C INVER2    SOURCE    CHAT      05/01/13    00:42:40     5004           
      SUBROUTINE INVER2(A,B,DET,ICRI)
C     CALCUL DE L'INVERSE DE LA MATRICE A
      IMPLICIT INTEGER(I-N)
      IMPLICIT REAL*8 (A-H,O-Z)  
      DIMENSION A(2,2),B(2,2)
      DATA EPSI/1.D-9/
      ICRI=0
      DET=A(1,1)*A(2,2)-A(2,1)*A(1,2)
      IF(ABS(DET).LE.EPSI) THEN
        ICRI=1
        RETURN
      END IF
      B(1,1)= A(2,2)/DET
      B(1,2)=-A(1,2)/DET
      B(2,1)=-A(2,1)/DET
      B(2,2)= A(1,1)/DET
      END