Adds the attribute variance_size to handle the number of elements taken
into account in the variance computation, instead of relying on
ss_list.size(), which is a mistake in the case of recalculate_average().
The option positioning.ss-similarity introduced in this commit allows to
chose the desired algorithm to compare two measurements. One can chose
between the historical mean euclidean distance algorithm and the new
algorithm using the number of values within the interval
[mean-std.dev.;mean+std.dev.].
The variance is now computed along with the average. Measurement has
three new attributes:
- average_mw (average in mW),
- variance,
- variance_m2 (variable used for the variance calculation).
In addition, average_ss has been renamed average_dbm (ditto for its
getter).
The computation method of the average has been changed to allow the
computation of the variance simultaneously.
To be consistent with the other modules, the positioning server must be
called OwlPS Positioner instead of Positioning, and the executable
owlps-positionerd (even if the daemon mode is not implemented yet).
That's a big commit for a tiny change.