Multiple starting points for phase determination are created by the magic integer method which is described
in [39].
The values of
phases,
, may be expressed in the form of a set of
equations by multiplying a
variable
by successive magic integers,
in each equation,

for
. Any set of phases with values between
and
may be approximately
represented in this way as a set of values ranging from
and
with the appropriate choice of
,
where
also takes values between 0 and 1.
There will in general be a residual error,
, in the representation
of
which depends on the choice of magic integers [79] [80].
The r.m.s. error in the phase representation is
.
A starting set of phases is produced by choosing several values of
at
intervals which permute
the phases
such that the mean change in
, as x is incremented, is approximately equal
to
. The advantage of magic integer permutations over quadrant permutations (where each
phase takes one of the four values,
,
,
or
) is the large reduction in the
number of permutations required to efficiently sample the
-phase space.
Suitable magic integers have been
found to be those of the Fibonacci series defined as (
), with
.