basic

This module describes several procedures to check for basic procedures of PrefLib instances.

is_approval(instance)

Checks whether the instance describes an approval profile. A profile is considered to represent approval ballots in two cases: All the orders are complete and consist of only two indifference classes; The orders are incomplete and consists of a single indifference class.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

A boolean indicating whether the instance describes an approval profile.

Return type:

bool

is_complete(instance)

Checks whether the instance describes a profile of complete preferences.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

A boolean indicating whether the instance describes a profile of complete preferences.

Return type:

bool

is_strict(instance)

Checks whether the instance describes a profile of strict preferences.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

A boolean indicating whether the instance describes a profile of strict preferences.

Return type:

bool

largest_ballot(instance)

Returns the size of the largest ballot of the instance, i.e., the maximum number of alternatives appearing in an order.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

The size of the largest ballot of the instance.

Return type:

int

largest_indif(instance)

Returns the size of the largest indifference class of any voter of the instance.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

The size of the largest indifference class of the instance.

Return type:

int

max_num_indif(instance)

Returns the maximum number of indifference classes over the orders of the instance.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

The maximum number of indifference classes of the instance.

Return type:

int

min_num_indif(instance)

Returns the minimum number of indifference classes over the orders of the instance.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

The minimum number of indifference classes of the instance.

Return type:

int

num_alternatives(instance)

Returns the number of alternatives of the instance.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

The number of alternatives of the instance.

Return type:

int

num_different_preferences(instance)

Returns the number of different orders of the instance.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

The number of different orders of the instance.

Return type:

int

num_voters(instance)

Returns the number of voters .

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

The number of voters of the instance.

Return type:

int

smallest_ballot(instance)

Returns the size of the smallest ballot of the instance, i.e., the smallest number of alternatives appearing in an order.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

The size of the smallest ballot of the instance.

Return type:

int

smallest_indif(instance)

Returns the size of the smallest indifference class of any voter of the instance.

Parameters:

instance (preflibtools.instances.preflibinstance.PreflibInstance) – The instance.

Returns:

The size of the smallest indifference class of the instance.

Return type:

int