GNU Octave
4.4.1
A high-level interpreted language, primarily intended for numerical computations, mostly compatible with Matlab
zffti1.f
Go to the documentation of this file.
1
subroutine
zffti1
(n,wa,ifac)
2
implicit double precision
(a-h,o-z)
3
dimension
wa(*) ,ifac(*) ,ntryh(4)
4
data
ntryh(1),ntryh(2),ntryh(3),ntryh(4)/3,4,2,5/
5
nl = n
6
nf = 0
7
j = 0
8
101 j = j+1
9
if
(j-4) 102,102,103
10
102 ntry = ntryh(j)
11
go to
104
12
103 ntry = ntry+2
13
104 nq = nl/ntry
14
nr = nl-ntry*nq
15
if
(nr) 101,105,101
16
105 nf = nf+1
17
ifac(nf+2) = ntry
18
nl = nq
19
if
(ntry .ne. 2)
go to
107
20
if
(nf .eq. 1)
go to
107
21
do
106 i=2,nf
22
ib = nf-i+2
23
ifac(ib+2) = ifac(ib+1)
24
106
continue
25
ifac(3) = 2
26
107
if
(nl .ne. 1)
go to
104
27
ifac(1) = n
28
ifac(2) = nf
29
tpi = 6.28318530717959d0
30
argh = tpi/dble(n)
31
i = 2
32
l1 = 1
33
do
110 k1=1,nf
34
ip = ifac(k1+2)
35
ld = 0
36
l2 = l1*ip
37
ido = n/l2
38
idot = ido+ido+2
39
ipm = ip-1
40
do
109 j=1,ipm
41
i1 = i
42
wa(i-1) = 1.
43
wa(i) = 0.
44
ld = ld+l1
45
fi = 0.
46
argld = dble(ld)*argh
47
do
108 ii=4,idot,2
48
i = i+2
49
fi = fi+1.
50
arg = fi*argld
51
wa(i-1) = cos(arg)
52
wa(i) = sin(arg)
53
108
continue
54
if
(ip .le. 5)
go to
109
55
wa(i1-1) = wa(i-1)
56
wa(i1) = wa(i)
57
109
continue
58
l1 = l2
59
110
continue
60
return
61
end
zffti1
subroutine zffti1(n, wa, ifac)
Definition:
zffti1.f:2
dimension
OCTAVE_EXPORT octave_value_list etc The functions then dimension(columns)
liboctave
external
fftpack
zffti1.f
Generated on Sat Sep 1 2018 14:01:45 for GNU Octave by
1.8.14