<s>
In	O
applied	O
mathematics	O
,	O
the	O
regressive	B-Algorithm
discrete	I-Algorithm
Fourier	I-Algorithm
series	I-Algorithm
(	O
RDFS	O
)	O
is	O
a	O
generalization	O
of	O
the	O
discrete	B-Algorithm
Fourier	I-Algorithm
transform	I-Algorithm
where	O
the	O
Fourier	O
series	O
coefficients	O
are	O
computed	O
in	O
a	O
least	B-Algorithm
squares	I-Algorithm
sense	O
and	O
the	O
period	O
is	O
arbitrary	O
,	O
i.e.	O
,	O
not	O
necessarily	O
equal	O
to	O
the	O
length	O
of	O
the	O
data	O
.	O
</s>
<s>
The	O
least	B-Algorithm
squares	I-Algorithm
solution	O
of	O
the	O
above	O
linear	O
system	O
of	O
equations	O
can	O
be	O
written	O
as	O
:	O
</s>
<s>
The	O
least	B-Algorithm
squares	I-Algorithm
solution	O
may	O
be	O
shown	O
to	O
be	O
:	O
</s>
<s>
 [ 2009 ] 	O
applied	O
a	O
generalized	O
version	O
of	O
the	O
RDFS	O
to	O
tomography	B-Algorithm
reconstruction	O
.	O
</s>
