!CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
!
! FFTPACK 5.0
!
! Authors: Paul N. Swarztrauber and Richard A. Valent
!
! $Id: mradf4.f,v 1.2 2004/06/15 21:29:20 rodney Exp $
!
!CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
SUBROUTINE MRADF4 (M,IDO,L1,CC,IM1,IN1,CH,IM2,IN2,WA1,WA2,WA3)
REAL CC(IN1,IDO,L1,4) ,CH(IN2,IDO,4,L1) , &
& WA1(IDO) ,WA2(IDO) ,WA3(IDO)
!
HSQT2=SQRT(2.)/2.
M1D = (M-1)*IM1+1
M2S = 1-IM2
DO 101 K=1,L1
M2 = M2S
DO 1001 M1=1,M1D,IM1
M2 = M2+IM2
CH(M2,1,1,K) = (CC(M1,1,K,2)+CC(M1,1,K,4)) &
& +(CC(M1,1,K,1)+CC(M1,1,K,3))
CH(M2,IDO,4,K) = (CC(M1,1,K,1)+CC(M1,1,K,3)) &
& -(CC(M1,1,K,2)+CC(M1,1,K,4))
CH(M2,IDO,2,K) = CC(M1,1,K,1)-CC(M1,1,K,3)
CH(M2,1,3,K) = CC(M1,1,K,4)-CC(M1,1,K,2)
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 1003 M1=1,M1D,IM1
M2 = M2+IM2
CH(M2,I-1,1,K) = ((WA1(I-2)*CC(M1,I-1,K,2)+WA1(I-1)* &
& CC(M1,I,K,2))+(WA3(I-2)*CC(M1,I-1,K,4)+WA3(I-1)* &
& CC(M1,I,K,4)))+(CC(M1,I-1,K,1)+(WA2(I-2)*CC(M1,I-1,K,3)+ &
& WA2(I-1)*CC(M1,I,K,3)))
CH(M2,IC-1,4,K) = (CC(M1,I-1,K,1)+(WA2(I-2)*CC(M1,I-1,K,3)+ &
& WA2(I-1)*CC(M1,I,K,3)))-((WA1(I-2)*CC(M1,I-1,K,2)+ &
& WA1(I-1)*CC(M1,I,K,2))+(WA3(I-2)*CC(M1,I-1,K,4)+ &
& WA3(I-1)*CC(M1,I,K,4)))
CH(M2,I,1,K) = ((WA1(I-2)*CC(M1,I,K,2)-WA1(I-1)* &
& CC(M1,I-1,K,2))+(WA3(I-2)*CC(M1,I,K,4)-WA3(I-1)* &
& CC(M1,I-1,K,4)))+(CC(M1,I,K,1)+(WA2(I-2)*CC(M1,I,K,3)- &
& WA2(I-1)*CC(M1,I-1,K,3)))
CH(M2,IC,4,K) = ((WA1(I-2)*CC(M1,I,K,2)-WA1(I-1)* &
& CC(M1,I-1,K,2))+(WA3(I-2)*CC(M1,I,K,4)-WA3(I-1)* &
& CC(M1,I-1,K,4)))-(CC(M1,I,K,1)+(WA2(I-2)*CC(M1,I,K,3)- &
& WA2(I-1)*CC(M1,I-1,K,3)))
CH(M2,I-1,3,K) = ((WA1(I-2)*CC(M1,I,K,2)-WA1(I-1)* &
& CC(M1,I-1,K,2))-(WA3(I-2)*CC(M1,I,K,4)-WA3(I-1)* &
& CC(M1,I-1,K,4)))+(CC(M1,I-1,K,1)-(WA2(I-2)*CC(M1,I-1,K,3)+ &
& WA2(I-1)*CC(M1,I,K,3)))
CH(M2,IC-1,2,K) = (CC(M1,I-1,K,1)-(WA2(I-2)*CC(M1,I-1,K,3)+ &
& WA2(I-1)*CC(M1,I,K,3)))-((WA1(I-2)*CC(M1,I,K,2)-WA1(I-1)* &
& CC(M1,I-1,K,2))-(WA3(I-2)*CC(M1,I,K,4)-WA3(I-1)* &
& CC(M1,I-1,K,4)))
CH(M2,I,3,K) = ((WA3(I-2)*CC(M1,I-1,K,4)+WA3(I-1)* &
& CC(M1,I,K,4))-(WA1(I-2)*CC(M1,I-1,K,2)+WA1(I-1)* &
& CC(M1,I,K,2)))+(CC(M1,I,K,1)-(WA2(I-2)*CC(M1,I,K,3)- &
& WA2(I-1)*CC(M1,I-1,K,3)))
CH(M2,IC,2,K) = ((WA3(I-2)*CC(M1,I-1,K,4)+WA3(I-1)* &
& CC(M1,I,K,4))-(WA1(I-2)*CC(M1,I-1,K,2)+WA1(I-1)* &
& CC(M1,I,K,2)))-(CC(M1,I,K,1)-(WA2(I-2)*CC(M1,I,K,3)- &
& WA2(I-1)*CC(M1,I-1,K,3)))
1003 CONTINUE
103 CONTINUE
104 END DO
IF (MOD(IDO,2) .EQ. 1) RETURN
105 CONTINUE
DO 106 K=1,L1
M2 = M2S
DO 1006 M1=1,M1D,IM1
M2 = M2+IM2
CH(M2,IDO,1,K) = (HSQT2*(CC(M1,IDO,K,2)-CC(M1,IDO,K,4)))+ &
& CC(M1,IDO,K,1)
CH(M2,IDO,3,K) = CC(M1,IDO,K,1)-(HSQT2*(CC(M1,IDO,K,2)- &
& CC(M1,IDO,K,4)))
CH(M2,1,2,K) = (-HSQT2*(CC(M1,IDO,K,2)+CC(M1,IDO,K,4)))- &
& CC(M1,IDO,K,3)
CH(M2,1,4,K) = (-HSQT2*(CC(M1,IDO,K,2)+CC(M1,IDO,K,4)))+ &
& CC(M1,IDO,K,3)
1006 CONTINUE
106 END DO
107 RETURN
END