[tor-dev] tor's definition of 'median'

[nusenu]

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Hi,

https://gitweb.torproject.org/torspec.git/tree/dir-spec.txt#n2028

> If 3 or more authorities provide a Measured= keyword for a router,
> the authorities produce a consensus containing a "w" Bandwidth=
> keyword equal to the median of the Measured= votes.

a random sample from recent votes:

grep 37.59.38.117 -A 3 *|grep Measured
w Bandwidth=6869 Measured=7570
w Bandwidth=6869 Measured=15500
w Bandwidth=6869 Measured=18100
w Bandwidth=6869 Measured=30500

Tor says the median value is
15500

2015-08-10-16-00-00-consensus:
w Bandwidth=15500

but the median of these 4 values is actually:
(18100+15500)/2 = 16800
no?

Has tor a different definition of 'median' and simply takes always the
second ordered measurement vote out of 4 votes or is there a bug in
the spec or implementation?
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