2 SUBROUTINE RADB4 (IDO, L1, CC, CH, WA1, WA2, WA3)
3 C***BEGIN PROLOGUE RADB4
5 C***PURPOSE Calculate the fast Fourier transform of subvectors of
7 C***LIBRARY SLATEC (FFTPACK)
8 C***TYPE SINGLE PRECISION (RADB4-S)
9 C***AUTHOR Swarztrauber, P. N., (NCAR)
10 C***ROUTINES CALLED (NONE)
11 C***REVISION HISTORY (YYMMDD)
13 C 830401 Modified to use SLATEC library source file format.
14 C 860115 Modified by Ron Boisvert to adhere to Fortran 77 by
15 C (a) changing dummy array size declarations (1) to (*),
16 C (b) changing definition of variable SQRT2 by using
17 C FORTRAN intrinsic function SQRT instead of a DATA
19 C 881128 Modified by Dick Valent to meet prologue standards.
20 C 890831 Modified array declarations. (WRB)
21 C 891214 Prologue converted to Version 4.0 format. (BAB)
22 C 900402 Added TYPE section. (WRB)
23 C***END PROLOGUE RADB4
24 DIMENSION CC(IDO,4,*), CH(IDO,L1,4), WA1(*), WA2(*), WA3(*)
25 C***FIRST EXECUTABLE STATEMENT RADB4
28 TR1 = CC(1,1,K)-CC(IDO,4,K)
29 TR2 = CC(1,1,K)+CC(IDO,4,K)
30 TR3 = CC(IDO,2,K)+CC(IDO,2,K)
31 TR4 = CC(1,3,K)+CC(1,3,K)
37 IF (IDO-2) 107,105,102
39 IF((IDO-1)/2.LT.L1) GO TO 108
44 TI1 = CC(I,1,K)+CC(IC,4,K)
45 TI2 = CC(I,1,K)-CC(IC,4,K)
46 TI3 = CC(I,3,K)-CC(IC,2,K)
47 TR4 = CC(I,3,K)+CC(IC,2,K)
48 TR1 = CC(I-1,1,K)-CC(IC-1,4,K)
49 TR2 = CC(I-1,1,K)+CC(IC-1,4,K)
50 TI4 = CC(I-1,3,K)-CC(IC-1,2,K)
51 TR3 = CC(I-1,3,K)+CC(IC-1,2,K)
60 CH(I-1,K,2) = WA1(I-2)*CR2-WA1(I-1)*CI2
61 CH(I,K,2) = WA1(I-2)*CI2+WA1(I-1)*CR2
62 CH(I-1,K,3) = WA2(I-2)*CR3-WA2(I-1)*CI3
63 CH(I,K,3) = WA2(I-2)*CI3+WA2(I-1)*CR3
64 CH(I-1,K,4) = WA3(I-2)*CR4-WA3(I-1)*CI4
65 CH(I,K,4) = WA3(I-2)*CI4+WA3(I-1)*CR4
73 TI1 = CC(I,1,K)+CC(IC,4,K)
74 TI2 = CC(I,1,K)-CC(IC,4,K)
75 TI3 = CC(I,3,K)-CC(IC,2,K)
76 TR4 = CC(I,3,K)+CC(IC,2,K)
77 TR1 = CC(I-1,1,K)-CC(IC-1,4,K)
78 TR2 = CC(I-1,1,K)+CC(IC-1,4,K)
79 TI4 = CC(I-1,3,K)-CC(IC-1,2,K)
80 TR3 = CC(I-1,3,K)+CC(IC-1,2,K)
89 CH(I-1,K,2) = WA1(I-2)*CR2-WA1(I-1)*CI2
90 CH(I,K,2) = WA1(I-2)*CI2+WA1(I-1)*CR2
91 CH(I-1,K,3) = WA2(I-2)*CR3-WA2(I-1)*CI3
92 CH(I,K,3) = WA2(I-2)*CI3+WA2(I-1)*CR3
93 CH(I-1,K,4) = WA3(I-2)*CR4-WA3(I-1)*CI4
94 CH(I,K,4) = WA3(I-2)*CI4+WA3(I-1)*CR4
97 111 IF (MOD(IDO,2) .EQ. 1) RETURN
99 TI1 = CC(1,2,K)+CC(1,4,K)
100 TI2 = CC(1,4,K)-CC(1,2,K)
101 TR1 = CC(IDO,1,K)-CC(IDO,3,K)
102 TR2 = CC(IDO,1,K)+CC(IDO,3,K)
103 CH(IDO,K,1) = TR2+TR2
104 CH(IDO,K,2) = SQRT2*(TR1-TI1)
105 CH(IDO,K,3) = TI2+TI2
106 CH(IDO,K,4) = -SQRT2*(TR1+TI1)