C KDOM3B    SOURCE    CHAT      05/01/13    00:54:03     5004
      SUBROUTINE KDOM3B(X1,Y1,X3,Y3,VOLU,X2,Y2)
C
C************************************************************************
C
C PROJET            :  CASTEM 2000
C
C NOM               :  KDOM3B
C
C DESCRIPTION       :  Subroutine called by KDOM3A and KDOM4C
C                      Axial-symmetric case
C                      We compute
C                      the surface of the 2D line
C                      its center of gravity
C
C LANGAGE           :  FORTRAN 77 + ESOPE 2000 (avec estensions CISI)
C
C AUTEUR            :  A. BECCANTINI, DRN/DMT/SEMT/LTMF
C
C************************************************************************
C
C INPUT             : (X1,Y1), (X3,Y3) coordinates of the line extrema
C
C OUTPUT            : VOLUME: surface
C                     (X2,Y2) center of gravity
C
C************************************************************************
C
C Created the 24/02/04
C
C
      IMPLICIT INTEGER(I-N)
      REAL*8 X1,Y1,X3,Y3,X2,Y2,RL13,VOLU,W1,W2
C
      W1=1.0D0-(1.0D0/(3.0D0**0.5D0))
      W2=1.0D0+(1.0D0/(3.0D0**0.5D0))
C
      RL13 = ((Y3-Y1)*(Y3-Y1)) + ((X3-X1)*(X3-X1))
      RL13 = RL13**0.5D0
      VOLU=0.5D0*(X1+X3)*RL13
      X2=0.125D0*RL13*(((X1*W1+X3*W2)**2)+((X1*W2+X3*W1)**2))
      X2=X2/VOLU
      Y2=0.125D0*RL13*(((X1*W1+X3*W2)*(Y1*W1+Y3*W2))+
     &     ((X3*W1+X1*W2)*(Y3*W1+Y1*W2)))
      Y2=Y2/VOLU
      RETURN
      END