/**
* Returns the set of songs which are proposed by the agents.
*
* @param proposalTimes
* @return The songs
*/
private List<BaseSong<BaseArtist, BaseAlbum>> getProposedSongs(AgentsTiming proposalTimes) {
Set<IAgent> agents = agentManager.getAgents();
// Using set here to ensure no duplicate entries
Set<BaseSong<BaseArtist, BaseAlbum>> proposedSongs =
new HashSet<BaseSong<BaseArtist, BaseAlbum>>(SONG_PROPOSAL_USAGE_COUNT * agents.size());
for (IAgent agent : agents) {
throwIfAborted();
StopWatch stopWatch = StopWatch.start();
List<BaseSong<BaseArtist, BaseAlbum>> agentProposals =
new ArrayList<BaseSong<BaseArtist, BaseAlbum>>(agent.suggestSongs(SONG_PROPOSAL_COUNT));
// Get #SONG_PROPOSAL_USAGE_COUNT items of them at random
while (agentProposals.size() > SONG_PROPOSAL_USAGE_COUNT) {
agentProposals.remove(RandomProvider.getRandom().nextInt(agentProposals.size()));
}
proposedSongs.addAll(agentProposals);
proposalTimes.addAgentTiming(agent, stopWatch.stop());
}
return new ArrayList<BaseSong<BaseArtist, BaseAlbum>>(proposedSongs);
}
/**
* Returns the average votes of the agents for the given songs. The votes gets weighted by the
* importance of the agents.
*
* @param proposedSongs The proposed songs
* @param agentsVotes (out) The votes for all the songs by agent
* @param voteTimes
* @return The weighted mean votes for the songs
*/
private Map<BaseSong<BaseArtist, BaseAlbum>, Double> getVotesForProposed(
List<BaseSong<BaseArtist, BaseAlbum>> proposedSongs,
Map<IAgent, List<SongVote>> agentsVotes,
AgentsTiming voteTimes) {
Set<IAgent> agents = agentManager.getAgents();
// Init the ratings list & the weight sum table
Map<BaseSong<BaseArtist, BaseAlbum>, Double> votes =
new HashMap<BaseSong<BaseArtist, BaseAlbum>, Double>();
Map<BaseSong<BaseArtist, BaseAlbum>, Double> weightSums =
new HashMap<BaseSong<BaseArtist, BaseAlbum>, Double>(agents.size());
for (BaseSong<BaseArtist, BaseAlbum> song : proposedSongs) {
votes.put(song, 0.0d);
weightSums.put(song, 0.0d);
}
// Calculate the song ratings
for (IAgent agent : agents) {
throwIfAborted();
// Get the agent vote
List<SongVote> agentVotes;
StopWatch stopWatch = StopWatch.start();
{
agentVotes = agent.vote(Collections.unmodifiableList(proposedSongs));
}
voteTimes.addAgentTiming(agent, stopWatch.stop());
// Fill up the list to ensure that a vote for all songs exist
List<BaseSong<BaseArtist, BaseAlbum>> noVote =
new ArrayList<BaseSong<BaseArtist, BaseAlbum>>(proposedSongs);
for (int i = 0; i < agentVotes.size(); ) {
final SongVote vote = agentVotes.get(i);
int idx = noVote.indexOf(vote.getSong());
if (idx >= 0) {
noVote.remove(idx);
++i;
} else {
// No vote for this song is required
agentVotes.remove(i);
}
}
for (BaseSong<BaseArtist, BaseAlbum> song : noVote) {
agentVotes.add(new SongVote(song, 0.0f));
}
agentsVotes.put(agent, agentVotes);
for (SongVote vote : agentVotes) {
final BaseSong<BaseArtist, BaseAlbum> song = vote.getSong();
double oldRating = votes.get(song);
double agentWeight = getAgentWeights().get(agent);
double oldW = weightSums.get(song);
double newW = oldW + agentWeight;
double newRating =
(oldRating * oldW + vote.getVote() * agentWeight)
/ newW; // Continuous, weighted mean calculation
votes.put(song, newRating);
weightSums.put(song, newW);
}
}
return votes;
}