1 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
---|
2 | ! |
---|
3 | ! FFTPACK 5.0 |
---|
4 | ! |
---|
5 | ! Authors: Paul N. Swarztrauber and Richard A. Valent |
---|
6 | ! |
---|
7 | ! $Id: rfftb1.f,v 1.2 2004/06/15 21:29:20 rodney Exp $ |
---|
8 | ! |
---|
9 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
---|
10 | |
---|
11 | SUBROUTINE RFFTB1 (N,IN,C,CH,WA,FAC) |
---|
12 | REAL CH(*), C(IN,*), WA(N) ,FAC(15) |
---|
13 | ! |
---|
14 | NF = FAC(2) |
---|
15 | NA = 0 |
---|
16 | DO 10 K1=1,NF |
---|
17 | IP = FAC(K1+2) |
---|
18 | NA = 1-NA |
---|
19 | IF(IP .LE. 5) GO TO 10 |
---|
20 | IF(K1 .EQ. NF) GO TO 10 |
---|
21 | NA = 1-NA |
---|
22 | 10 END DO |
---|
23 | HALF = .5 |
---|
24 | HALFM = -.5 |
---|
25 | MODN = MOD(N,2) |
---|
26 | NL = N-2 |
---|
27 | IF(MODN .NE. 0) NL = N-1 |
---|
28 | IF (NA .EQ. 0) GO TO 120 |
---|
29 | CH(1) = C(1,1) |
---|
30 | CH(N) = C(1,N) |
---|
31 | DO 118 J=2,NL,2 |
---|
32 | CH(J) = HALF*C(1,J) |
---|
33 | CH(J+1) = HALFM*C(1,J+1) |
---|
34 | 118 END DO |
---|
35 | GO TO 124 |
---|
36 | 120 DO 122 J=2,NL,2 |
---|
37 | C(1,J) = HALF*C(1,J) |
---|
38 | C(1,J+1) = HALFM*C(1,J+1) |
---|
39 | 122 END DO |
---|
40 | 124 L1 = 1 |
---|
41 | IW = 1 |
---|
42 | DO 116 K1=1,NF |
---|
43 | IP = FAC(K1+2) |
---|
44 | L2 = IP*L1 |
---|
45 | IDO = N/L2 |
---|
46 | IDL1 = IDO*L1 |
---|
47 | IF (IP .NE. 4) GO TO 103 |
---|
48 | IX2 = IW+IDO |
---|
49 | IX3 = IX2+IDO |
---|
50 | IF (NA .NE. 0) GO TO 101 |
---|
51 | CALL R1F4KB (IDO,L1,C,IN,CH,1,WA(IW),WA(IX2),WA(IX3)) |
---|
52 | GO TO 102 |
---|
53 | 101 CALL R1F4KB (IDO,L1,CH,1,C,IN,WA(IW),WA(IX2),WA(IX3)) |
---|
54 | 102 NA = 1-NA |
---|
55 | GO TO 115 |
---|
56 | 103 IF (IP .NE. 2) GO TO 106 |
---|
57 | IF (NA .NE. 0) GO TO 104 |
---|
58 | CALL R1F2KB (IDO,L1,C,IN,CH,1,WA(IW)) |
---|
59 | GO TO 105 |
---|
60 | 104 CALL R1F2KB (IDO,L1,CH,1,C,IN,WA(IW)) |
---|
61 | 105 NA = 1-NA |
---|
62 | GO TO 115 |
---|
63 | 106 IF (IP .NE. 3) GO TO 109 |
---|
64 | IX2 = IW+IDO |
---|
65 | IF (NA .NE. 0) GO TO 107 |
---|
66 | ! rav CALL RIF3KB (IDO,L1,C,IN,CH,1,WA(IW),WA(IX2)) |
---|
67 | CALL R1F3KB (IDO,L1,C,IN,CH,1,WA(IW),WA(IX2)) |
---|
68 | GO TO 108 |
---|
69 | 107 CALL R1F3KB (IDO,L1,CH,1,C,IN,WA(IW),WA(IX2)) |
---|
70 | 108 NA = 1-NA |
---|
71 | GO TO 115 |
---|
72 | 109 IF (IP .NE. 5) GO TO 112 |
---|
73 | IX2 = IW+IDO |
---|
74 | IX3 = IX2+IDO |
---|
75 | IX4 = IX3+IDO |
---|
76 | IF (NA .NE. 0) GO TO 110 |
---|
77 | CALL R1F5KB (IDO,L1,C,IN,CH,1,WA(IW),WA(IX2), & |
---|
78 | & WA(IX3),WA(IX4)) |
---|
79 | GO TO 111 |
---|
80 | 110 CALL R1F5KB (IDO,L1,CH,1,C,IN,WA(IW),WA(IX2), & |
---|
81 | & WA(IX3),WA(IX4)) |
---|
82 | 111 NA = 1-NA |
---|
83 | GO TO 115 |
---|
84 | 112 IF (NA .NE. 0) GO TO 113 |
---|
85 | ! rav CALL RIFGKB (IDO,IP,L1,IDL1,C,C,C,IN,CH,CH,1,WA(IW)) |
---|
86 | CALL R1FGKB (IDO,IP,L1,IDL1,C,C,C,IN,CH,CH,1,WA(IW)) |
---|
87 | GO TO 114 |
---|
88 | ! rav 113 CALL RIFGKB (IDO,IP,L1,IDL1,CH,CH,CH,1,C,C,IN,WA(IW)) |
---|
89 | 113 CALL R1FGKB (IDO,IP,L1,IDL1,CH,CH,CH,1,C,C,IN,WA(IW)) |
---|
90 | 114 IF (IDO .EQ. 1) NA = 1-NA |
---|
91 | 115 L1 = L2 |
---|
92 | IW = IW+(IP-1)*IDO |
---|
93 | 116 END DO |
---|
94 | RETURN |
---|
95 | END |
---|