Quick Start

Now that you have installed trivoting (if not, see Installation), you can start using the package!

On this page, we will guide you through a simple example.

Describing a Trichotomous Profile

Alternatives

The fundamental elements are the alternatives, i.e., the entities that will be voted upon. We define them using the class Alternative.

from trivoting.election import Alternative

a1 = Alternative("a1")   # The constructor takes the name of the alternative
a2 = Alternative("a2")
a3 = Alternative("a3")

Trichotomous Ballots

With the alternatives we can define a trichotomous ballot. These are defined via the class TrichotomousBallot.

from trivoting.election import TrichotomousBallot

b1 = TrichotomousBallot(approved=[a1, a2], disapproved=[a3])
b2 = TrichotomousBallot(approved=[a1])  # approved and/or disapproved can be omitted
b3 = TrichotomousBallot(disapproved=[a3])

We can now define a trichotomous profile:

from trivoting.election import TrichotomousProfile

profile = TrichotomousProfile([b1, b2], alternatives={a1, a2, a3})  # Specify all the available alternatives
profile.append(b3)   # Use list methods to handle the profile

Computing a Selection of Alternatives

With the profile being defined, we can now start computing selections of alternatives. Rules for selecting alternatives are defined in the module rules.

from trivoting.rules import proportional_approval_voting

max_selection_size = 2  # This is an upper bound on the size of the selection
selection = proportional_approval_voting(profile, max_selection_size)