!CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
!
! FFTPACK 5.0
!
! Authors: Paul N. Swarztrauber and Richard A. Valent
!
! $Id: c1f4kf.f,v 1.2 2004/06/15 21:08:32 rodney Exp $
!
!CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
SUBROUTINE C1F4KF (IDO,L1,NA,CC,IN1,CH,IN2,WA)
REAL CC(IN1,L1,IDO,4),CH(IN2,L1,4,IDO),WA(IDO,3,2)
!
! FFTPACK 5.0 auxiliary routine
!
IF (IDO .GT. 1) GO TO 102
SN = 1./REAL(4*L1)
IF (NA .EQ. 1) GO TO 106
DO 101 K=1,L1
TI1 = CC(2,K,1,1)-CC(2,K,1,3)
TI2 = CC(2,K,1,1)+CC(2,K,1,3)
TR4 = CC(2,K,1,2)-CC(2,K,1,4)
TI3 = CC(2,K,1,2)+CC(2,K,1,4)
TR1 = CC(1,K,1,1)-CC(1,K,1,3)
TR2 = CC(1,K,1,1)+CC(1,K,1,3)
TI4 = CC(1,K,1,4)-CC(1,K,1,2)
TR3 = CC(1,K,1,2)+CC(1,K,1,4)
CC(1,K,1,1) = SN*(TR2+TR3)
CC(1,K,1,3) = SN*(TR2-TR3)
CC(2,K,1,1) = SN*(TI2+TI3)
CC(2,K,1,3) = SN*(TI2-TI3)
CC(1,K,1,2) = SN*(TR1+TR4)
CC(1,K,1,4) = SN*(TR1-TR4)
CC(2,K,1,2) = SN*(TI1+TI4)
CC(2,K,1,4) = SN*(TI1-TI4)
101 END DO
RETURN
106 DO 107 K=1,L1
TI1 = CC(2,K,1,1)-CC(2,K,1,3)
TI2 = CC(2,K,1,1)+CC(2,K,1,3)
TR4 = CC(2,K,1,2)-CC(2,K,1,4)
TI3 = CC(2,K,1,2)+CC(2,K,1,4)
TR1 = CC(1,K,1,1)-CC(1,K,1,3)
TR2 = CC(1,K,1,1)+CC(1,K,1,3)
TI4 = CC(1,K,1,4)-CC(1,K,1,2)
TR3 = CC(1,K,1,2)+CC(1,K,1,4)
CH(1,K,1,1) = SN*(TR2+TR3)
CH(1,K,3,1) = SN*(TR2-TR3)
CH(2,K,1,1) = SN*(TI2+TI3)
CH(2,K,3,1) = SN*(TI2-TI3)
CH(1,K,2,1) = SN*(TR1+TR4)
CH(1,K,4,1) = SN*(TR1-TR4)
CH(2,K,2,1) = SN*(TI1+TI4)
CH(2,K,4,1) = SN*(TI1-TI4)
107 END DO
RETURN
102 DO 103 K=1,L1
TI1 = CC(2,K,1,1)-CC(2,K,1,3)
TI2 = CC(2,K,1,1)+CC(2,K,1,3)
TR4 = CC(2,K,1,2)-CC(2,K,1,4)
TI3 = CC(2,K,1,2)+CC(2,K,1,4)
TR1 = CC(1,K,1,1)-CC(1,K,1,3)
TR2 = CC(1,K,1,1)+CC(1,K,1,3)
TI4 = CC(1,K,1,4)-CC(1,K,1,2)
TR3 = CC(1,K,1,2)+CC(1,K,1,4)
CH(1,K,1,1) = TR2+TR3
CH(1,K,3,1) = TR2-TR3
CH(2,K,1,1) = TI2+TI3
CH(2,K,3,1) = TI2-TI3
CH(1,K,2,1) = TR1+TR4
CH(1,K,4,1) = TR1-TR4
CH(2,K,2,1) = TI1+TI4
CH(2,K,4,1) = TI1-TI4
103 END DO
DO 105 I=2,IDO
DO 104 K=1,L1
TI1 = CC(2,K,I,1)-CC(2,K,I,3)
TI2 = CC(2,K,I,1)+CC(2,K,I,3)
TI3 = CC(2,K,I,2)+CC(2,K,I,4)
TR4 = CC(2,K,I,2)-CC(2,K,I,4)
TR1 = CC(1,K,I,1)-CC(1,K,I,3)
TR2 = CC(1,K,I,1)+CC(1,K,I,3)
TI4 = CC(1,K,I,4)-CC(1,K,I,2)
TR3 = CC(1,K,I,2)+CC(1,K,I,4)
CH(1,K,1,I) = TR2+TR3
CR3 = TR2-TR3
CH(2,K,1,I) = TI2+TI3
CI3 = TI2-TI3
CR2 = TR1+TR4
CR4 = TR1-TR4
CI2 = TI1+TI4
CI4 = TI1-TI4
CH(1,K,2,I) = WA(I,1,1)*CR2+WA(I,1,2)*CI2
CH(2,K,2,I) = WA(I,1,1)*CI2-WA(I,1,2)*CR2
CH(1,K,3,I) = WA(I,2,1)*CR3+WA(I,2,2)*CI3
CH(2,K,3,I) = WA(I,2,1)*CI3-WA(I,2,2)*CR3
CH(1,K,4,I) = WA(I,3,1)*CR4+WA(I,3,2)*CI4
CH(2,K,4,I) = WA(I,3,1)*CI4-WA(I,3,2)*CR4
104 CONTINUE
105 END DO
RETURN
END