1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
|
c
c-----------------------------------------------------------------------
c main program: test program for fft subroutines
c author: l r rabiner
c bell laboratories, murray hill, new jersey, 07974
c input: randomly chosen sequences to test fft subroutines
c for sequences with special properties
c n is the fft length (n must be a power of 2)
c 2<= n <= 4096
c-----------------------------------------------------------------------
c
dimension x(4098), y(4098)
c
c define i/0 device codes
c input: input to this program is user-interactive
c that is - a question is written on the user
c terminal (iout1) ad the user types in the answer.
c
c output: all output is written on the standard
c output unit (iout2).
c
ind = i1mach(1)
iout1 = i1mach(4)
iout2 = i1mach(2)
c
c read in analysis size for fft
c
10 write (iout1,9999)
9999 format (30h fft size(2.le.n.le.4096)(i4)=)
read (ind,9998) n
9998 format (i4)
if (n.eq.0) stop
do 20 i=1,12
itest = 2**i
if (n.eq.itest) go to 30
20 continue
write (iout1,9997)
9997 format (45h n is not a power of 2 in the range 2 to 4096)
go to 10
30 write (iout2,9996) n
9996 format (11h testing n=, i5, 17h random sequences)
write (iout2,9992)
np2 = n + 2
no2 = n/2
no2p1 = no2 + 1
no4 = n/4
no4p1 = no4 + 1
c
c create symmetrical sequence of size n
c
do 40 i=2,no2
x(i) = uni(0) - 0.5
ind1 = np2 - i
x(ind1) = x(i)
40 continue
x(1) = uni(0) - 0.5
x(no2p1) = uni(0) - 0.5
do 50 i=1,no2p1
y(i) = x(i)
50 continue
write (iout2,9995)
9995 format (28h original symmetric sequence)
write (iout2,9993) (x(i),i=1,n)
write (iout2,9992)
c
c compute true fft of n point sequence
c
call fast(x, n)
write (iout2,9994) n
9994 format (1h , i4, 32h point fft of symmetric sequence)
write (iout2,9993) (x(i),i=1,np2)
9993 format (1h , 5e13.5)
write (iout2,9992)
9992 format (1h /1h )
c
c use subroutine fftsym to obtain dft from no2 point fft
c
do 60 i=1,no2p1
x(i) = y(i)
60 continue
call fftsym(x, n, y)
write (iout2,9991)
9991 format (17h output of fftsym)
write (iout2,9993) (x(i),i=1,no2p1)
write (iout2,9992)
c
c use subroutine iftsym to obtain original sequence from no2 point dft
c
call iftsym(x, n, y)
write (iout2,9990)
9990 format (17h output of iftsym)
write (iout2,9993) (x(i),i=1,no2p1)
write (iout2,9992)
c
c create antisymmetric n point sequence
c
do 70 i=2,no2
x(i) = uni(0) - 0.5
ind1 = np2 - i
x(ind1) = -x(i)
70 continue
x(1) = 0.
x(no2p1) = 0.
do 80 i=1,no2p1
y(i) = x(i)
80 continue
write (iout2,9989)
9989 format (32h original antisymmetric sequence)
write (iout2,9993) (x(i),i=1,n)
write (iout2,9992)
c
c obtain n point dft of antisymmetric sequence
c
call fast(x, n)
write (iout2,9988) n
9988 format (1h , i4, 36h point fft of antisymmetric sequence)
write (iout2,9993) (x(i),i=1,np2)
write (iout2,9992)
c
c use subroutine fftasm to obtain dft from no2 point fft
c
do 90 i=1,no2
x(i) = y(i)
90 continue
call fftasm(x, n, y)
write (iout2,9987)
9987 format (17h output of fftasm)
write (iout2,9993) (x(i),i=1,no2p1)
write (iout2,9992)
c
c use subroutine iftasm to obtain original sequence from no2 point dft
c
call iftasm(x, n, y)
write (iout2,9986)
9986 format (17h output of iftasm)
write (iout2,9993) (x(i),i=1,no2)
write (iout2,9992)
c
c create sequence with only odd harmonics--begin in frequency domain
c
do 100 i=1,np2,2
x(i) = 0.
x(i+1) = 0.
if (mod(i,4).eq.1) go to 100
x(i) = uni(0) - 0.5
x(i+1) = uni(0) - 0.5
if (n.eq.2) x(i+1) = 0.
100 continue
write (iout2,9985) n
9985 format (1h , i4, 35h point fft of odd harmonic sequence)
write (iout2,9993) (x(i),i=1,np2)
write (iout2,9992)
c
c transform back to time sequence
c
call fsst(x, n)
write (iout2,9984)
9984 format (31h original odd harmonic sequence)
write (iout2,9993) (x(i),i=1,n)
write (iout2,9992)
c
c use subroutine fftohm to obtain dft from no2 point fft
c
call fftohm(x, n)
write (iout2,9983)
9983 format (17h output of fftohm)
write (iout2,9993) (x(i),i=1,no2)
write (iout2,9992)
c
c use subroutine iftohm to obtain original sequence from no2 point dft
c
call iftohm(x, n)
write (iout2,9982)
9982 format (17h output of iftohm)
write (iout2,9993) (x(i),i=1,no2)
write (iout2,9992)
c
c create sequence with only real valued odd harmonics
c
do 110 i=1,np2,2
x(i) = 0.
x(i+1) = 0.
if (mod(i,4).eq.1) go to 110
x(i) = uni(0) - 0.5
110 continue
write (iout2,9981) n
9981 format (1h , i4, 45h point fft of odd harmonic, symmetric sequenc,
* 1he)
write (iout2,9993) (x(i),i=1,np2)
write (iout2,9992)
c
c transform back to time sequence
c
call fsst(x, n)
write (iout2,9980)
9980 format (42h original odd harmonic, symmetric sequence)
write (iout2,9993) (x(i),i=1,n)
write (iout2,9992)
c
c use subroutine fftsoh to obtain dft from no4 point fft
c
call fftsoh(x, n, y)
write (iout2,9979)
9979 format (17h output of fftsoh)
write (iout2,9993) (x(i),i=1,no4)
write (iout2,9992)
c
c use subroutine iftsoh to obtain original sequence from no4 point dft
c
call iftsoh(x, n, y)
write (iout2,9978)
9978 format (17h output of iftsoh)
write (iout2,9993) (x(i),i=1,no4)
write (iout2,9992)
c
c create sequence with only imaginary valued odd harmonics--begin
c in frequency domain
c
do 120 i=1,np2,2
x(i) = 0.
x(i+1) = 0.
if (mod(i,4).eq.1) go to 120
x(i+1) = uni(0) - 0.5
120 continue
write (iout2,9977) n
9977 format (1h , i4, 41h point fft of odd harmonic, antisymmetric,
* 9h sequence)
write (iout2,9993) (x(i),i=1,np2)
write (iout2,9992)
c
c transform back to time sequence
c
call fsst(x, n)
write (iout2,9976)
9976 format (46h original odd harmonic, antisymmetric sequence)
write (iout2,9993) (x(i),i=1,n)
write (iout2,9992)
c
c use subroutine fftaoh to obtain dft from no4 point fft
c
call fftaoh(x, n, y)
write (iout2,9975)
9975 format (17h output of fftaoh)
write (iout2,9993) (x(i),i=1,no4)
write (iout2,9992)
c
c use subroutine iftaoh to obtain original sequence from n/4 point dft
c
call iftaoh(x, n, y)
write (iout2,9974)
9974 format (17h output of iftaoh)
write (iout2,9993) (x(i),i=1,no4p1)
write (iout2,9992)
c
c begin a new page
c
write (iout2,9973)
9973 format (1h1)
go to 10
end
|
