def get_attestation_data_slot(state: BeaconState, data: AttestationData, config: Eth2Config) -> Slot: active_validator_indices = get_active_validator_indices( state.validators, data.target.epoch, ) committee_count = get_committee_count( len(active_validator_indices), config.SHARD_COUNT, config.SLOTS_PER_EPOCH, config.TARGET_COMMITTEE_SIZE, ) offset = ( data.crosslink.shard + config.SHARD_COUNT - get_start_shard( state, data.target.epoch, CommitteeConfig(config), ) ) % config.SHARD_COUNT committees_per_slot = committee_count // config.SLOTS_PER_EPOCH return compute_start_slot_of_epoch( data.target.epoch, config.SLOTS_PER_EPOCH, ) + offset // committees_per_slot
def _get_committee_count(state, epoch, config): active_validators = get_active_validator_indices(state.validators, epoch) return get_committee_count( len(active_validators), config.SHARD_COUNT, config.SLOTS_PER_EPOCH, config.TARGET_COMMITTEE_SIZE, )
def get_crosslink_deltas( state: BeaconState, config: Eth2Config) -> Tuple[Sequence[Gwei], Sequence[Gwei]]: rewards = tuple(0 for _ in range(len(state.validators))) penalties = tuple(0 for _ in range(len(state.validators))) epoch = state.previous_epoch(config.SLOTS_PER_EPOCH, config.GENESIS_EPOCH) active_validators_indices = get_active_validator_indices( state.validators, epoch) epoch_committee_count = get_committee_count( len(active_validators_indices), config.SHARD_COUNT, config.SLOTS_PER_EPOCH, config.TARGET_COMMITTEE_SIZE, ) epoch_start_shard = get_start_shard( state, epoch, CommitteeConfig(config), ) for shard_offset in range(epoch_committee_count): shard = Shard((epoch_start_shard + shard_offset) % config.SHARD_COUNT) crosslink_committee = set( get_crosslink_committee( state, epoch, shard, CommitteeConfig(config), )) _, attesting_indices = get_winning_crosslink_and_attesting_indices( state=state, epoch=epoch, shard=shard, config=config, ) total_attesting_balance = get_total_balance( state, attesting_indices, ) total_committee_balance = get_total_balance( state, crosslink_committee, ) for index in crosslink_committee: base_reward = get_base_reward(state, index, config) if index in attesting_indices: rewards = update_tuple_item_with_fn( rewards, index, lambda balance, delta: balance + delta, base_reward * total_attesting_balance // total_committee_balance) else: penalties = update_tuple_item_with_fn( penalties, index, lambda balance, delta: balance + delta, base_reward, ) return tuple(Gwei(reward) for reward in rewards), tuple( Gwei(penalty) for penalty in penalties)
def process_crosslinks(state: BeaconState, config: Eth2Config) -> BeaconState: current_epoch = state.current_epoch(config.SLOTS_PER_EPOCH) previous_epoch = state.previous_epoch(config.SLOTS_PER_EPOCH, config.GENESIS_EPOCH) new_current_crosslinks = state.current_crosslinks for epoch in (previous_epoch, current_epoch): active_validators_indices = get_active_validator_indices( state.validators, epoch) epoch_committee_count = get_committee_count( len(active_validators_indices), config.SHARD_COUNT, config.SLOTS_PER_EPOCH, config.TARGET_COMMITTEE_SIZE, ) epoch_start_shard = get_start_shard( state, epoch, CommitteeConfig(config), ) for shard_offset in range(epoch_committee_count): shard = Shard( (epoch_start_shard + shard_offset) % config.SHARD_COUNT) crosslink_committee = set( get_crosslink_committee( state, epoch, shard, CommitteeConfig(config), )) if not crosslink_committee: # empty crosslink committee this epoch continue winning_crosslink, attesting_indices = get_winning_crosslink_and_attesting_indices( state=state, epoch=epoch, shard=shard, config=config, ) threshold_met = _is_threshold_met_against_committee( state, attesting_indices, crosslink_committee, ) if threshold_met: new_current_crosslinks = update_tuple_item( new_current_crosslinks, shard, winning_crosslink, ) return state.copy( previous_crosslinks=state.current_crosslinks, current_crosslinks=new_current_crosslinks, )
def test_get_committee_count(active_validator_count, slots_per_epoch, target_committee_size, shard_count, expected_committee_count): assert expected_committee_count == get_committee_count( active_validator_count=active_validator_count, shard_count=shard_count, slots_per_epoch=slots_per_epoch, target_committee_size=target_committee_size, )
def _mk_attestation_inputs_in_epoch(epoch, state, config): active_validators_indices = get_active_validator_indices(state.validators, epoch) epoch_committee_count = get_committee_count( len(active_validators_indices), config.SHARD_COUNT, config.SLOTS_PER_EPOCH, config.TARGET_COMMITTEE_SIZE, ) epoch_start_shard = get_start_shard( state, epoch, CommitteeConfig(config), ) for shard_offset in random.sample(range(epoch_committee_count), epoch_committee_count): shard = Shard((epoch_start_shard + shard_offset) % config.SHARD_COUNT) committee = get_crosslink_committee( state, epoch, shard, CommitteeConfig(config), ) if not committee: # empty crosslink committee this epoch continue attestation_data = AttestationData( target=Checkpoint( epoch=epoch, ), crosslink=Crosslink( shard=shard, ), ) committee_count = len(committee) aggregation_bits = bitfield.get_empty_bitfield(committee_count) for index in range(committee_count): aggregation_bits = bitfield.set_voted(aggregation_bits, index) for index in committee: yield ( index, ( get_attestation_data_slot( state, attestation_data, config, ), ( aggregation_bits, attestation_data, ), ), )
def get_committee_assignment( state: BeaconState, config: Eth2Config, epoch: Epoch, validator_index: ValidatorIndex, ) -> CommitteeAssignment: """ Return the ``CommitteeAssignment`` in the ``epoch`` for ``validator_index``. ``CommitteeAssignment.committee`` is the tuple array of validators in the committee ``CommitteeAssignment.shard`` is the shard to which the committee is assigned ``CommitteeAssignment.slot`` is the slot at which the committee is assigned ``CommitteeAssignment.is_proposer`` is a bool signalling if the validator is expected to propose a beacon block at the assigned slot. """ next_epoch = state.next_epoch(config.SLOTS_PER_EPOCH) if epoch > next_epoch: raise ValidationError( f"Epoch for committee assignment ({epoch}) must not be after next epoch {next_epoch}." ) active_validators = get_active_validator_indices(state.validators, epoch) committees_per_slot = ( get_committee_count( len(active_validators), config.SHARD_COUNT, config.SLOTS_PER_EPOCH, config.TARGET_COMMITTEE_SIZE, ) // config.SLOTS_PER_EPOCH ) epoch_start_slot = compute_start_slot_of_epoch(epoch, config.SLOTS_PER_EPOCH) epoch_start_shard = get_start_shard(state, epoch, CommitteeConfig(config)) for slot in range(epoch_start_slot, epoch_start_slot + config.SLOTS_PER_EPOCH): offset = committees_per_slot * (slot % config.SLOTS_PER_EPOCH) slot_start_shard = (epoch_start_shard + offset) % config.SHARD_COUNT for i in range(committees_per_slot): shard = Shard((slot_start_shard + i) % config.SHARD_COUNT) committee = get_crosslink_committee( state, epoch, shard, CommitteeConfig(config) ) if validator_index in committee: is_proposer = validator_index == get_beacon_proposer_index( state.copy(slot=slot), CommitteeConfig(config) ) return CommitteeAssignment( committee, Shard(shard), Slot(slot), is_proposer ) raise NoCommitteeAssignment
def _find_collision(state, config, index, epoch): """ Given a target epoch, make the attestation expected for the validator w/ the given index. """ active_validators = get_active_validator_indices(state.validators, epoch) committees_per_slot = get_committee_count( len(active_validators), config.SHARD_COUNT, config.SLOTS_PER_EPOCH, config.TARGET_COMMITTEE_SIZE, ) // config.SLOTS_PER_EPOCH epoch_start_slot = compute_start_slot_of_epoch( epoch, config.SLOTS_PER_EPOCH, ) epoch_start_shard = get_start_shard(state, epoch, CommitteeConfig(config)) for slot in range(epoch_start_slot, epoch_start_slot + config.SLOTS_PER_EPOCH): offset = committees_per_slot * (slot % config.SLOTS_PER_EPOCH) slot_start_shard = (epoch_start_shard + offset) % config.SHARD_COUNT for i in range(committees_per_slot): shard = Shard((slot_start_shard + i) % config.SHARD_COUNT) committee = get_crosslink_committee(state, epoch, shard, CommitteeConfig(config)) if index in committee: # TODO(ralexstokes) refactor w/ tools/builder attestation_data = AttestationData( target=Checkpoint( epoch=epoch, ), crosslink=Crosslink( shard=shard, ), ) committee_count = len(committee) aggregation_bits = bitfield.get_empty_bitfield(committee_count) for i in range(committee_count): aggregation_bits = bitfield.set_voted(aggregation_bits, i) return { index: ( slot, (aggregation_bits, attestation_data) ) for index in committee } else: raise Exception("should have found a duplicate validator")
def get_crosslink_committees_at_slot( state: BeaconState, slot: Slot, config: Eth2Config ) -> Tuple[Tuple[Tuple[ValidatorIndex, ...], Shard], ...]: epoch = compute_epoch_of_slot(slot, config.SLOTS_PER_EPOCH) active_validators = get_active_validator_indices(state.validators, epoch) committees_per_slot = (get_committee_count( len(active_validators), config.SHARD_COUNT, config.SLOTS_PER_EPOCH, config.TARGET_COMMITTEE_SIZE, ) // config.SLOTS_PER_EPOCH) results = [] offset = committees_per_slot * (slot % config.SLOTS_PER_EPOCH) slot_start_shard = Shard( (get_start_shard(state, epoch, CommitteeConfig(config)) + offset) % config.SHARD_COUNT) for i in range(committees_per_slot): shard = (slot_start_shard + i) % config.SHARD_COUNT committee = get_crosslink_committee(state, epoch, shard, CommitteeConfig(config)) results.append((committee, Shard(shard))) return tuple(results)