!CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
!
! FFTPACK 5.0
!
! Authors: Paul N. Swarztrauber and Richard A. Valent
!
! $Id: mradb4.f,v 1.2 2004/06/15 21:29:19 rodney Exp $
!
!CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
SUBROUTINE MRADB4 (M,IDO,L1,CC,IM1,IN1,CH,IM2,IN2,WA1,WA2,WA3)
REAL CC(IN1,IDO,4,L1) ,CH(IN2,IDO,L1,4) , &
& WA1(IDO) , WA2(IDO) , WA3(IDO)
!
M1D = (M-1)*IM1+1
M2S = 1-IM2
SQRT2=SQRT(2.)
DO 101 K=1,L1
M2 = M2S
DO 1001 M1=1,M1D,IM1
M2 = M2+IM2
CH(M2,1,K,3) = (CC(M1,1,1,K)+CC(M1,IDO,4,K)) &
& -(CC(M1,IDO,2,K)+CC(M1,IDO,2,K))
CH(M2,1,K,1) = (CC(M1,1,1,K)+CC(M1,IDO,4,K)) &
& +(CC(M1,IDO,2,K)+CC(M1,IDO,2,K))
CH(M2,1,K,4) = (CC(M1,1,1,K)-CC(M1,IDO,4,K)) &
& +(CC(M1,1,3,K)+CC(M1,1,3,K))
CH(M2,1,K,2) = (CC(M1,1,1,K)-CC(M1,IDO,4,K)) &
& -(CC(M1,1,3,K)+CC(M1,1,3,K))
1001 CONTINUE
101 END DO
IF (IDO-2) 107,105,102
102 IDP2 = IDO+2
DO 104 K=1,L1
DO 103 I=3,IDO,2
IC = IDP2-I
M2 = M2S
DO 1002 M1=1,M1D,IM1
M2 = M2+IM2
CH(M2,I-1,K,1) = (CC(M1,I-1,1,K)+CC(M1,IC-1,4,K)) &
& +(CC(M1,I-1,3,K)+CC(M1,IC-1,2,K))
CH(M2,I,K,1) = (CC(M1,I,1,K)-CC(M1,IC,4,K)) &
& +(CC(M1,I,3,K)-CC(M1,IC,2,K))
CH(M2,I-1,K,2)=WA1(I-2)*((CC(M1,I-1,1,K)-CC(M1,IC-1,4,K)) &
& -(CC(M1,I,3,K)+CC(M1,IC,2,K)))-WA1(I-1) &
& *((CC(M1,I,1,K)+CC(M1,IC,4,K))+(CC(M1,I-1,3,K)-CC(M1,IC-1,2,K)))
CH(M2,I,K,2)=WA1(I-2)*((CC(M1,I,1,K)+CC(M1,IC,4,K)) &
& +(CC(M1,I-1,3,K)-CC(M1,IC-1,2,K)))+WA1(I-1) &
& *((CC(M1,I-1,1,K)-CC(M1,IC-1,4,K))-(CC(M1,I,3,K)+CC(M1,IC,2,K)))
CH(M2,I-1,K,3)=WA2(I-2)*((CC(M1,I-1,1,K)+CC(M1,IC-1,4,K)) &
& -(CC(M1,I-1,3,K)+CC(M1,IC-1,2,K)))-WA2(I-1) &
& *((CC(M1,I,1,K)-CC(M1,IC,4,K))-(CC(M1,I,3,K)-CC(M1,IC,2,K)))
CH(M2,I,K,3)=WA2(I-2)*((CC(M1,I,1,K)-CC(M1,IC,4,K)) &
& -(CC(M1,I,3,K)-CC(M1,IC,2,K)))+WA2(I-1) &
& *((CC(M1,I-1,1,K)+CC(M1,IC-1,4,K))-(CC(M1,I-1,3,K) &
& +CC(M1,IC-1,2,K)))
CH(M2,I-1,K,4)=WA3(I-2)*((CC(M1,I-1,1,K)-CC(M1,IC-1,4,K)) &
& +(CC(M1,I,3,K)+CC(M1,IC,2,K)))-WA3(I-1) &
& *((CC(M1,I,1,K)+CC(M1,IC,4,K))-(CC(M1,I-1,3,K)-CC(M1,IC-1,2,K)))
CH(M2,I,K,4)=WA3(I-2)*((CC(M1,I,1,K)+CC(M1,IC,4,K)) &
& -(CC(M1,I-1,3,K)-CC(M1,IC-1,2,K)))+WA3(I-1) &
& *((CC(M1,I-1,1,K)-CC(M1,IC-1,4,K))+(CC(M1,I,3,K)+CC(M1,IC,2,K)))
1002 CONTINUE
103 CONTINUE
104 END DO
IF (MOD(IDO,2) .EQ. 1) RETURN
105 CONTINUE
DO 106 K=1,L1
M2 = M2S
DO 1003 M1=1,M1D,IM1
M2 = M2+IM2
CH(M2,IDO,K,1) = (CC(M1,IDO,1,K)+CC(M1,IDO,3,K)) &
& +(CC(M1,IDO,1,K)+CC(M1,IDO,3,K))
CH(M2,IDO,K,2) = SQRT2*((CC(M1,IDO,1,K)-CC(M1,IDO,3,K)) &
& -(CC(M1,1,2,K)+CC(M1,1,4,K)))
CH(M2,IDO,K,3) = (CC(M1,1,4,K)-CC(M1,1,2,K)) &
& +(CC(M1,1,4,K)-CC(M1,1,2,K))
CH(M2,IDO,K,4) = -SQRT2*((CC(M1,IDO,1,K)-CC(M1,IDO,3,K)) &
& +(CC(M1,1,2,K)+CC(M1,1,4,K)))
1003 CONTINUE
106 END DO
107 RETURN
END