c+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
      subroutine rannor(a,b)
c---a,b are gaussian random numbers of mean 0 and variance 1
c---uses random number generator supplied with parmela
      include 'constcom.h'
      
      y = sandom(d)
      z = sandom(d)
      x = twopi*z
      a1 = sqrt(-2.0*alog(y))
      a = a1*sin(x)
      b = a1*cos(x)
      return
      end