!CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
!                                                                       
!   FFTPACK 5.0                                                         
!   Copyright (C) 1995-2004, Scientific Computing Division,             
!   University Corporation for Atmospheric Research                     
!   Licensed under the GNU General Public License (GPL)                 
!                                                                       
!   Authors:  Paul N. Swarztrauber and Richard A. Valent                
!                                                                       
!   $Id: r1f2kb.f,v 1.2 2004/06/15 21:29:20 rodney Exp $                
!                                                                       
!CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
                                                                        
      SUBROUTINE R1F2KB (IDO,L1,CC,IN1,CH,IN2,WA1) 
      REAL       CC(IN1,IDO,2,L1), CH(IN2,IDO,L1,2), WA1(IDO) 
!                                                                       
      DO 101 K=1,L1 
         CH(1,1,K,1) = CC(1,1,1,K)+CC(1,IDO,2,K) 
         CH(1,1,K,2) = CC(1,1,1,K)-CC(1,IDO,2,K) 
  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 
                                                                        
            CH(1,I-1,K,1) = CC(1,I-1,1,K)+CC(1,IC-1,2,K) 
            CH(1,I,K,1) = CC(1,I,1,K)-CC(1,IC,2,K) 
                                                                        
            CH(1,I-1,K,2) = WA1(I-2)*(CC(1,I-1,1,K)-CC(1,IC-1,2,K))     &
     &           -WA1(I-1)*(CC(1,I,1,K)+CC(1,IC,2,K))                   
            CH(1,I,K,2) = WA1(I-2)*(CC(1,I,1,K)+CC(1,IC,2,K))+WA1(I-1)  &
     &           *(CC(1,I-1,1,K)-CC(1,IC-1,2,K))                        
                                                                        
  103    CONTINUE 
  104 END DO 
      IF (MOD(IDO,2) .EQ. 1) RETURN 
  105 DO 106 K=1,L1 
         CH(1,IDO,K,1) = CC(1,IDO,1,K)+CC(1,IDO,1,K) 
         CH(1,IDO,K,2) = -(CC(1,1,2,K)+CC(1,1,2,K)) 
  106 END DO 
  107 RETURN 
      END