real function randn
     m         (k)
c
c     + + + PURPOSE + + +
c     Provides random numbers ranging from 0.0 to 1.0
c
c     + + + ARGUMENT DECLARATIONS + + +
      integer k(4)
c
c     + + + ARGUMENT DEFINITIONS + + +
c     k           - Seed for random number generation.
c
c     + + + END SPECIFICATIONS + + +

      integer i
c
 10   continue
      k(4)=3*k(4)+k(2)
      k(3)=3*k(3)+k(1)
      k(2)=3*k(2)
      k(1)=3*k(1)
      i=k(1)/1000
      k(1)=k(1)-i*1000
      k(2)=k(2)+i
      i=k(2)/100
      k(2)=k(2)-100*i
      k(3)=k(3)+i
      i=k(3)/1000
      k(3)=k(3)-i*1000
      k(4)=k(4)+i
      i=k(4)/100
      k(4)=k(4)-100*i
      randn=(((float(k(1))*.001+float(k(2)))*.01+float(k(3)))*.001+
     1      float(k(4)))*.01
c ---- range check:
      if(randn .le. 0.0 .or. randn .ge. 1.0) goto 10
c
      return
      end