*DECK RADBG SUBROUTINE RADBG (IDO, IP, L1, IDL1, CC, C1, C2, CH, CH2, WA) C***BEGIN PROLOGUE RADBG C***SUBSIDIARY C***PURPOSE Calculate the fast Fourier transform of subvectors of C arbitrary length. C***LIBRARY SLATEC (FFTPACK) C***TYPE SINGLE PRECISION (RADBG-S) C***AUTHOR Swarztrauber, P. N., (NCAR) C***ROUTINES CALLED (NONE) C***REVISION HISTORY (YYMMDD) C 790601 DATE WRITTEN C 830401 Modified to use SLATEC library source file format. C 860115 Modified by Ron Boisvert to adhere to Fortran 77 by C (a) changing dummy array size declarations (1) to (*), C (b) changing references to intrinsic function FLOAT C to REAL, and C (c) changing definition of variable TPI by using C FORTRAN intrinsic function ATAN instead of a DATA C statement. C 881128 Modified by Dick Valent to meet prologue standards. C 890531 Changed all specific intrinsics to generic. (WRB) C 890831 Modified array declarations. (WRB) C 891214 Prologue converted to Version 4.0 format. (BAB) C 900402 Added TYPE section. (WRB) C***END PROLOGUE RADBG DIMENSION CH(IDO,L1,*), CC(IDO,IP,*), C1(IDO,L1,*), + C2(IDL1,*), CH2(IDL1,*), WA(*) C***FIRST EXECUTABLE STATEMENT RADBG TPI = 8.*ATAN(1.) ARG = TPI/IP DCP = COS(ARG) DSP = SIN(ARG) IDP2 = IDO+2 NBD = (IDO-1)/2 IPP2 = IP+2 IPPH = (IP+1)/2 IF (IDO .LT. L1) GO TO 103 DO 102 K=1,L1 DO 101 I=1,IDO CH(I,K,1) = CC(I,1,K) 101 CONTINUE 102 CONTINUE GO TO 106 103 DO 105 I=1,IDO DO 104 K=1,L1 CH(I,K,1) = CC(I,1,K) 104 CONTINUE 105 CONTINUE 106 DO 108 J=2,IPPH JC = IPP2-J J2 = J+J DO 107 K=1,L1 CH(1,K,J) = CC(IDO,J2-2,K)+CC(IDO,J2-2,K) CH(1,K,JC) = CC(1,J2-1,K)+CC(1,J2-1,K) 107 CONTINUE 108 CONTINUE IF (IDO .EQ. 1) GO TO 116 IF (NBD .LT. L1) GO TO 112 DO 111 J=2,IPPH JC = IPP2-J DO 110 K=1,L1 CDIR$ IVDEP DO 109 I=3,IDO,2 IC = IDP2-I CH(I-1,K,J) = CC(I-1,2*J-1,K)+CC(IC-1,2*J-2,K) CH(I-1,K,JC) = CC(I-1,2*J-1,K)-CC(IC-1,2*J-2,K) CH(I,K,J) = CC(I,2*J-1,K)-CC(IC,2*J-2,K) CH(I,K,JC) = CC(I,2*J-1,K)+CC(IC,2*J-2,K) 109 CONTINUE 110 CONTINUE 111 CONTINUE GO TO 116 112 DO 115 J=2,IPPH JC = IPP2-J CDIR$ IVDEP DO 114 I=3,IDO,2 IC = IDP2-I DO 113 K=1,L1 CH(I-1,K,J) = CC(I-1,2*J-1,K)+CC(IC-1,2*J-2,K) CH(I-1,K,JC) = CC(I-1,2*J-1,K)-CC(IC-1,2*J-2,K) CH(I,K,J) = CC(I,2*J-1,K)-CC(IC,2*J-2,K) CH(I,K,JC) = CC(I,2*J-1,K)+CC(IC,2*J-2,K) 113 CONTINUE 114 CONTINUE 115 CONTINUE 116 AR1 = 1. AI1 = 0. DO 120 L=2,IPPH LC = IPP2-L AR1H = DCP*AR1-DSP*AI1 AI1 = DCP*AI1+DSP*AR1 AR1 = AR1H DO 117 IK=1,IDL1 C2(IK,L) = CH2(IK,1)+AR1*CH2(IK,2) C2(IK,LC) = AI1*CH2(IK,IP) 117 CONTINUE DC2 = AR1 DS2 = AI1 AR2 = AR1 AI2 = AI1 DO 119 J=3,IPPH JC = IPP2-J AR2H = DC2*AR2-DS2*AI2 AI2 = DC2*AI2+DS2*AR2 AR2 = AR2H DO 118 IK=1,IDL1 C2(IK,L) = C2(IK,L)+AR2*CH2(IK,J) C2(IK,LC) = C2(IK,LC)+AI2*CH2(IK,JC) 118 CONTINUE 119 CONTINUE 120 CONTINUE DO 122 J=2,IPPH DO 121 IK=1,IDL1 CH2(IK,1) = CH2(IK,1)+CH2(IK,J) 121 CONTINUE 122 CONTINUE DO 124 J=2,IPPH JC = IPP2-J DO 123 K=1,L1 CH(1,K,J) = C1(1,K,J)-C1(1,K,JC) CH(1,K,JC) = C1(1,K,J)+C1(1,K,JC) 123 CONTINUE 124 CONTINUE IF (IDO .EQ. 1) GO TO 132 IF (NBD .LT. L1) GO TO 128 DO 127 J=2,IPPH JC = IPP2-J DO 126 K=1,L1 CDIR$ IVDEP DO 125 I=3,IDO,2 CH(I-1,K,J) = C1(I-1,K,J)-C1(I,K,JC) CH(I-1,K,JC) = C1(I-1,K,J)+C1(I,K,JC) CH(I,K,J) = C1(I,K,J)+C1(I-1,K,JC) CH(I,K,JC) = C1(I,K,J)-C1(I-1,K,JC) 125 CONTINUE 126 CONTINUE 127 CONTINUE GO TO 132 128 DO 131 J=2,IPPH JC = IPP2-J DO 130 I=3,IDO,2 DO 129 K=1,L1 CH(I-1,K,J) = C1(I-1,K,J)-C1(I,K,JC) CH(I-1,K,JC) = C1(I-1,K,J)+C1(I,K,JC) CH(I,K,J) = C1(I,K,J)+C1(I-1,K,JC) CH(I,K,JC) = C1(I,K,J)-C1(I-1,K,JC) 129 CONTINUE 130 CONTINUE 131 CONTINUE 132 CONTINUE IF (IDO .EQ. 1) RETURN DO 133 IK=1,IDL1 C2(IK,1) = CH2(IK,1) 133 CONTINUE DO 135 J=2,IP DO 134 K=1,L1 C1(1,K,J) = CH(1,K,J) 134 CONTINUE 135 CONTINUE IF (NBD .GT. L1) GO TO 139 IS = -IDO DO 138 J=2,IP IS = IS+IDO IDIJ = IS DO 137 I=3,IDO,2 IDIJ = IDIJ+2 DO 136 K=1,L1 C1(I-1,K,J) = WA(IDIJ-1)*CH(I-1,K,J)-WA(IDIJ)*CH(I,K,J) C1(I,K,J) = WA(IDIJ-1)*CH(I,K,J)+WA(IDIJ)*CH(I-1,K,J) 136 CONTINUE 137 CONTINUE 138 CONTINUE GO TO 143 139 IS = -IDO DO 142 J=2,IP IS = IS+IDO DO 141 K=1,L1 IDIJ = IS CDIR$ IVDEP DO 140 I=3,IDO,2 IDIJ = IDIJ+2 C1(I-1,K,J) = WA(IDIJ-1)*CH(I-1,K,J)-WA(IDIJ)*CH(I,K,J) C1(I,K,J) = WA(IDIJ-1)*CH(I,K,J)+WA(IDIJ)*CH(I-1,K,J) 140 CONTINUE 141 CONTINUE 142 CONTINUE 143 RETURN END