SUBROUTINE VRADB4 (MP,IDO,L1,CC,CH,MDIMC,WA1,WA2,WA3)
C
C     VRFFTPK, VERSION 1, AUGUST 1985
C
      DIMENSION  CC(MDIMC,IDO,4,L1)  ,CH(MDIMC,IDO,L1,4)    ,
     1                WA1(IDO)  ,WA2(IDO)  ,WA3(IDO)
      SQRT2=SQRT(2.)
      DO 101 K=1,L1
          DO 1001 M=1,MP
         CH(M,1,K,3) = (CC(M,1,1,K)+CC(M,IDO,4,K))
     1   -(CC(M,IDO,2,K)+CC(M,IDO,2,K))
         CH(M,1,K,1) = (CC(M,1,1,K)+CC(M,IDO,4,K))
     1   +(CC(M,IDO,2,K)+CC(M,IDO,2,K))
         CH(M,1,K,4) = (CC(M,1,1,K)-CC(M,IDO,4,K))
     1   +(CC(M,1,3,K)+CC(M,1,3,K))
         CH(M,1,K,2) = (CC(M,1,1,K)-CC(M,IDO,4,K))
     1   -(CC(M,1,3,K)+CC(M,1,3,K))
 1001     CONTINUE
  101 CONTINUE
      IF (IDO-2) 107,105,102
  102 IDP2 = IDO+2
      DO 104 K=1,L1
         DO 103 I=3,IDO,2
            IC = IDP2-I
               DO 1002 M=1,MP
            CH(M,I-1,K,1) = (CC(M,I-1,1,K)+CC(M,IC-1,4,K))
     1      +(CC(M,I-1,3,K)+CC(M,IC-1,2,K))
            CH(M,I,K,1) = (CC(M,I,1,K)-CC(M,IC,4,K))
     1      +(CC(M,I,3,K)-CC(M,IC,2,K))
            CH(M,I-1,K,2)=WA1(I-2)*((CC(M,I-1,1,K)-CC(M,IC-1,4,K))
     1      -(CC(M,I,3,K)+CC(M,IC,2,K)))-WA1(I-1)
     1      *((CC(M,I,1,K)+CC(M,IC,4,K))+(CC(M,I-1,3,K)-CC(M,IC-1,2,K)))
            CH(M,I,K,2)=WA1(I-2)*((CC(M,I,1,K)+CC(M,IC,4,K))
     1      +(CC(M,I-1,3,K)-CC(M,IC-1,2,K)))+WA1(I-1)
     1      *((CC(M,I-1,1,K)-CC(M,IC-1,4,K))-(CC(M,I,3,K)+CC(M,IC,2,K)))
            CH(M,I-1,K,3)=WA2(I-2)*((CC(M,I-1,1,K)+CC(M,IC-1,4,K))
     1      -(CC(M,I-1,3,K)+CC(M,IC-1,2,K)))-WA2(I-1)
     1      *((CC(M,I,1,K)-CC(M,IC,4,K))-(CC(M,I,3,K)-CC(M,IC,2,K)))
            CH(M,I,K,3)=WA2(I-2)*((CC(M,I,1,K)-CC(M,IC,4,K))
     1      -(CC(M,I,3,K)-CC(M,IC,2,K)))+WA2(I-1)
     1      *((CC(M,I-1,1,K)+CC(M,IC-1,4,K))-(CC(M,I-1,3,K)
     1      +CC(M,IC-1,2,K)))
            CH(M,I-1,K,4)=WA3(I-2)*((CC(M,I-1,1,K)-CC(M,IC-1,4,K))
     1      +(CC(M,I,3,K)+CC(M,IC,2,K)))-WA3(I-1)
     1     *((CC(M,I,1,K)+CC(M,IC,4,K))-(CC(M,I-1,3,K)-CC(M,IC-1,2,K)))
            CH(M,I,K,4)=WA3(I-2)*((CC(M,I,1,K)+CC(M,IC,4,K))
     1      -(CC(M,I-1,3,K)-CC(M,IC-1,2,K)))+WA3(I-1)
     1      *((CC(M,I-1,1,K)-CC(M,IC-1,4,K))+(CC(M,I,3,K)+CC(M,IC,2,K)))
 1002          CONTINUE
  103    CONTINUE
  104 CONTINUE
      IF (MOD(IDO,2) .EQ. 1) RETURN
  105 CONTINUE
      DO 106 K=1,L1
               DO 1003 M=1,MP
         CH(M,IDO,K,1) = (CC(M,IDO,1,K)+CC(M,IDO,3,K))
     1   +(CC(M,IDO,1,K)+CC(M,IDO,3,K))
         CH(M,IDO,K,2) = SQRT2*((CC(M,IDO,1,K)-CC(M,IDO,3,K))
     1   -(CC(M,1,2,K)+CC(M,1,4,K)))
         CH(M,IDO,K,3) = (CC(M,1,4,K)-CC(M,1,2,K))
     1   +(CC(M,1,4,K)-CC(M,1,2,K))
         CH(M,IDO,K,4) = -SQRT2*((CC(M,IDO,1,K)-CC(M,IDO,3,K))
     1   +(CC(M,1,2,K)+CC(M,1,4,K)))
 1003          CONTINUE
  106 CONTINUE
  107 RETURN
      END

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