C DRUCO1    SOURCE    CHAT      05/01/12    22:55:14     5004
C DRUCO1    SOURCE    JFG        02/07/04
      SUBROUTINE DRUCO1(S1,DF,BETINSA)
C
      IMPLICIT INTEGER(I-N)
      IMPLICIT REAL*8(A-H,O-Z)
      DIMENSION S1(6),DF(6)
C
      SEGMENT BETINSA
       REAL*8 RT,RC,YOUN,XNU,GFT,GFC,CAR
       REAL*8 DKT,DKC,SEQT,SEQC,ENDT,ENDC
       INTEGER IFIS,IPLA,IBB,IGAU1
      ENDSEGMENT
C
      BETA = 1.2D0
      ALC=(BETA-1.)/(2.*BETA-1.)
      BEC=BETA/(2.*BETA-1.)
C
      SX=S1(1)
      SY=S1(2)
      SZ=S1(3)
      SXY=S1(4)
      SXZ=S1(5)
      SYZ=S1(6)
      A = SX-SY
      B = SY-SZ
      C = SX-SZ
      DJ2=(A*A+B*B+C*C+SXY*SXY+SYZ*SYZ+SXZ*SXZ)
      DJ2=DJ2 * (1.D0/6.D0)
      DJ2=3.D0*DJ2
      DJ2=SQRT(DJ2)
C
      DF(1) = ((2.*SX) - SY -SZ)/2./DJ2 + ALC
      DF(2) = (-SX +(2.*SY) -SZ)/2./DJ2 + ALC
      DF(3) = (-SX -SY +(2.*SZ))/2./DJ2 + ALC
      DF(4) = 6. * SXY/2./DJ2
      DF(5) = 6. * SXZ/2./DJ2
      DF(6) = 6. * SYZ/2./DJ2
C
      RETURN
      END