Struct elastic_elgamal::app::QuadraticVotingParams

pub struct QuadraticVotingParams<G: Group> { /* private fields */ }

Quadratic voting parameters prepared for a certain Group.

The parameters are:

• Receiver key using which votes in QuadraticVotingBallots are encrypted
• Number of options in the ballot
• Number of credits per ballot
• Maximum number of votes per option

See QuadraticVotingBallot for a detailed description of parameters.

Examples

let (receiver, _) = Keypair::<Ristretto>::generate(&mut thread_rng())
    .into_tuple();
let mut params = QuadraticVotingParams::new(receiver, 5, 20);
// 5 options, 20 credits.
assert_eq!(params.options_count(), 5);
assert_eq!(params.credits(), 20);
// By default, max votes per option are determined based on credits
assert_eq!(params.max_votes(), 4); // 4 < sqrt(20) < 5

// It is possible to reduce max votes per ballot.
params.set_max_votes(3);
assert_eq!(params.max_votes(), 3);

Implementations

impl<G: Group> QuadraticVotingParams<G>

pub fn new(receiver: PublicKey<G>, options: usize, credits: u64) -> Self

Creates new parameters for the specified number of credits allocated per voter.

The maximum number of votes per option is automatically set as floor(sqrt(credits)); it can be changed via Self::set_max_votes().

Panics

Panics if the number of options or credits is zero.

pub fn receiver(&self) -> &PublicKey<G>

Returns the public key for which the QuadraticVotingBallots are encrypted.

pub fn options_count(&self) -> usize

Returns the number of options.

pub fn credits(&self) -> u64

Returns the number of credits per ballot.

pub fn max_votes(&self) -> u64

Returns the maximum number of votes per option.

pub fn set_max_votes(&mut self, max_votes: u64)

Sets the maximum number of votes per option.

Panics

Panics if max_votes * max_votes exceeds credits; in this case, this number of votes cannot be cast for a single option.

Trait Implementations

impl<G: Clone + Group> Clone for QuadraticVotingParams<G>

fn clone(&self) -> QuadraticVotingParams<G>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<G: Debug + Group> Debug for QuadraticVotingParams<G>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.