JS function for calculating Danish mandates

[ndarville]

Links

• http://www.matematiksider.dk/mandatfordelinger.html

  Config

Denmark's mandate calculation:

Votes	Selection
4	Chosen overseas
135	D'Hondt
40	Sainte-League

mandates = dHondt(votes, 135) + sainteLeague(votes, 40);

var partyAmount = null, // 12 --- for each row where vote share is above threshold
    seatAmount = null, // 179
    population = null, // 5000000
    threshold = null, // in per cent; e.g. 2
    columns = function(seatAmount) {}; // find more optimal value than seatAmount

Steps

1

D'Hondt

Create a table with

• a header row and {{ partyAmount }} rows

• a party-name and vote-amount column and {{ seatAmount }} columns

  Party	Votes	1	2	3	...	seatAmount
  A	v_A	v_A/1	v_A/2	v_A/3	...	v_A/seatAmount
  B	v_B	v_B/1	v_B/2	v_B/3	...	v_B/seatAmount
  C	v_C	v_C/1	v_C/2	v_C/3	...	v_C/seatAmount

  Saine-League

Create a table with

• (...)

• (...) and {{ seatAmount }}/2 columns of uneven numbers

  Party	Votes	1	3	5	...	seatAmount.uneven
  A	v_A	v_A/1	v_A/3	v_A/3	...	v_A/seatAmount.uneven
  B	v_B	v_B/1	v_B/3	v_B/3	...	v_B/seatAmount.uneven
  C	v_C	v_C/1	v_C/3	v_C/3	...	v_C/seatAmount.uneven

  2

Pick the {{ partyAmount }} largest values

Party	Votes	1	2	3	...	seatAmount
A	v_A	*v_A/1	*v_A/2	v_A/3	...	v_A/seatAmount
B	v_B	*v_B/1	v_B/2	v_B/3	...	v_B/seatAmount
C	v_C	v_C/1	v_C/2	v_C/3	...	v_C/seatAmount

3

Summary:

• Party A: 2 mandates for #1 + #2
• Party B: 1 mandate_ for #1

• Party C: 0 mandates

  Party	Votes	1	2
  A	v_A	1	1
  B	v_B	1	0
  C	v_C	0	0

[ndarville]

1. http://politiskkompas.blogspot.com/2014/04/lidt-valgmatematik-i.html
2. http://politiskkompas.blogspot.com/2014/04/lidt-valgmatematik-ii.html
3. http://intranet.odensekatedralskole.dk/~ph/matematik/2007g/Elklit_Valgsystemer_2005.pdf