<s>
Halide	B-Operating_System
is	O
a	O
computer	O
programming	O
language	O
designed	O
for	O
writing	O
digital	B-Algorithm
image	I-Algorithm
processing	I-Algorithm
code	O
that	O
takes	O
advantage	O
of	O
memory	B-General_Concept
locality	I-General_Concept
,	O
vectorized	B-Application
computation	I-Application
and	O
multi-core	O
CPUs	B-Device
and	O
GPUs	B-Architecture
.	O
</s>
<s>
Halide	B-Operating_System
is	O
implemented	O
as	O
an	O
internal	O
domain-specific	B-Language
language	I-Language
(	O
DSL	O
)	O
in	O
C++	B-Language
.	O
</s>
<s>
The	O
main	O
innovation	O
Halide	B-Operating_System
brings	O
is	O
the	O
separation	O
of	O
the	O
algorithm	O
being	O
implemented	O
from	O
its	O
execution	O
schedule	O
,	O
i.e.	O
</s>
<s>
code	O
specifying	O
the	O
loop	O
nesting	B-General_Concept
,	O
parallelization	B-Operating_System
,	O
loop	B-Operating_System
unrolling	I-Operating_System
and	O
vector	B-Operating_System
instruction	I-Operating_System
.	O
</s>
<s>
With	O
Halide	B-Operating_System
,	O
changing	O
the	O
schedule	O
does	O
not	O
require	O
any	O
changes	O
to	O
the	O
algorithm	O
and	O
this	O
allows	O
the	O
programmer	O
to	O
experiment	O
with	O
scheduling	O
and	O
finding	O
the	O
most	O
efficient	O
one	O
.	O
</s>
<s>
The	O
following	O
function	O
defines	O
and	O
sets	O
the	O
schedule	O
for	O
a	O
3×3	O
box	B-Algorithm
filter	I-Algorithm
defined	O
as	O
a	O
series	O
of	O
two	O
3×1	O
passes	O
:	O
</s>
<s>
Google	B-Application
used	O
Halide	B-Operating_System
and	O
TensorFlow	B-Language
for	O
its	O
Pixel	O
2	O
Pixel	B-Device
Visual	I-Device
Core	I-Device
.	O
</s>
<s>
Adobe	O
Photoshop	O
also	O
uses	O
Halide	B-Operating_System
.	O
</s>
<s>
Both	O
Google	B-Application
and	O
Adobe	O
have	O
been	O
involved	O
in	O
Halide	B-Operating_System
research	O
.	O
</s>
