*==================================================================
 
      FUNCTION RKRAND(IDUMMY)
      IMPLICIT DOUBLE PRECISION(A-H,O-Z)
      SAVE
      DATA INIT/0/
      IF(INIT.EQ.0) THEN
        INIT=1
        X=DMOD(DSQRT(2D0),1D0)
        Y=DMOD(DSQRT(3D0),1D0)
        Z=DMOD(DSQRT(5D0),1D0)
      ELSE
        X=DMOD(X+Y+Z,1D0)
        Y=DMOD(X+Y+Z,1D0)
        Z=DMOD(X+Y+Z,1D0)
      ENDIF
      RKRAND=X
      END