Class ApportionmentMethods

java.lang.Object

org.episteme.social.politics.ApportionmentMethods

public final class ApportionmentMethods
extends Object

Provides mathematical methods for electoral seat apportionment. Includes implementations of D'Hondt, Sainte-Laguë, Hamilton, and Huntington-Hill methods.

Since:

1.0

Version:

1.1

Author:

Silvere Martin-Michiellot, Gemini AI (Google DeepMind)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	ApportionmentMethods.ApportionmentResult	Aggregated results of an apportionment calculation.
static final record	ApportionmentMethods.Party	Simple party representation for apportionment.

Method Summary

Modifier and Type	Method	Description
static double	calculateGallagher(List<ApportionmentMethods.Party> parties, Map<String,Integer> seats, int totalSeats)	Calculates the Gallagher index of disproportionality.
static Map<String, ApportionmentMethods.ApportionmentResult>	compareAllMethods(List<ApportionmentMethods.Party> parties, int totalSeats)	Compares all implemented methods for a given set of data.
static ApportionmentMethods.ApportionmentResult	dHondt(List<ApportionmentMethods.Party> parties, int totalSeats)	D'Hondt method - tends to favor larger parties.
static Real	effectiveThreshold(int totalSeats)	Calculates the effective electoral threshold.
static ApportionmentMethods.ApportionmentResult	hamilton(List<ApportionmentMethods.Party> parties, int totalSeats)	Hamilton (Largest Remainder) method with Hare quota.
static ApportionmentMethods.ApportionmentResult	huntingtonHill(List<ApportionmentMethods.Party> parties, int totalSeats, int minimumPerParty)	Huntington-Hill method, used for the US House of Representatives.
static ApportionmentMethods.ApportionmentResult	sainteLague(List<ApportionmentMethods.Party> parties, int totalSeats)	Sainte-Laguë method - generally considered more proportional than D'Hondt.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

dHondt

public static ApportionmentMethods.ApportionmentResult dHondt(List<ApportionmentMethods.Party> parties,
 int totalSeats)

D'Hondt method - tends to favor larger parties.

Parameters:

parties - list of parties and their vote counts

totalSeats - number of seats to allocate

Returns:

the apportionment result

sainteLague

public static ApportionmentMethods.ApportionmentResult sainteLague(List<ApportionmentMethods.Party> parties,
 int totalSeats)

Sainte-Laguë method - generally considered more proportional than D'Hondt.

Parameters:

parties - list of parties and their vote counts

totalSeats - number of seats to allocate

Returns:

the apportionment result

hamilton

public static ApportionmentMethods.ApportionmentResult hamilton(List<ApportionmentMethods.Party> parties,
 int totalSeats)

Hamilton (Largest Remainder) method with Hare quota.

Parameters:

parties - list of parties and their vote counts

totalSeats - number of seats to allocate

Returns:

the apportionment result

huntingtonHill

public static ApportionmentMethods.ApportionmentResult huntingtonHill(List<ApportionmentMethods.Party> parties,
 int totalSeats,
 int minimumPerParty)

Huntington-Hill method, used for the US House of Representatives.

Parameters:

parties - list of parties and their vote counts

totalSeats - number of seats to allocate

minimumPerParty - minimum seats guaranteed per party

Returns:

the apportionment result

compareAllMethods

public static Map<String, ApportionmentMethods.ApportionmentResult> compareAllMethods(List<ApportionmentMethods.Party> parties,
 int totalSeats)

Compares all implemented methods for a given set of data.

Parameters:

parties - list of parties and their vote counts

totalSeats - number of seats to allocate

Returns:

map of method names to results

calculateGallagher

public static double calculateGallagher(List<ApportionmentMethods.Party> parties,
 Map<String,Integer> seats,
 int totalSeats)

Calculates the Gallagher index of disproportionality. Lower values indicate more proportional representation.

Parameters:

parties - parties involved

seats - allocated seats

totalSeats - total pool of seats

Returns:

the calculated index

effectiveThreshold

public static Real effectiveThreshold(int totalSeats)

Calculates the effective electoral threshold.

Parameters:

totalSeats - total seats in the district/election

Returns:

the threshold percentage as a Real number