*DECK RADF2 SUBROUTINE RADF2 (IDO, L1, CC, CH, WA1) C***BEGIN PROLOGUE RADF2 C***SUBSIDIARY C***PURPOSE Calculate the fast Fourier transform of subvectors of C length two. C***LIBRARY SLATEC (FFTPACK) C***TYPE SINGLE PRECISION (RADF2-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 changing dummy array size declarations (1) to (*). C 881128 Modified by Dick Valent to meet prologue standards. 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 RADF2 DIMENSION CH(IDO,2,*), CC(IDO,L1,2), WA1(*) C***FIRST EXECUTABLE STATEMENT RADF2 DO 101 K=1,L1 CH(1,1,K) = CC(1,K,1)+CC(1,K,2) CH(IDO,2,K) = CC(1,K,1)-CC(1,K,2) 101 CONTINUE IF (IDO-2) 107,105,102 102 IDP2 = IDO+2 IF((IDO-1)/2.LT.L1) GO TO 108 DO 104 K=1,L1 CDIR$ IVDEP DO 103 I=3,IDO,2 IC = IDP2-I TR2 = WA1(I-2)*CC(I-1,K,2)+WA1(I-1)*CC(I,K,2) TI2 = WA1(I-2)*CC(I,K,2)-WA1(I-1)*CC(I-1,K,2) CH(I,1,K) = CC(I,K,1)+TI2 CH(IC,2,K) = TI2-CC(I,K,1) CH(I-1,1,K) = CC(I-1,K,1)+TR2 CH(IC-1,2,K) = CC(I-1,K,1)-TR2 103 CONTINUE 104 CONTINUE GO TO 111 108 DO 110 I=3,IDO,2 IC = IDP2-I CDIR$ IVDEP DO 109 K=1,L1 TR2 = WA1(I-2)*CC(I-1,K,2)+WA1(I-1)*CC(I,K,2) TI2 = WA1(I-2)*CC(I,K,2)-WA1(I-1)*CC(I-1,K,2) CH(I,1,K) = CC(I,K,1)+TI2 CH(IC,2,K) = TI2-CC(I,K,1) CH(I-1,1,K) = CC(I-1,K,1)+TR2 CH(IC-1,2,K) = CC(I-1,K,1)-TR2 109 CONTINUE 110 CONTINUE 111 IF (MOD(IDO,2) .EQ. 1) RETURN 105 DO 106 K=1,L1 CH(1,2,K) = -CC(IDO,K,2) CH(IDO,1,K) = CC(IDO,K,1) 106 CONTINUE 107 RETURN END