<s>
GNU	B-Language
Octave	I-Language
is	O
a	O
high-level	B-Language
programming	I-Language
language	I-Language
primarily	O
intended	O
for	O
scientific	B-Application
computing	I-Application
and	O
numerical	B-General_Concept
computation	I-General_Concept
.	O
</s>
<s>
Octave	B-Language
helps	O
in	O
solving	O
linear	O
and	O
nonlinear	O
problems	O
numerically	B-General_Concept
,	O
and	O
for	O
performing	O
other	O
numerical	O
experiments	O
using	O
a	O
language	O
that	O
is	O
mostly	O
compatible	O
with	O
MATLAB	B-Language
.	O
</s>
<s>
It	O
may	O
also	O
be	O
used	O
as	O
a	O
batch-oriented	B-General_Concept
language	O
.	O
</s>
<s>
As	O
part	O
of	O
the	B-Application
GNU	I-Application
Project	I-Application
,	O
it	O
is	O
free	B-Application
software	I-Application
under	O
the	O
terms	O
of	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
.	O
</s>
<s>
The	O
program	O
is	O
named	O
after	O
Octave	B-Language
Levenspiel	O
,	O
a	O
former	O
professor	O
of	O
the	O
principal	O
author	O
.	O
</s>
<s>
In	O
addition	O
to	O
use	O
on	O
desktops	O
for	O
personal	O
scientific	B-Application
computing	I-Application
,	O
Octave	B-Language
is	O
used	O
in	O
academia	O
and	O
industry	O
.	O
</s>
<s>
For	O
example	O
,	O
Octave	B-Language
was	O
used	O
on	O
a	O
massive	O
parallel	B-Operating_System
computer	I-Operating_System
at	O
Pittsburgh	O
Supercomputing	O
Center	O
to	O
find	O
vulnerabilities	O
related	O
to	O
guessing	O
social	O
security	O
numbers	O
.	O
</s>
<s>
Acceleration	O
with	O
OpenCL	B-Application
or	O
CUDA	B-Architecture
is	O
also	O
possible	O
with	O
use	O
of	O
GPUs	O
.	O
</s>
<s>
Octave	B-Language
is	O
written	O
in	O
C++	B-Language
using	O
the	O
C++	B-Language
standard	I-Language
library	I-Language
.	O
</s>
<s>
Octave	B-Language
uses	O
an	O
interpreter	B-Application
to	O
execute	O
the	O
Octave	B-Language
scripting	B-Language
language	I-Language
.	O
</s>
<s>
Octave	B-Language
is	O
extensible	O
using	O
dynamically	O
loadable	O
modules	O
.	O
</s>
<s>
Octave	B-Language
interpreter	B-Application
has	O
an	O
OpenGL-based	O
graphics	O
engine	O
to	O
create	O
plots	O
,	O
graphs	O
and	O
charts	O
and	O
to	O
save	O
or	O
print	O
them	O
.	O
</s>
<s>
Alternatively	O
,	O
gnuplot	B-Application
can	O
be	O
used	O
for	O
the	O
same	O
purpose	O
.	O
</s>
<s>
Octave	B-Language
includes	O
a	O
Graphical	B-Application
User	I-Application
Interface	I-Application
(	O
GUI	B-Application
)	O
in	O
addition	O
to	O
the	O
traditional	O
Command	B-Application
Line	I-Application
Interface	I-Application
(	O
CLI	O
)	O
;	O
see	O
#User	O
interfaces	O
for	O
details	O
.	O
</s>
<s>
The	O
Octave	B-Language
language	O
is	O
an	O
interpreted	B-Application
programming	I-Application
language	I-Application
.	O
</s>
<s>
It	O
is	O
a	O
structured	B-Language
programming	I-Language
language	O
(	O
similar	O
to	O
C	B-Language
)	O
and	O
supports	O
many	O
common	O
C	B-Language
standard	I-Language
library	I-Language
functions	O
,	O
and	O
also	O
certain	O
UNIX	B-Application
system	I-Application
calls	O
and	O
functions	O
.	O
</s>
<s>
However	O
,	O
it	O
does	O
not	O
support	O
passing	O
arguments	O
by	O
reference	O
although	O
function	O
arguments	O
are	O
copy-on-write	B-Language
to	O
avoid	O
unnecessary	O
duplication	O
.	O
</s>
<s>
Octave	B-Language
programs	O
consist	O
of	O
a	O
list	O
of	O
function	O
calls	O
or	O
a	O
script	B-Language
.	O
</s>
<s>
The	O
syntax	O
is	O
matrix-based	O
and	O
provides	O
various	O
functions	O
for	O
matrix	B-Application
operations	O
.	O
</s>
<s>
It	O
supports	O
various	O
data	B-General_Concept
structures	I-General_Concept
and	O
allows	O
object-oriented	B-Language
programming	I-Language
.	O
</s>
<s>
Its	O
syntax	O
is	O
very	O
similar	O
to	O
MATLAB	B-Language
,	O
and	O
careful	O
programming	O
of	O
a	O
script	B-Language
will	O
allow	O
it	O
to	O
run	O
on	O
both	O
Octave	B-Language
and	O
MATLAB	B-Language
.	O
</s>
<s>
Because	O
Octave	B-Language
is	O
made	O
available	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
,	O
it	O
may	O
be	O
freely	O
changed	O
,	O
copied	O
and	O
used	O
.	O
</s>
<s>
The	O
program	O
runs	O
on	O
Microsoft	B-Application
Windows	I-Application
and	O
most	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
including	O
Linux	B-Application
,	O
Android	B-Application
,	O
and	O
macOS	B-Application
.	O
</s>
<s>
Typing	O
a	O
TAB	O
character	O
on	O
the	O
command	B-Application
line	I-Application
causes	O
Octave	B-Language
to	O
attempt	O
to	O
complete	O
variable	O
,	O
function	O
,	O
and	O
file	O
names	O
(	O
similar	O
to	O
Bash	B-Operating_System
's	O
tab	O
completion	O
)	O
.	O
</s>
<s>
Octave	B-Language
uses	O
the	O
text	O
before	O
the	O
cursor	O
as	O
the	O
initial	O
portion	O
of	O
the	O
name	O
to	O
complete	O
.	O
</s>
<s>
When	O
running	O
interactively	O
,	O
Octave	B-Language
saves	O
the	O
commands	O
typed	O
in	O
an	O
internal	O
buffer	O
so	O
that	O
they	O
can	O
be	O
recalled	O
and	O
edited	O
.	O
</s>
<s>
Octave	B-Language
includes	O
a	O
limited	O
amount	O
of	O
support	O
for	O
organizing	O
data	O
in	O
structures	O
.	O
</s>
<s>
Octave	B-Language
's	O
&&	O
and	O
||	O
logical	O
operators	O
are	O
evaluated	O
in	O
a	O
short-circuit	O
fashion	O
(	O
like	O
the	O
corresponding	O
operators	O
in	O
the	O
C	B-Language
language	I-Language
)	O
,	O
in	O
contrast	O
to	O
the	O
element-by-element	O
operators	O
&	O
and	O
|	O
.	O
</s>
<s>
Octave	B-Language
includes	O
the	O
C-like	O
increment	O
and	O
decrement	O
operators	O
++	O
and	O
--	O
in	O
both	O
their	O
prefix	O
and	O
postfix	O
forms	O
.	O
</s>
<s>
Octave	B-Language
also	O
does	O
augmented	O
assignment	O
,	O
e.g.	O
</s>
<s>
Octave	B-Language
supports	O
a	O
limited	O
form	O
of	O
exception	B-General_Concept
handling	I-General_Concept
modelled	O
after	O
the	O
of	O
Lisp	B-Language
.	O
</s>
<s>
As	O
a	O
general	O
rule	O
,	O
GNU	B-Language
Octave	I-Language
recognizes	O
as	O
termination	O
of	O
a	O
given	O
block	O
either	O
the	O
keyword	O
end	O
(	O
which	O
is	O
compatible	O
with	O
the	O
MATLAB	B-Language
language	O
)	O
or	O
a	O
more	O
specific	O
keyword	O
endblock	O
or	O
,	O
in	O
some	O
cases	O
,	O
end_block	O
.	O
</s>
<s>
GNU	B-Language
Octave	I-Language
also	O
supports	O
another	O
form	O
of	O
exception	B-General_Concept
handling	I-General_Concept
(	O
compatible	O
with	O
the	O
MATLAB	B-Language
language	O
)	O
:	O
</s>
<s>
Octave	B-Language
has	O
a	O
mechanism	O
for	O
handling	O
functions	O
that	O
take	O
an	O
unspecified	O
number	O
of	O
arguments	O
without	O
explicit	O
upper	O
limit	O
.	O
</s>
<s>
It	O
is	O
also	O
possible	O
to	O
execute	O
Octave	B-Language
code	O
directly	O
in	O
a	O
C++	B-Language
program	I-Language
.	O
</s>
<s>
C	B-Language
and	O
C++	B-Language
code	I-Language
can	O
be	O
integrated	O
into	O
GNU	B-Language
Octave	I-Language
by	O
creating	O
oct	O
files	O
,	O
or	O
using	O
the	O
MATLAB	B-Language
compatible	O
MEX	B-Operating_System
files	I-Operating_System
.	O
</s>
<s>
Octave	B-Language
has	O
been	O
built	O
with	O
MATLAB	B-Language
compatibility	O
in	O
mind	O
,	O
and	O
shares	O
many	O
features	O
with	O
MATLAB	B-Language
:	O
</s>
<s>
Octave	B-Language
treats	O
incompatibility	O
with	O
MATLAB	B-Language
as	O
a	O
bug	B-Error_Name
;	O
therefore	O
,	O
it	O
could	O
be	O
considered	O
a	O
software	O
clone	O
,	O
which	O
does	O
not	O
infringe	O
software	O
copyright	O
as	O
per	O
Lotus	O
v	O
.	O
Borland	O
court	O
case	O
.	O
</s>
<s>
MATLAB	B-Language
scripts	O
from	O
the	O
MathWorks	O
 '	O
FileExchange	O
repository	O
in	O
principle	O
are	O
compatible	O
with	O
Octave	B-Language
.	O
</s>
<s>
However	O
,	O
while	O
they	O
are	O
often	O
provided	O
and	O
uploaded	O
by	O
users	O
under	O
an	O
Octave	B-Language
compatible	O
and	O
proper	O
open	O
source	O
BSD	B-Operating_System
license	I-Operating_System
,	O
the	O
FileExchange	O
Terms	O
of	O
use	O
prohibit	O
any	O
usage	O
beside	O
MathWorks	O
 '	O
proprietary	B-Application
MATLAB	B-Language
.	O
</s>
<s>
Various	O
C-based	B-Language
operators	O
++	O
,	O
--	O
,	O
+	O
=	O
,	O
*	O
=	O
,	O
/	O
=	O
are	O
supported	O
;	O
</s>
<s>
When	O
the	O
variable	O
type	O
is	O
single	O
(	O
a	O
single-precision	O
floating-point	O
number	O
)	O
,	O
Octave	B-Language
calculates	O
the	O
"	O
mean	O
"	O
in	O
the	O
single-domain	O
(	O
MATLAB	B-Language
in	O
double-domain	O
)	O
which	O
is	O
faster	O
but	O
gives	O
less	O
accurate	O
results	O
;	O
</s>
<s>
Functions	O
can	O
be	O
defined	O
within	O
scripts	O
and	O
at	O
the	O
Octave	B-Language
prompt	O
;	O
</s>
<s>
Presence	O
of	O
a	O
do-until	O
loop	O
(	O
similar	O
to	O
do-while	O
in	O
C	B-Language
)	O
.	O
</s>
<s>
Many	O
,	O
but	O
not	O
all	O
,	O
of	O
the	O
numerous	O
MATLAB	B-Language
functions	O
are	O
available	O
in	O
GNU	B-Language
Octave	I-Language
,	O
some	O
of	O
them	O
accessible	O
through	O
packages	O
in	O
.	O
</s>
<s>
The	O
functions	O
available	O
as	O
part	O
of	O
either	O
core	O
Octave	B-Language
or	O
Forge	O
packages	O
are	O
listed	O
.	O
</s>
<s>
A	O
list	O
of	O
unavailable	O
functions	O
is	O
included	O
in	O
the	O
Octave	B-Language
function	O
.	O
</s>
<s>
Unimplemented	O
functions	O
are	O
also	O
listed	O
under	O
many	O
Octave	B-Language
Forge	O
packages	O
in	O
the	O
.	O
</s>
<s>
Octave	B-Language
comes	O
with	O
an	O
official	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
and	O
an	O
integrated	B-Application
development	I-Application
environment	I-Application
(	O
IDE	O
)	O
based	O
on	O
Qt	B-Language
.	O
</s>
<s>
It	O
has	O
been	O
available	O
since	O
Octave	B-Language
3.8	O
,	O
and	O
has	O
become	O
the	O
default	O
interface	O
(	O
over	O
the	O
command	B-Application
line	I-Application
interface	I-Application
)	O
with	O
the	O
release	O
of	O
Octave	B-Language
4.0	O
.	O
</s>
<s>
It	O
was	O
well-received	O
by	O
an	O
EDN	O
contributor	O
,	O
who	O
wrote	O
"[Octave]	O
now	O
has	O
a	O
very	O
workable	O
GUI	B-Application
"	O
in	O
reviewing	O
the	O
then-new	O
GUI	B-Application
in	O
2014	O
.	O
</s>
<s>
Several	O
3rd-party	O
graphical	O
front-ends	O
have	O
also	O
been	O
developed	O
,	O
like	O
ToolboX	B-Application
for	O
coding	O
education	O
.	O
</s>
<s>
With	O
Octave	B-Language
code	O
,	O
the	O
user	O
can	O
create	O
GUI	B-Application
applications	O
.	O
</s>
<s>
Octave	B-Language
also	O
has	O
many	O
packages	O
available	O
.	O
</s>
<s>
Those	O
packages	O
are	O
located	O
at	O
Octave-Forge	O
,	O
or	O
.	O
</s>
<s>
Other	O
free	B-Application
alternatives	O
to	O
MATLAB	B-Language
include	O
Scilab	B-Application
and	O
FreeMat	B-Language
.	O
</s>
<s>
Octave	B-Language
is	O
more	O
compatible	O
with	O
MATLAB	B-Language
than	O
Scilab	B-Application
is	O
,	O
and	O
FreeMat	B-Language
has	O
not	O
been	O
updated	O
since	O
June	O
2013	O
.	O
</s>
