As discussed in section 
, before any optimisation could
be performed, the minimum number of 
required to adequately describe
needed to be established. This was achieved by performing a series
of VMC calculations in which the number of stars used in the
expansion of was slowly decreased. These calculations showed
that the number of stars used in () could be
drastically reduced. In fact, as few as 6-10 stars were adequate to
describe to within the numerical error of the calculation.