C RANFUNC   SOURCE    FANDEUR   13/01/29    21:16:22     7683           
      FUNCTION Ranfunc(sigma,i3,i6,parahot3,idimpara3,lcp)

c     Rankine function to describe the tensile part of a concrete material
c     sigmaeq = S1 = largest principal stress

      IMPLICIT REAL*8 (A-B,D-H,O-Z)
      implicit integer (I-K,M,N)
      implicit logical (L)
      implicit character*10 (C)         

      dimension sigma(i6)
****  dimension rcossigmapr(i3,i3),sigmacp(3),vloc(3),vloc1(1)
      dimension rcossigmapr(3,3),sigmacp(3),vloc(3),vloc1(1)
      dimension parahot3(idimpara3),P1(3,3),pi1(3)
*****
*     MESSAGES D'ERREUR ( SUPPRESSION DES AUTOMATIC OBJECTS)
      IF(I3.GT.3) PRINT *, ' RANFUNC - ERREUR  I3 = ', I3, ' > 1 '
*****
      call sigmapr3ETC(sigma,S1,S2,S3,rcossigmapr,lcp)
c          =============
c     algorithm to find the eigen values and eigen vectors of symmetric matrix sigma

      Ranfunc = s1

      RETURN
      END