<s>
In	O
feature-oriented	B-Application
software	I-Application
development	I-Application
,	O
feature-oriented	B-Application
software	I-Application
development	I-Application
program	O
cubes	O
(	O
FOSD	B-Application
program	I-Application
cubes	I-Application
)	O
are	O
n-dimensional	O
arrays	O
of	O
functions	O
(	O
program	O
transformations	O
)	O
that	O
represent	O
n-dimensional	O
product	O
lines	O
.	O
</s>
<s>
A	O
software	B-Application
product	I-Application
line	I-Application
(	O
SPL	O
)	O
is	O
a	O
family	O
of	O
related	O
programs	O
.	O
</s>
<s>
Note	O
:	O
program	O
cubes	O
are	O
inspired	O
by	O
tensors	B-Device
and	O
data	O
cubes	O
in	O
databases	O
.	O
</s>
<s>
Both	O
use	O
tensor	B-Device
notations	O
and	O
terminology	O
.	O
</s>
<s>
Also	O
,	O
FOSD	B-Application
metamodels	I-Application
can	O
be	O
viewed	O
as	O
special	O
cases	O
of	O
program	O
cubes	O
.	O
</s>
