!CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
!                                                                       
!   FFTPACK 5.0                                                         
!                                                                       
!   Authors:  Paul N. Swarztrauber and Richard A. Valent                
!                                                                       
!   $Id: r1f3kb.f,v 1.2 2004/06/15 21:29:20 rodney Exp $                
!                                                                       
!CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
                                                                        
      SUBROUTINE R1F3KB (IDO,L1,CC,IN1,CH,IN2,WA1,WA2) 
      REAL       CC(IN1,IDO,3,L1)    ,CH(IN2,IDO,L1,3),                 &
     &           WA1(IDO)   ,WA2(IDO)                                   
!                                                                       
      ARG=2.*4.*ATAN(1.0)/3. 
      TAUR=COS(ARG) 
      TAUI=SIN(ARG) 
      DO 101 K=1,L1 
         CH(1,1,K,1) = CC(1,1,1,K)+2.*CC(1,IDO,2,K) 
         CH(1,1,K,2) = CC(1,1,1,K)+(2.*TAUR)*CC(1,IDO,2,K)              &
     &   -(2.*TAUI)*CC(1,1,3,K)                                         
         CH(1,1,K,3) = CC(1,1,1,K)+(2.*TAUR)*CC(1,IDO,2,K)              &
     &   +2.*TAUI*CC(1,1,3,K)                                           
  101 END DO 
      IF (IDO .EQ. 1) RETURN 
      IDP2 = IDO+2 
      DO 103 K=1,L1 
         DO 102 I=3,IDO,2 
            IC = IDP2-I 
        CH(1,I-1,K,1) = CC(1,I-1,1,K)+(CC(1,I-1,3,K)+CC(1,IC-1,2,K)) 
        CH(1,I,K,1) = CC(1,I,1,K)+(CC(1,I,3,K)-CC(1,IC,2,K)) 
        CH(1,I-1,K,2) = WA1(I-2)*                                       &
     & ((CC(1,I-1,1,K)+TAUR*(CC(1,I-1,3,K)+CC(1,IC-1,2,K)))-            &
     & (TAUI*(CC(1,I,3,K)+CC(1,IC,2,K))))                               &
     &                   -WA1(I-1)*                                     &
     & ((CC(1,I,1,K)+TAUR*(CC(1,I,3,K)-CC(1,IC,2,K)))+                  &
     & (TAUI*(CC(1,I-1,3,K)-CC(1,IC-1,2,K))))                           
            CH(1,I,K,2) = WA1(I-2)*                                     &
     & ((CC(1,I,1,K)+TAUR*(CC(1,I,3,K)-CC(1,IC,2,K)))+                  &
     & (TAUI*(CC(1,I-1,3,K)-CC(1,IC-1,2,K))))                           &
     &                  +WA1(I-1)*                                      &
     & ((CC(1,I-1,1,K)+TAUR*(CC(1,I-1,3,K)+CC(1,IC-1,2,K)))-            &
     & (TAUI*(CC(1,I,3,K)+CC(1,IC,2,K))))                               
              CH(1,I-1,K,3) = WA2(I-2)*                                 &
     & ((CC(1,I-1,1,K)+TAUR*(CC(1,I-1,3,K)+CC(1,IC-1,2,K)))+            &
     & (TAUI*(CC(1,I,3,K)+CC(1,IC,2,K))))                               &
     &   -WA2(I-1)*                                                     &
     & ((CC(1,I,1,K)+TAUR*(CC(1,I,3,K)-CC(1,IC,2,K)))-                  &
     & (TAUI*(CC(1,I-1,3,K)-CC(1,IC-1,2,K))))                           
            CH(1,I,K,3) = WA2(I-2)*                                     &
     & ((CC(1,I,1,K)+TAUR*(CC(1,I,3,K)-CC(1,IC,2,K)))-                  &
     & (TAUI*(CC(1,I-1,3,K)-CC(1,IC-1,2,K))))                           &
     &                 +WA2(I-1)*                                       &
     & ((CC(1,I-1,1,K)+TAUR*(CC(1,I-1,3,K)+CC(1,IC-1,2,K)))+            &
     & (TAUI*(CC(1,I,3,K)+CC(1,IC,2,K))))                               
  102    CONTINUE 
  103 END DO 
      RETURN 
      END