers	O
were	O
inspired	O
by	O
DPLL	B-Application
solvers	I-Application
.	O
</s>
<s>
The	O
main	O
difference	O
between	O
CDCL	B-Application
and	O
DPLL	O
is	O
that	O
CDCL	B-Application
's	O
back	O
jumping	O
is	O
non-chronological	O
.	O
</s>
<s>
Conflict-driven	B-Application
clause	I-Application
learning	I-Application
was	O
proposed	O
by	O
Marques-Silva	O
and	O
Sakallah	O
(	O
1996	O
,	O
1999	O
)	O
and	O
Bayardo	O
and	O
Schrag	O
(	O
1997	O
)	O
.	O
</s>
<s>
The	O
satisfiability	B-Algorithm
problem	I-Algorithm
consists	O
in	O
finding	O
a	O
satisfying	O
assignment	O
for	O
a	O
given	O
formula	O
in	O
conjunctive	B-Application
normal	I-Application
form	I-Application
(	O
CNF	O
)	O
.	O
</s>
<s>
In	O
this	O
small	O
example	O
,	O
one	O
can	O
use	O
brute-force	B-Algorithm
search	I-Algorithm
to	O
try	O
all	O
possible	O
assignments	O
and	O
check	O
if	O
they	O
satisfy	O
the	O
formula	O
.	O
</s>
<s>
But	O
in	O
realistic	O
applications	O
with	O
millions	O
of	O
variables	O
and	O
clauses	O
brute	B-Algorithm
force	I-Algorithm
search	I-Algorithm
is	O
impractical	O
.	O
</s>
<s>
Conflict-driven	B-Application
clause	I-Application
learning	I-Application
works	O
as	O
follows	O
.	O
</s>
<s>
A	O
visual	O
example	O
of	O
CDCL	B-Application
algorithm	O
:	O
</s>
<s>
CDCL	B-Application
SAT	O
solvers	O
implement	O
DPLL	O
,	O
but	O
can	O
learn	O
new	O
clauses	O
and	O
backtrack	O
non-chronologically	O
.	O
</s>
<s>
The	O
main	O
application	O
of	O
CDCL	B-Application
algorithm	O
is	O
in	O
different	O
SAT	O
solvers	O
including	O
:	O
</s>
<s>
The	O
CDCL	B-Application
algorithm	O
has	O
made	O
SAT	O
solvers	O
so	O
powerful	O
that	O
they	O
are	O
being	O
used	O
effectively	O
in	O
several	O
real	O
world	O
application	O
areas	O
like	O
AI	O
planning	O
,	O
bioinformatics	O
,	O
software	O
test	O
pattern	O
generation	O
,	O
software	O
package	O
dependencies	O
,	O
hardware	O
and	O
software	O
model	O
checking	O
,	O
and	O
cryptography	O
.	O
</s>
<s>
Related	O
algorithms	O
to	O
CDCL	B-Application
are	O
the	O
Davis	O
–	O
Putnam	O
algorithm	O
and	O
DPLL	B-Application
algorithm	I-Application
.	O
</s>
<s>
Whereas	O
the	O
DPLL	B-Application
algorithm	I-Application
is	O
OK	O
for	O
randomly	O
generated	O
instances	O
,	O
it	O
is	O
bad	O
for	O
instances	O
generated	O
in	O
practical	O
applications	O
.	O
</s>
<s>
CDCL	B-Application
is	O
a	O
more	O
powerful	O
approach	O
to	O
solve	O
such	O
problems	O
in	O
that	O
applying	O
CDCL	B-Application
provides	O
less	O
state	B-Algorithm
space	I-Algorithm
search	I-Algorithm
in	O
comparison	O
to	O
DPLL	O
.	O
</s>
