SUBROUTINE EZFFTB(N,R,AZERO,A,B,WSAVE) C***BEGIN PROLOGUE EZFFTB C***DATE WRITTEN 790601 (YYMMDD) C***REVISION DATE 860115 (YYMMDD) C***CATEGORY NO. J1A1 C***KEYWORDS FOURIER TRANSFORM C***AUTHOR SWARZTRAUBER, P. N., (NCAR) C***PURPOSE A Simplified real, periodic, backward transform C***DESCRIPTION C From the book, "Numerical Methods and Software" by C D. Kahaner, C. Moler, S. Nash C Prentice Hall, 1988 C C Subroutine EZFFTB computes a real perodic sequence from its C Fourier coefficients (Fourier synthesis). The transform is C defined below at Output Parameter R. EZFFTB is a simplified C but slower version of RFFTB. C C Input Parameters C C N the length of the output array R. The method is most C efficient when N is the product of small primes. C C AZERO the constant Fourier coefficient C C A,B arrays which contain the remaining Fourier coefficients. C These arrays are not destroyed. C C The length of these arrays depends on whether N is even or C odd. C C If N is even, N/2 locations are required. C If N is odd, (N-1)/2 locations are required C C WSAVE a work array which must be dimensioned at least 3*N+15 C in the program that calls EZFFTB. The WSAVE array must be C initialized by calling subroutine EZFFTI(N,WSAVE), and a C different WSAVE array must be used for each different C value of N. This initialization does not have to be C repeated so long as N remains unchanged. Thus subsequent C transforms can be obtained faster than the first. C The same WSAVE array can be used by EZFFTF and EZFFTB. C C C Output Parameters C C R if N is even, define KMAX=N/2 C if N is odd, define KMAX=(N-1)/2 C C Then for I=1,...,N C C R(I)=AZERO plus the sum from K=1 to K=KMAX of C C A(K)*COS(K*(I-1)*2*PI/N)+B(K)*SIN(K*(I-1)*2*PI/N) C C ********************* Complex Notation ************************** C C For J=1,...,N C C R(J) equals the sum from K=-KMAX to K=KMAX of C C C(K)*EXP(I*K*(J-1)*2*PI/N) C C where C C C(K) = .5*CMPLX(A(K),-B(K)) for K=1,...,KMAX C C C(-K) = CONJG(C(K)) C C C(0) = AZERO C C and I=SQRT(-1) C C *************** Amplitude - Phase Notation *********************** C C For I=1,...,N C C R(I) equals AZERO plus the sum from K=1 to K=KMAX of C C ALPHA(K)*COS(K*(I-1)*2*PI/N+BETA(K)) C C where C C ALPHA(K) = SQRT(A(K)*A(K)+B(K)*B(K)) C C COS(BETA(K))=A(K)/ALPHA(K) C C SIN(BETA(K))=-B(K)/ALPHA(K) C C * * C * References * C * * C * 1. P.N. Swarztrauber, Vectorizing the FFTs, in Parallel * C * Computations (G. Rodrigue, ed.), Academic Press, 1982, * C * pp. 51-83. * C * 2. B.L. Buzbee, The SLATEC Common Math Library, in Sources * C * and Development of Mathematical Software (W. Cowell, ed.), * C * Prentice-Hall, 1984, pp. 302-318. * C * * C ********************************************************************* C C***REFERENCES (NONE) C***ROUTINES CALLED RFFTB C***END PROLOGUE EZFFTB DIMENSION R(*) ,A(*) ,B(*) ,WSAVE(*) C***FIRST EXECUTABLE STATEMENT EZFFTB IF (N-2) 101,102,103 101 R(1) = AZERO RETURN 102 R(1) = AZERO+A(1) R(2) = AZERO-A(1) RETURN 103 NS2 = (N-1)/2 DO 104 I=1,NS2 R(2*I) = .5*A(I) R(2*I+1) = -.5*B(I) 104 CONTINUE R(1) = AZERO IF (MOD(N,2) .EQ. 0) R(N) = A(NS2+1) CALL RFFTB (N,R,WSAVE(N+1)) RETURN END SUBROUTINE RFFTB(N,R,WSAVE) C***BEGIN PROLOGUE RFFTB C THIS PROLOGUE HAS BEEN REMOVED FOR REASONS OF SPACE C FOR A COMPLETE COPY OF THIS ROUTINE CONTACT THE AUTHORS C From the book "Numerical Methods and Software" C by D. Kahaner, C. Moler, S. Nash C Prentice Hall 1988 C***END PROLOGUE RFFTB DIMENSION R(*) ,WSAVE(*) C***FIRST EXECUTABLE STATEMENT RFFTB IF (N .EQ. 1) RETURN CALL RFFTB1 (N,R,WSAVE,WSAVE(N+1),WSAVE(2*N+1)) RETURN END SUBROUTINE RFFTB1(N,C,CH,WA,IFAC) C***BEGIN PROLOGUE RFFTB1 C***REFER TO RFFTB C***ROUTINES CALLED RADB2,RADB3,RADB4,RADB5,RADBG C***END PROLOGUE RFFTB1 DIMENSION CH(*) ,C(*) ,WA(*) ,IFAC(*) C***FIRST EXECUTABLE STATEMENT RFFTB1 NF = IFAC(2) NA = 0 L1 = 1 IW = 1 DO 116 K1=1,NF IP = IFAC(K1+2) L2 = IP*L1 IDO = N/L2 IDL1 = IDO*L1 IF (IP .NE. 4) GO TO 103 IX2 = IW+IDO IX3 = IX2+IDO IF (NA .NE. 0) GO TO 101 CALL RADB4 (IDO,L1,C,CH,WA(IW),WA(IX2),WA(IX3)) GO TO 102 101 CALL RADB4 (IDO,L1,CH,C,WA(IW),WA(IX2),WA(IX3)) 102 NA = 1-NA GO TO 115 103 IF (IP .NE. 2) GO TO 106 IF (NA .NE. 0) GO TO 104 CALL RADB2 (IDO,L1,C,CH,WA(IW)) GO TO 105 104 CALL RADB2 (IDO,L1,CH,C,WA(IW)) 105 NA = 1-NA GO TO 115 106 IF (IP .NE. 3) GO TO 109 IX2 = IW+IDO IF (NA .NE. 0) GO TO 107 CALL RADB3 (IDO,L1,C,CH,WA(IW),WA(IX2)) GO TO 108 107 CALL RADB3 (IDO,L1,CH,C,WA(IW),WA(IX2)) 108 NA = 1-NA GO TO 115 109 IF (IP .NE. 5) GO TO 112 IX2 = IW+IDO IX3 = IX2+IDO IX4 = IX3+IDO IF (NA .NE. 0) GO TO 110 CALL RADB5 (IDO,L1,C,CH,WA(IW),WA(IX2),WA(IX3),WA(IX4)) GO TO 111 110 CALL RADB5 (IDO,L1,CH,C,WA(IW),WA(IX2),WA(IX3),WA(IX4)) 111 NA = 1-NA GO TO 115 112 IF (NA .NE. 0) GO TO 113 CALL RADBG (IDO,IP,L1,IDL1,C,C,C,CH,CH,WA(IW)) GO TO 114 113 CALL RADBG (IDO,IP,L1,IDL1,CH,CH,CH,C,C,WA(IW)) 114 IF (IDO .EQ. 1) NA = 1-NA 115 L1 = L2 IW = IW+(IP-1)*IDO 116 CONTINUE IF (NA .EQ. 0) RETURN DO 117 I=1,N C(I) = CH(I) 117 CONTINUE RETURN END SUBROUTINE RADB2(IDO,L1,CC,CH,WA1) C***BEGIN PROLOGUE RADB2 C***REFER TO RFFTB C***ROUTINES CALLED (NONE) C***END PROLOGUE RADB2 DIMENSION CC(IDO,2,L1) ,CH(IDO,L1,2) , 1 WA1(*) C***FIRST EXECUTABLE STATEMENT RADB2 DO 101 K=1,L1 CH(1,K,1) = CC(1,1,K)+CC(IDO,2,K) CH(1,K,2) = CC(1,1,K)-CC(IDO,2,K) 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 CH(I-1,K,1) = CC(I-1,1,K)+CC(IC-1,2,K) TR2 = CC(I-1,1,K)-CC(IC-1,2,K) CH(I,K,1) = CC(I,1,K)-CC(IC,2,K) TI2 = CC(I,1,K)+CC(IC,2,K) CH(I-1,K,2) = WA1(I-2)*TR2-WA1(I-1)*TI2 CH(I,K,2) = WA1(I-2)*TI2+WA1(I-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 CH(I-1,K,1) = CC(I-1,1,K)+CC(IC-1,2,K) TR2 = CC(I-1,1,K)-CC(IC-1,2,K) CH(I,K,1) = CC(I,1,K)-CC(IC,2,K) TI2 = CC(I,1,K)+CC(IC,2,K) CH(I-1,K,2) = WA1(I-2)*TR2-WA1(I-1)*TI2 CH(I,K,2) = WA1(I-2)*TI2+WA1(I-1)*TR2 109 CONTINUE 110 CONTINUE 111 IF (MOD(IDO,2) .EQ. 1) RETURN 105 DO 106 K=1,L1 CH(IDO,K,1) = CC(IDO,1,K)+CC(IDO,1,K) CH(IDO,K,2) = -(CC(1,2,K)+CC(1,2,K)) 106 CONTINUE 107 RETURN END SUBROUTINE RADB3(IDO,L1,CC,CH,WA1,WA2) C***BEGIN PROLOGUE RADB3 C***REFER TO RFFTB C***ROUTINES CALLED (NONE) C***END PROLOGUE RADB3 DIMENSION CC(IDO,3,L1) ,CH(IDO,L1,3) , 1 WA1(*) ,WA2(*) C***FIRST EXECUTABLE STATEMENT RADB3 TAUR = -.5 TAUI = .5*SQRT(3.) DO 101 K=1,L1 TR2 = CC(IDO,2,K)+CC(IDO,2,K) CR2 = CC(1,1,K)+TAUR*TR2 CH(1,K,1) = CC(1,1,K)+TR2 CI3 = TAUI*(CC(1,3,K)+CC(1,3,K)) CH(1,K,2) = CR2-CI3 CH(1,K,3) = CR2+CI3 101 CONTINUE IF (IDO .EQ. 1) RETURN IDP2 = IDO+2 IF((IDO-1)/2.LT.L1) GO TO 104 DO 103 K=1,L1 CDIR$ IVDEP DO 102 I=3,IDO,2 IC = IDP2-I TR2 = CC(I-1,3,K)+CC(IC-1,2,K) CR2 = CC(I-1,1,K)+TAUR*TR2 CH(I-1,K,1) = CC(I-1,1,K)+TR2 TI2 = CC(I,3,K)-CC(IC,2,K) CI2 = CC(I,1,K)+TAUR*TI2 CH(I,K,1) = CC(I,1,K)+TI2 CR3 = TAUI*(CC(I-1,3,K)-CC(IC-1,2,K)) CI3 = TAUI*(CC(I,3,K)+CC(IC,2,K)) DR2 = CR2-CI3 DR3 = CR2+CI3 DI2 = CI2+CR3 DI3 = CI2-CR3 CH(I-1,K,2) = WA1(I-2)*DR2-WA1(I-1)*DI2 CH(I,K,2) = WA1(I-2)*DI2+WA1(I-1)*DR2 CH(I-1,K,3) = WA2(I-2)*DR3-WA2(I-1)*DI3 CH(I,K,3) = WA2(I-2)*DI3+WA2(I-1)*DR3 102 CONTINUE 103 CONTINUE RETURN 104 DO 106 I=3,IDO,2 IC = IDP2-I CDIR$ IVDEP DO 105 K=1,L1 TR2 = CC(I-1,3,K)+CC(IC-1,2,K) CR2 = CC(I-1,1,K)+TAUR*TR2 CH(I-1,K,1) = CC(I-1,1,K)+TR2 TI2 = CC(I,3,K)-CC(IC,2,K) CI2 = CC(I,1,K)+TAUR*TI2 CH(I,K,1) = CC(I,1,K)+TI2 CR3 = TAUI*(CC(I-1,3,K)-CC(IC-1,2,K)) CI3 = TAUI*(CC(I,3,K)+CC(IC,2,K)) DR2 = CR2-CI3 DR3 = CR2+CI3 DI2 = CI2+CR3 DI3 = CI2-CR3 CH(I-1,K,2) = WA1(I-2)*DR2-WA1(I-1)*DI2 CH(I,K,2) = WA1(I-2)*DI2+WA1(I-1)*DR2 CH(I-1,K,3) = WA2(I-2)*DR3-WA2(I-1)*DI3 CH(I,K,3) = WA2(I-2)*DI3+WA2(I-1)*DR3 105 CONTINUE 106 CONTINUE RETURN END SUBROUTINE RADB4(IDO,L1,CC,CH,WA1,WA2,WA3) C***BEGIN PROLOGUE RADB4 C***REFER TO RFFTB C***ROUTINES CALLED (NONE) C***END PROLOGUE RADB4 DIMENSION CC(IDO,4,L1) ,CH(IDO,L1,4) , 1 WA1(*) ,WA2(*) ,WA3(*) C***FIRST EXECUTABLE STATEMENT RADB4 SQRT2 = SQRT(2.) DO 101 K=1,L1 TR1 = CC(1,1,K)-CC(IDO,4,K) TR2 = CC(1,1,K)+CC(IDO,4,K) TR3 = CC(IDO,2,K)+CC(IDO,2,K) TR4 = CC(1,3,K)+CC(1,3,K) CH(1,K,1) = TR2+TR3 CH(1,K,2) = TR1-TR4 CH(1,K,3) = TR2-TR3 CH(1,K,4) = TR1+TR4 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 TI1 = CC(I,1,K)+CC(IC,4,K) TI2 = CC(I,1,K)-CC(IC,4,K) TI3 = CC(I,3,K)-CC(IC,2,K) TR4 = CC(I,3,K)+CC(IC,2,K) TR1 = CC(I-1,1,K)-CC(IC-1,4,K) TR2 = CC(I-1,1,K)+CC(IC-1,4,K) TI4 = CC(I-1,3,K)-CC(IC-1,2,K) TR3 = CC(I-1,3,K)+CC(IC-1,2,K) CH(I-1,K,1) = TR2+TR3 CR3 = TR2-TR3 CH(I,K,1) = TI2+TI3 CI3 = TI2-TI3 CR2 = TR1-TR4 CR4 = TR1+TR4 CI2 = TI1+TI4 CI4 = TI1-TI4 CH(I-1,K,2) = WA1(I-2)*CR2-WA1(I-1)*CI2 CH(I,K,2) = WA1(I-2)*CI2+WA1(I-1)*CR2 CH(I-1,K,3) = WA2(I-2)*CR3-WA2(I-1)*CI3 CH(I,K,3) = WA2(I-2)*CI3+WA2(I-1)*CR3 CH(I-1,K,4) = WA3(I-2)*CR4-WA3(I-1)*CI4 CH(I,K,4) = WA3(I-2)*CI4+WA3(I-1)*CR4 103 CONTINUE 104 CONTINUE GO TO 111 108 DO 110 I=3,IDO,2 IC = IDP2-I CDIR$ IVDEP DO 109 K=1,L1 TI1 = CC(I,1,K)+CC(IC,4,K) TI2 = CC(I,1,K)-CC(IC,4,K) TI3 = CC(I,3,K)-CC(IC,2,K) TR4 = CC(I,3,K)+CC(IC,2,K) TR1 = CC(I-1,1,K)-CC(IC-1,4,K) TR2 = CC(I-1,1,K)+CC(IC-1,4,K) TI4 = CC(I-1,3,K)-CC(IC-1,2,K) TR3 = CC(I-1,3,K)+CC(IC-1,2,K) CH(I-1,K,1) = TR2+TR3 CR3 = TR2-TR3 CH(I,K,1) = TI2+TI3 CI3 = TI2-TI3 CR2 = TR1-TR4 CR4 = TR1+TR4 CI2 = TI1+TI4 CI4 = TI1-TI4 CH(I-1,K,2) = WA1(I-2)*CR2-WA1(I-1)*CI2 CH(I,K,2) = WA1(I-2)*CI2+WA1(I-1)*CR2 CH(I-1,K,3) = WA2(I-2)*CR3-WA2(I-1)*CI3 CH(I,K,3) = WA2(I-2)*CI3+WA2(I-1)*CR3 CH(I-1,K,4) = WA3(I-2)*CR4-WA3(I-1)*CI4 CH(I,K,4) = WA3(I-2)*CI4+WA3(I-1)*CR4 109 CONTINUE 110 CONTINUE 111 IF (MOD(IDO,2) .EQ. 1) RETURN 105 DO 106 K=1,L1 TI1 = CC(1,2,K)+CC(1,4,K) TI2 = CC(1,4,K)-CC(1,2,K) TR1 = CC(IDO,1,K)-CC(IDO,3,K) TR2 = CC(IDO,1,K)+CC(IDO,3,K) CH(IDO,K,1) = TR2+TR2 CH(IDO,K,2) = SQRT2*(TR1-TI1) CH(IDO,K,3) = TI2+TI2 CH(IDO,K,4) = -SQRT2*(TR1+TI1) 106 CONTINUE 107 RETURN END SUBROUTINE RADB5(IDO,L1,CC,CH,WA1,WA2,WA3,WA4) C***BEGIN PROLOGUE RADB5 C***REFER TO RFFTB C***ROUTINES CALLED (NONE) C***END PROLOGUE RADB5 DIMENSION CC(IDO,5,L1) ,CH(IDO,L1,5) , 1 WA1(*) ,WA2(*) ,WA3(*) ,WA4(*) C***FIRST EXECUTABLE STATEMENT RADB5 PI = 4.*ATAN(1.) TR11 = SIN(.1*PI) TI11 = SIN(.4*PI) TR12 = -SIN(.3*PI) TI12 = SIN(.2*PI) DO 101 K=1,L1 TI5 = CC(1,3,K)+CC(1,3,K) TI4 = CC(1,5,K)+CC(1,5,K) TR2 = CC(IDO,2,K)+CC(IDO,2,K) TR3 = CC(IDO,4,K)+CC(IDO,4,K) CH(1,K,1) = CC(1,1,K)+TR2+TR3 CR2 = CC(1,1,K)+TR11*TR2+TR12*TR3 CR3 = CC(1,1,K)+TR12*TR2+TR11*TR3 CI5 = TI11*TI5+TI12*TI4 CI4 = TI12*TI5-TI11*TI4 CH(1,K,2) = CR2-CI5 CH(1,K,3) = CR3-CI4 CH(1,K,4) = CR3+CI4 CH(1,K,5) = CR2+CI5 101 CONTINUE IF (IDO .EQ. 1) RETURN IDP2 = IDO+2 IF((IDO-1)/2.LT.L1) GO TO 104 DO 103 K=1,L1 CDIR$ IVDEP DO 102 I=3,IDO,2 IC = IDP2-I TI5 = CC(I,3,K)+CC(IC,2,K) TI2 = CC(I,3,K)-CC(IC,2,K) TI4 = CC(I,5,K)+CC(IC,4,K) TI3 = CC(I,5,K)-CC(IC,4,K) TR5 = CC(I-1,3,K)-CC(IC-1,2,K) TR2 = CC(I-1,3,K)+CC(IC-1,2,K) TR4 = CC(I-1,5,K)-CC(IC-1,4,K) TR3 = CC(I-1,5,K)+CC(IC-1,4,K) CH(I-1,K,1) = CC(I-1,1,K)+TR2+TR3 CH(I,K,1) = CC(I,1,K)+TI2+TI3 CR2 = CC(I-1,1,K)+TR11*TR2+TR12*TR3 CI2 = CC(I,1,K)+TR11*TI2+TR12*TI3 CR3 = CC(I-1,1,K)+TR12*TR2+TR11*TR3 CI3 = CC(I,1,K)+TR12*TI2+TR11*TI3 CR5 = TI11*TR5+TI12*TR4 CI5 = TI11*TI5+TI12*TI4 CR4 = TI12*TR5-TI11*TR4 CI4 = TI12*TI5-TI11*TI4 DR3 = CR3-CI4 DR4 = CR3+CI4 DI3 = CI3+CR4 DI4 = CI3-CR4 DR5 = CR2+CI5 DR2 = CR2-CI5 DI5 = CI2-CR5 DI2 = CI2+CR5 CH(I-1,K,2) = WA1(I-2)*DR2-WA1(I-1)*DI2 CH(I,K,2) = WA1(I-2)*DI2+WA1(I-1)*DR2 CH(I-1,K,3) = WA2(I-2)*DR3-WA2(I-1)*DI3 CH(I,K,3) = WA2(I-2)*DI3+WA2(I-1)*DR3 CH(I-1,K,4) = WA3(I-2)*DR4-WA3(I-1)*DI4 CH(I,K,4) = WA3(I-2)*DI4+WA3(I-1)*DR4 CH(I-1,K,5) = WA4(I-2)*DR5-WA4(I-1)*DI5 CH(I,K,5) = WA4(I-2)*DI5+WA4(I-1)*DR5 102 CONTINUE 103 CONTINUE RETURN 104 DO 106 I=3,IDO,2 IC = IDP2-I CDIR$ IVDEP DO 105 K=1,L1 TI5 = CC(I,3,K)+CC(IC,2,K) TI2 = CC(I,3,K)-CC(IC,2,K) TI4 = CC(I,5,K)+CC(IC,4,K) TI3 = CC(I,5,K)-CC(IC,4,K) TR5 = CC(I-1,3,K)-CC(IC-1,2,K) TR2 = CC(I-1,3,K)+CC(IC-1,2,K) TR4 = CC(I-1,5,K)-CC(IC-1,4,K) TR3 = CC(I-1,5,K)+CC(IC-1,4,K) CH(I-1,K,1) = CC(I-1,1,K)+TR2+TR3 CH(I,K,1) = CC(I,1,K)+TI2+TI3 CR2 = CC(I-1,1,K)+TR11*TR2+TR12*TR3 CI2 = CC(I,1,K)+TR11*TI2+TR12*TI3 CR3 = CC(I-1,1,K)+TR12*TR2+TR11*TR3 CI3 = CC(I,1,K)+TR12*TI2+TR11*TI3 CR5 = TI11*TR5+TI12*TR4 CI5 = TI11*TI5+TI12*TI4 CR4 = TI12*TR5-TI11*TR4 CI4 = TI12*TI5-TI11*TI4 DR3 = CR3-CI4 DR4 = CR3+CI4 DI3 = CI3+CR4 DI4 = CI3-CR4 DR5 = CR2+CI5 DR2 = CR2-CI5 DI5 = CI2-CR5 DI2 = CI2+CR5 CH(I-1,K,2) = WA1(I-2)*DR2-WA1(I-1)*DI2 CH(I,K,2) = WA1(I-2)*DI2+WA1(I-1)*DR2 CH(I-1,K,3) = WA2(I-2)*DR3-WA2(I-1)*DI3 CH(I,K,3) = WA2(I-2)*DI3+WA2(I-1)*DR3 CH(I-1,K,4) = WA3(I-2)*DR4-WA3(I-1)*DI4 CH(I,K,4) = WA3(I-2)*DI4+WA3(I-1)*DR4 CH(I-1,K,5) = WA4(I-2)*DR5-WA4(I-1)*DI5 CH(I,K,5) = WA4(I-2)*DI5+WA4(I-1)*DR5 105 CONTINUE 106 CONTINUE RETURN END SUBROUTINE RADBG(IDO,IP,L1,IDL1,CC,C1,C2,CH,CH2,WA) C***BEGIN PROLOGUE RADBG C***REFER TO RFFTB C***ROUTINES CALLED (NONE) C***END PROLOGUE RADBG DIMENSION CH(IDO,L1,IP) ,CC(IDO,IP,L1) , 1 C1(IDO,L1,IP) ,C2(IDL1,IP), 2 CH2(IDL1,IP) ,WA(*) C***FIRST EXECUTABLE STATEMENT RADBG TPI = 8.*ATAN(1.) ARG = TPI/REAL(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