inv3.F

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!||====================================================================
!||    inv3         ../starter/source/tools/univ/inv3.F
!||--- called by ------------------------------------------------------
!||    smorth3      ../starter/source/elements/solid/solide/smorth3.F
!||====================================================================
      SUBROUTINE inv3(A,B)
C----------------------------------------------------------
C   I m p l i c i t   T y p e s
C-----------------------------------------------
#include      "implicit_f.inc"
C----------------------------------------------------------
C   D u m m y   A r g u m e n t s   a n d   F u n c t i o n
C----------------------------------------------------------
      my_real a(9),b(9)
C-----------------------------------------------
C   L o c a l   V a r i a b l e s
C-----------------------------------------------
      my_real det
C=======================================================================
 
      det = a(1)*a(5)*a(9)+a(4)*a(8)*a(3)+a(7)*a(2)*a(6)
     .    - a(4)*a(2)*a(9)-a(1)*a(8)*a(6)-a(7)*a(5)*a(3)
 
      b(1) =  (a(5)*a(9)-a(6)*a(8)) / det
      b(4) = -(a(4)*a(9)-a(6)*a(7)) / det
      b(7) =  (a(4)*a(8)-a(5)*a(7)) / det
 
      b(2) = -(a(2)*a(9)-a(3)*a(8)) / det
      b(5) =  (a(1)*a(9)-a(3)*a(7)) / det
      b(8) = -(a(1)*a(8)-a(2)*a(7)) / det
 
      b(3) =  (a(2)*a(6)-a(3)*a(5)) / det
      b(6) = -(a(1)*a(6)-a(3)*a(4)) / det
      b(9) =  (a(1)*a(5)-a(2)*a(4)) / det
C-----------------------------------------------
      RETURN
      END SUBROUTINE inv3