C DIACL     SOURCE    CHAT      05/01/12    22:49:34     5004           
        SUBROUTINE DIACL(EPS,SIN,COS)
      IMPLICIT INTEGER(I-N)
        IMPLICIT REAL*8(A-H,O-Z)
C
C       EPS = TABLEAU DES DEFORMATIONS (EPS11,EPS22,SQRT(2)*EPS12)
C       EPSL1 = DEFORMATIONS PRINCIPALES
C       SIN ET COS = SINUS ET COSINUS DE L"ANGLE DE ROTATION
        DIMENSION  EPS(3)
C
        EPS12=EPS(3)/2.D0
        X1=2.D0*EPS12
        X2=EPS(1)-EPS(2)
        X3=SQRT(X1**2+X2**2)
        X8=X2*1.D+10
        IF (DABS(X1).GT.DABS(X8).OR.X2.EQ.0.D0) THEN
          COS=0.5D0*SQRT(2.D0)
          SIN=SIGN(COS,X1)
        ELSE
          X4=X1/X2
          X5=1.D0+X4**2
          X5=SIGN(1.D0,X2)/SQRT(X5)
          X6=(1.D0+X5)*0.5D0
          X6=SQRT(X6)
          X7=(1.D0-X5)*0.5D0
          X7=SIGN(1.D0,X1)*SQRT(X7)
          COS=X6
          SIN=X7
        END IF
C
        RETURN
        END