Add epoch transition to spec #63
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| @@ -36,6 +38,7 @@ def s(self): | |||
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| # An absolute unique indentifier of a slot, counting incrementally from 0 | |||
| @dataclass | |||
| @functools.total_ordering | |||
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cool, didn't know about this
| if new_chain == self.local_chain: | ||
| # we have not re-org'd therefore we can simply update our ledger state | ||
| # if this block extend our local chain | ||
| if self.local_chain.tip() == block: | ||
| self.ledger_state.apply(block) | ||
| else: | ||
| # we have re-org'd, therefore we must roll back out ledger state and | ||
| # re-apply blocks from the new chain | ||
| ledger_state = self.genesis_state.copy() | ||
| for block in new_chain.blocks: | ||
| ledger_state.apply(block) | ||
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| self.ledger_state = ledger_state | ||
| self.local_chain = new_chain | ||
| new_state = self.ledger_state[block.parent].copy() | ||
| new_state.apply(block) | ||
| self.ledger_state[block.id()] = new_state |
cryptarchia/cryptarchia.py
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| @@ -27,24 +28,39 @@ class TimeConfig: | |||
| class Config: | |||
| k: int | |||
| active_slot_coeff: float # 'f', the rate of occupied slots | |||
| # The numerator multiplier in the formula used for calculating the number of slots in an epoch. | |||
| # An epoch is exactly int(floor(epoch_length_multiplier * k / f slots)) long. | |||
| epoch_length_multiplier: int | |||
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epoch length is derived from the stabilization periods of the different snapshots taken within an epoch.
Thus, the target is (4 + 3 + 3) * k / f
where 4 is for stabilizing the stake freezing snapshot, 3 is the buffer between frozen stake and nonce snapshot, and the last 3 is for stabilizing the nonce snapshot.
how about we decompose this multiple into those three periods?
epoch_period_stake_distribution: int
epoch_period_nonce_buffer: int
epoch_period_nonce: int
@property
def base_period_length(self) -> int:
return int(floor(self.k / self.active_slot_coeff))
@property
def epoch_length(self) -> int:
return (self.epoch_period_stake_distribution_stabilization
+ self.epoch_period_nonce_buffer
+ self.epoch_period_nonce_stabilization) * self.base_period_lengthThen we can use these period configs when creating snapshots
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Makes sense, and makes it impossible to configure values that do not make sense (e.g. seting epoch_length_multiplier to say 2 when the nonce snapshot is taken after 7k/f)
| commitments=self.commitments.copy(), | ||
| nullifiers=self.nullifiers.copy(), | ||
| commitments=deepcopy(self.commitments), | ||
| nullifiers=deepcopy(self.nullifiers), |
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these commitments/nullifiers are never changed no? I didn't think there was a risk to a shallow copy.
But better to be paranoid 👍
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We add the nullifier of the new leader proof, so yes that changes
cryptarchia/cryptarchia.py
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| def get_last_valid_state(self, chain: Chain, slot: Slot) -> LedgerState: | ||
| for block in reversed(chain.blocks): | ||
| if block.slot < slot: | ||
| return self.ledger_state[block.id()] | ||
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| @dataclass | ||
| class EpochState: | ||
| # for details of snapshot schedule please see: | ||
| # https://github.com/IntersectMBO/ouroboros-consensus/blob/fe245ac1d8dbfb563ede2fdb6585055e12ce9738/docs/website/contents/for-developers/Glossary.md#epoch-structure | ||
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| # The stake distribution snapshot is taken at the beginning of the previous epoch | ||
| stake_distribution_snapshot: LedgerState | ||
| return self.genesis_state |
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What does "valid" mean here? how about just state_at_slot(...)?
cryptarchia/cryptarchia.py
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| nonce_slot = Slot( | ||
| int(floor(7 * self.config.k / self.config.active_slot_coeff)) | ||
| + stake_snapshot_slot.absolute_slot | ||
| ) |
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yeah I think putting the epoch periods in the config would make this code clearer
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