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Martin Reinecke
pypocketfft
Commits
189bffbf
Commit
189bffbf
authored
Aug 21, 2019
by
Martin Reinecke
Browse files
don't store second half of unit circle
parent
61a3e544
Changes
1
Hide whitespace changes
Inline
Side-by-side
pocketfft_hdronly.h
View file @
189bffbf
...
...
@@ -438,6 +438,7 @@ template<typename T> class sincos_2pibyn
{
private:
using
Thigh
=
typename
conditional
<
(
sizeof
(
T
)
>
sizeof
(
double
)),
T
,
double
>::
type
;
size_t
sz
;
arr
<
cmplx
<
T
>>
data
;
POCKETFFT_NOINLINE
void
calc_first_octant
(
size_t
den
,
...
...
@@ -474,8 +475,8 @@ template<typename T> class sincos_2pibyn
void
calc_first_quadrant
(
size_t
n
,
cmplx
<
T
>
*
POCKETFFT_RESTRICT
res
)
{
cmplx
<
T
>
*
POCKETFFT_RESTRICT
p
=
res
+
n
/
2
;
// n is always even here
calc_first_octant
(
n
<<
1
,
p
);
arr
<
cmplx
<
T
>
>
p
(
n
/
2
)
;
// n is always even here
calc_first_octant
(
n
<<
1
,
p
.
data
()
);
size_t
ndone
=
(
n
+
2
)
>>
2
;
size_t
i
=
0
,
idx1
=
0
,
idx2
=
ndone
-
1
;
for
(;
i
+
1
<
ndone
;
i
+=
2
,
++
idx1
,
--
idx2
)
...
...
@@ -490,8 +491,8 @@ template<typename T> class sincos_2pibyn
void
calc_first_half
(
size_t
n
,
cmplx
<
T
>
*
POCKETFFT_RESTRICT
res
)
{
int
ndone
=
int
(
n
+
1
)
>>
1
;
cmplx
<
T
>
*
p
=
res
+
(
n
-
1
)
/
2
;
// n is always odd here
calc_first_octant
(
n
<<
2
,
p
);
arr
<
cmplx
<
T
>
>
p
(
(
n
+
1
)
/
2
)
;
// n is always odd here
calc_first_octant
(
n
<<
2
,
p
.
data
()
);
int
i4
=
0
,
in
=
int
(
n
),
i
=
0
;
for
(;
i4
<=
in
-
i4
;
++
i
,
i4
+=
4
)
// octant 0
res
[
i
]
=
p
[
i4
];
...
...
@@ -522,16 +523,7 @@ template<typename T> class sincos_2pibyn
else
for
(
size_t
i
=
1
,
j
=
half
-
1
;
2
*
i
<
half
;
++
i
,
--
j
)
res
[
j
].
Set
(
-
res
[
i
].
r
,
res
[
i
].
i
);
}
void
fill_second_half
(
size_t
n
,
cmplx
<
T
>
*
POCKETFFT_RESTRICT
res
)
{
if
((
n
&
1
)
==
0
)
for
(
size_t
i
=
0
;
i
<
n
/
2
;
++
i
)
res
[
i
+
n
/
2
].
Set
(
-
res
[
i
].
r
,
-
res
[
i
].
i
);
else
for
(
size_t
i
=
1
,
j
=
n
-
1
;
2
*
i
<
n
;
++
i
,
--
j
)
res
[
j
].
Set
(
res
[
i
].
r
,
-
res
[
i
].
i
);
res
[
half
].
Set
(
T
(
-
1
),
T
(
0
));
}
POCKETFFT_NOINLINE
void
sincos_2pibyn_half
(
size_t
n
,
cmplx
<
T
>
*
POCKETFFT_RESTRICT
res
)
...
...
@@ -552,14 +544,18 @@ template<typename T> class sincos_2pibyn
}
public:
POCKETFFT_NOINLINE
sincos_2pibyn
(
size_t
n
,
bool
half
)
:
data
(
n
)
POCKETFFT_NOINLINE
sincos_2pibyn
(
size_t
n
)
:
sz
(
n
),
data
(
n
/
2
+
1
)
{
sincos_2pibyn_half
(
n
,
data
.
data
());
}
cmplx
<
T
>
operator
[](
size_t
idx
)
const
{
sincos_2pibyn_half
(
n
,
data
.
data
());
if
(
!
half
)
fill_second_half
(
n
,
data
.
data
());
if
(
idx
<
data
.
size
())
return
data
[
idx
];
auto
c
=
data
[
sz
-
idx
];
c
.
i
=
-
c
.
i
;
return
c
;
}
cmplx
<
T
>
operator
[](
size_t
idx
)
const
{
return
data
[
idx
];
}
};
struct
util
// hack to avoid duplicate symbols
...
...
@@ -1613,7 +1609,7 @@ template<bool fwd, typename T> void pass_all(T c[], T0 fct) const
void
comp_twiddle
()
{
sincos_2pibyn
<
T0
>
twiddle
(
length
,
false
);
sincos_2pibyn
<
T0
>
twiddle
(
length
);
size_t
l1
=
1
;
size_t
memofs
=
0
;
for
(
size_t
k
=
0
;
k
<
fact
.
size
();
++
k
)
...
...
@@ -2421,7 +2417,7 @@ template<typename T> void radbg(size_t ido, size_t ip, size_t l1,
void
comp_twiddle
()
{
sincos_2pibyn
<
T0
>
twid
(
length
,
true
);
sincos_2pibyn
<
T0
>
twid
(
length
);
size_t
l1
=
1
;
T0
*
ptr
=
mem
.
data
();
for
(
size_t
k
=
0
;
k
<
fact
.
size
();
++
k
)
...
...
@@ -2515,7 +2511,7 @@ template<typename T0> class fftblue
bk
(
mem
.
data
()),
bkf
(
mem
.
data
()
+
n
)
{
/* initialize b_k */
sincos_2pibyn
<
T0
>
tmp
(
2
*
n
,
false
);
sincos_2pibyn
<
T0
>
tmp
(
2
*
n
);
bk
[
0
].
Set
(
1
,
0
);
size_t
coeff
=
0
;
...
...
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