<s>
Chapel	B-Language
,	O
the	O
Cascade	B-Language
High	I-Language
Productivity	I-Language
Language	I-Language
,	O
is	O
a	O
parallel	B-Operating_System
programming	I-Operating_System
language	O
that	O
was	O
developed	O
by	O
Cray	O
,	O
and	O
later	O
by	O
Hewlett	O
Packard	O
Enterprise	O
which	O
acquired	O
Cray	O
.	O
</s>
<s>
It	O
was	O
being	O
developed	O
as	O
part	O
of	O
the	O
Cray	O
Cascade	O
project	O
,	O
a	O
participant	O
in	O
DARPA	O
's	O
High	O
Productivity	O
Computing	O
Systems	O
(	O
HPCS	O
)	O
program	O
,	O
which	O
had	O
the	O
goal	O
of	O
increasing	O
supercomputer	B-Architecture
productivity	O
by	O
2010	O
.	O
</s>
<s>
It	O
is	O
being	O
developed	O
as	O
an	O
open	B-Application
source	I-Application
project	O
,	O
under	O
version	O
2	O
of	O
the	O
Apache	B-Application
license	I-Application
.	O
</s>
<s>
The	O
Chapel	B-Language
compiler	O
is	O
written	O
in	O
C	B-Language
and	O
C++	B-Language
(	O
C++14	B-Language
)	O
.	O
</s>
<s>
the	O
optimizer	O
)	O
is	O
LLVM	B-Application
,	O
written	O
in	O
C++	B-Language
.	O
</s>
<s>
Python	O
3.7	O
or	O
newer	O
is	O
required	O
for	O
some	O
optional	O
components	O
such	O
Chapel	B-Language
’s	O
test	O
system	O
and	O
c2chapel	O
,	O
a	O
tool	O
to	O
generate	O
C	B-Language
bindings	B-Application
for	O
Chapel	B-Language
.	O
</s>
<s>
By	O
default	O
Chapel	B-Language
compiles	O
to	O
binary	O
executables	O
,	O
but	O
it	O
can	O
also	O
compile	O
to	O
C	B-Language
code	O
,	O
and	O
then	O
LLVM	B-Application
is	O
not	O
used	O
.	O
</s>
<s>
Chapel	B-Language
code	O
can	O
be	O
compiled	O
to	O
libraries	O
to	O
be	O
callable	O
from	O
C	B-Language
,	O
or	O
Fortran	B-Application
or	O
e.g.	O
</s>
<s>
Chapel	B-Language
includes	O
preliminary	O
work	O
to	O
target	O
NVidia	O
GPUs	O
.	O
</s>
<s>
Chapel	B-Language
2.0	O
is	O
expected	O
in	O
the	O
next	O
six	O
months	O
.	O
</s>
<s>
Version	O
1.28	O
deprecated	B-General_Concept
a	O
lot	O
of	O
functions	O
,	O
and	O
also	O
syntax	O
,	O
the	O
I/O	B-General_Concept
-operator	O
<~>	O
.	O
</s>
<s>
Chapel	B-Language
aims	O
to	O
improve	O
the	O
programmability	O
of	O
parallel	B-Operating_System
computers	I-Operating_System
in	O
general	O
and	O
the	O
Cascade	O
system	O
in	O
particular	O
,	O
by	O
providing	O
a	O
higher	O
level	O
of	O
expression	O
than	O
current	O
programming	O
languages	O
do	O
and	O
by	O
improving	O
the	O
separation	O
between	O
algorithmic	O
expression	O
and	O
data	B-General_Concept
structure	I-General_Concept
implementation	O
details	O
.	O
</s>
<s>
The	O
language	O
designers	O
aspire	O
for	O
Chapel	B-Language
to	O
bridge	O
the	O
gap	O
between	O
current	O
HPC	B-Architecture
programming	O
practitioners	O
,	O
who	O
they	O
describe	O
as	O
Fortran	B-Application
,	O
C	B-Language
or	O
C++	B-Language
users	O
writing	O
procedural	B-Application
code	I-Application
using	O
technologies	O
like	O
OpenMP	B-Application
and	O
MPI	B-Application
on	O
one	O
side	O
,	O
and	O
newly	O
graduating	O
computer	O
programmers	O
who	O
tend	O
to	O
prefer	O
Java	B-Language
,	O
Python	O
or	O
Matlab	O
with	O
only	O
some	O
of	O
them	O
having	O
experience	O
with	O
C++	B-Language
or	O
C	B-Language
.	O
Chapel	B-Language
should	O
offer	O
the	O
productivity	O
advances	O
offered	O
by	O
the	O
latter	O
suite	O
of	O
languages	O
while	O
not	O
alienating	O
the	O
users	O
of	O
the	O
first	O
.	O
</s>
<s>
Chapel	B-Language
supports	O
a	O
multithreaded	B-General_Concept
parallel	B-Application
programming	I-Application
model	I-Application
at	O
a	O
high	O
level	O
by	O
supporting	O
abstractions	O
for	O
data	B-Operating_System
parallelism	I-Operating_System
,	O
task	B-Operating_System
parallelism	I-Operating_System
,	O
and	O
nested	O
parallelism	B-Operating_System
.	O
</s>
<s>
It	O
enables	O
optimizations	O
for	O
the	O
locality	O
of	O
data	O
and	O
computation	O
in	O
the	O
program	O
via	O
abstractions	O
for	O
data	O
distribution	O
and	O
data-driven	B-Application
placement	O
of	O
subcomputations	O
.	O
</s>
<s>
It	O
allows	O
for	O
code	O
reuse	O
and	O
generality	O
through	O
object-oriented	B-Language
concepts	O
and	O
generic	B-Language
programming	I-Language
features	O
.	O
</s>
<s>
For	O
instance	O
,	O
Chapel	B-Language
allows	O
for	O
the	O
declaration	O
of	O
locales	B-Operating_System
.	O
</s>
<s>
While	O
Chapel	B-Language
borrows	O
concepts	O
from	O
many	O
preceding	O
languages	O
,	O
its	O
parallel	O
concepts	O
are	O
most	O
closely	O
based	O
on	O
ideas	O
from	O
High	B-Language
Performance	I-Language
Fortran	I-Language
(	O
HPF	B-Language
)	O
,	O
ZPL	B-Language
,	O
and	O
the	O
Cray	B-Device
MTA	I-Device
's	O
extensions	O
to	O
Fortran	B-Application
and	O
C	B-Language
.	O
</s>
