From f57387cc83f16e2ec6b19ee544964254786fa7fa Mon Sep 17 00:00:00 2001 From: Dankrad Feist Date: Thu, 27 Jun 2019 13:09:48 +0100 Subject: [PATCH] Justification bitvector length to constant --- specs/core/0_beacon-chain.md | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index c1f1a7bcf..4d3fe9773 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -189,6 +189,7 @@ The following values are (non-configurable) constants used throughout the specif | `MIN_PER_EPOCH_CHURN_LIMIT` | `2**2` (= 4) | | `CHURN_LIMIT_QUOTIENT` | `2**16` (= 65,536) | | `SHUFFLE_ROUND_COUNT` | `90` | +| `JUSTIFICATION_BITVECTOR_LENGTH` | `4` | * For the safety of crosslinks, `TARGET_COMMITTEE_SIZE` exceeds [the recommended minimum committee size of 111](https://vitalik.ca/files/Ithaca201807_Sharding.pdf); with sufficient active validators (at least `SLOTS_PER_EPOCH * TARGET_COMMITTEE_SIZE`), the shuffling algorithm ensures committee sizes of at least `TARGET_COMMITTEE_SIZE`. (Unbiasable randomness with a Verifiable Delay Function (VDF) will improve committee robustness and lower the safe minimum committee size.) @@ -523,7 +524,7 @@ class BeaconState(Container): previous_justified_root: Hash # Previous epoch snapshot current_justified_epoch: Epoch current_justified_root: Hash - justification_bitfield: Bitvector[4] # Bit set for every recent justified epoch + justification_bitfield: Bitvector[JUSTIFICATION_BITVECTOR_LENGTH] # Bit set for every recent justified epoch # Finality finalized_epoch: Epoch finalized_root: Hash @@ -1291,21 +1292,21 @@ def process_justification_and_finalization(state: BeaconState) -> None: # Process justifications state.previous_justified_epoch = state.current_justified_epoch state.previous_justified_root = state.current_justified_root - state.justification_bitfield = Bitvector[4](*([0] + state.justification_bitfield[0:3])) + state.justification_bitfield = Bitvector[4](*([0b0] + state.justification_bitfield[0:JUSTIFICATION_BITVECTOR_LENGTH - 1])) previous_epoch_matching_target_balance = get_attesting_balance( state, get_matching_target_attestations(state, previous_epoch) ) if previous_epoch_matching_target_balance * 3 >= get_total_active_balance(state) * 2: state.current_justified_epoch = previous_epoch state.current_justified_root = get_block_root(state, state.current_justified_epoch) - state.justification_bitfield[1] = True + state.justification_bitfield[1] = 0b1 current_epoch_matching_target_balance = get_attesting_balance( state, get_matching_target_attestations(state, current_epoch) ) if current_epoch_matching_target_balance * 3 >= get_total_active_balance(state) * 2: state.current_justified_epoch = current_epoch state.current_justified_root = get_block_root(state, state.current_justified_epoch) - state.justification_bitfield[0] = True + state.justification_bitfield[0] = 0b1 # Process finalizations bitfield = state.justification_bitfield