Analog Devices VISUALDSP++ 3.5 Manual page 498

DSP Run-Time Library Reference
The twiddle table is passed in the argument
twiddle factors. The function
n/2
ize the array. If the twiddle table contains more factors than needed for a
particular call on
priately; otherwise it should be 1.
The arguments
future expansion. However, the current version of the function ignores the
argument and always scales the output by
scaling. The function will also set
Algorithm
−
n 1
1
∑
=
c i j ( , )
2
n
=
k 0
where i={0,1,...,n -1}, j={0,1,2,...,n-1}
Domain
Input sequence length
4-82
, then the stride factor has to be set appro-
ifft2d_fr16
and
block_exponent
−
n 1
∑
π
+
2 j i k j l n ( *
a k l ( , ) * e
=
l 0
must be a power of two and at least 16.
n
VisualDSP++ 3.5 C/C++ Compiler and Library Manual
, which must contain at least
w
may be used to initial-
twidfft2d_fr16
scale_method
; this is equivalent to static
n*n
to
block_exponent
* )/
have been added for
.
log2(n)
for ADSP-219x DSPs