func vote(client types.RepPoolClient, instance instance.Instance, representatives []string) (string, float64, error) {
results := client.Vote(representatives, instance)
winningScore := 1e9
winners := []string{}
for _, result := range results {
if result.Error != "" {
continue
}
if result.Score < winningScore {
winningScore = result.Score
winners = []string{result.Rep}
} else if result.Score == winningScore { // can be less strict here
winners = append(winners, result.Rep)
}
}
if len(winners) == 0 {
return "", 0, AllBiddersFull
}
winner := winners[util.R.Intn(len(winners))]
return winner, winningScore, nil
}
func Auction(client types.RepPoolClient, auctionRequest types.AuctionRequest) types.AuctionResult {
var auctionWinner string
var representatives []string
if !auctionRequest.Rules.RepickEveryRound {
representatives = randomSubset(auctionRequest.RepGuids, auctionRequest.Rules.MaxBiddingPool)
}
numRounds, numVotes := 0, 0
t := time.Now()
for round := 1; round <= auctionRequest.Rules.MaxRounds; round++ {
if auctionRequest.Rules.RepickEveryRound {
representatives = randomSubset(auctionRequest.RepGuids, auctionRequest.Rules.MaxBiddingPool)
}
numRounds++
winner, _, err := vote(client, auctionRequest.Instance, representatives)
numVotes += len(representatives)
if err != nil {
continue
}
c := make(chan types.VoteResult)
go func() {
winnerScore, err := client.ReserveAndRecastVote(winner, auctionRequest.Instance)
result := types.VoteResult{
Rep: winner,
}
if err != nil {
result.Error = err.Error()
c <- result
return
}
result.Score = winnerScore
c <- result
}()
secondRoundVoters := []string{}
for _, rep := range representatives {
if rep != winner {
secondRoundVoters = append(secondRoundVoters, rep)
}
}
_, secondPlaceScore, err := vote(client, auctionRequest.Instance, secondRoundVoters)
winnerRecast := <-c
numVotes += len(representatives)
if winnerRecast.Error != "" {
//winner ran out of space on the recast, retry
continue
}
if err == nil && secondPlaceScore < winnerRecast.Score && round < auctionRequest.Rules.MaxRounds {
client.Release(winner, auctionRequest.Instance)
continue
}
client.Claim(winner, auctionRequest.Instance)
auctionWinner = winner
break
}
return types.AuctionResult{
Winner: auctionWinner,
Instance: auctionRequest.Instance,
NumRounds: numRounds,
NumVotes: numVotes,
Duration: time.Since(t),
}
}