Struct RebalancingWeightedTransactionSelector 

pub struct RebalancingWeightedTransactionSelector { /* private fields */ }

Implementations

impl RebalancingWeightedTransactionSelector

pub fn new(policy: Policy, transactions: Vec<CandidateTransaction>) -> Self

pub fn select_transactions(&mut self) -> Vec<Transaction>

select_transactions implements a probabilistic transaction selection algorithm. The algorithm, roughly, is as follows:

1. We assign a probability to each transaction equal to: (candidateTx.Value^alpha) / Σ(tx.Value^alpha) Where the sum of the probabilities of all txs is 1.
2. We draw a random number in [0,1) and select a transaction accordingly.
3. If it’s valid, add it to the selectedTxs and remove it from the candidates.
4. Continue iterating the above until we have either selected all available transactions or ran out of gas/block space.

Note that we make two optimizations here:

• Draw a number in [0,Σ(tx.Value^alpha)) to avoid normalization
• Instead of removing a candidate after each iteration, mark it for deletion. Once the sum of probabilities of marked transactions is greater than REBALANCE_THRESHOLD percent of the sum of probabilities of all transactions, rebalance.

select_transactions loops over the candidate transactions and appends the ones that will be included in the next block into selected_txs.

Trait Implementations

impl TemplateTransactionSelector for RebalancingWeightedTransactionSelector

fn select_transactions(&mut self) -> Vec<Transaction>

Expected to return a batch of transactions which were not previously selected. The batch will typically contain sufficient transactions to fill the block mass (along with the previously unrejected txs), or will drain the selector

fn reject_selection(&mut self, tx_id: TransactionId)

Should be used to report invalid transactions obtained from the most recent select_transactions call. Implementors should use this call to internally track the selection state and discard the rejected tx from internal occupation calculations

fn is_successful(&self) -> bool

Determine whether this was an overall successful selection episode