C INVERT    SOURCE    CHAT      05/01/13    00:42:55     5004           
      SUBROUTINE INVERT(A,B,DET,ICRI)
C     CALCULDE L'INVERSE DE LA MATRICE A
      IMPLICIT INTEGER(I-N)
      IMPLICIT REAL*8 (A-H,O-Z)  
      DIMENSION A(3,3),B(3,3)
      DATA EPSI/1.D-9/
      ICRI=0
      CALL DETERM(A,DET)
      IF(DABS(DET).LE.EPSI) THEN
        ICRI=1
        RETURN
      END IF
      B(1,1)= A(2,2)*A(3,3)-A(3,2)*A(2,3)
      B(1,2)=-A(1,2)*A(3,3)+A(3,2)*A(1,3)
      B(1,3)= A(1,2)*A(2,3)-A(2,2)*A(1,3)
      B(2,1)=-A(2,1)*A(3,3)+A(3,1)*A(2,3)
      B(2,2)= A(1,1)*A(3,3)-A(3,1)*A(1,3)
      B(2,3)=-A(1,1)*A(2,3)+A(2,1)*A(1,3)
      B(3,1)= A(2,1)*A(3,2)-A(2,2)*A(3,1)
      B(3,2)=-A(1,1)*A(3,2)+A(3,1)*A(1,2)
      B(3,3)= A(1,1)*A(2,2)-A(2,1)*A(1,2)
      DO 10 I=1,3
      DO 10 J=1,3
  10  B(I,J)=B(I,J)/DET
      END