status-im
/
eth2.0-specs
mirror of https://github.com/status-im/eth2.0-specs.git
2
0
Fork 0
Code Issues Projects Releases Wiki Activity

Update fork choice rule (#571)

This commit is contained in:
vbuterin 2019-02-06 10:34:19 -06:00 committed by Justin
parent ec1a08278b
commit 8f37c5c0f8
1 changed files with 19 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
specs/core/0_beacon-chain.md
View File

@ -13,6 +13,7 @@
- [Constants](#constants)
- [Misc](#misc)
- [Deposit contract](#deposit-contract)
- [Gwei values](#gwei-values)
- [Initial values](#initial-values)
- [Time parameters](#time-parameters)
- [State list lengths](#state-list-lengths)
@ -179,7 +180,6 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be
| - | - | :-: |
| `SHARD_COUNT` | `2**10` (= 1,024) | shards |
| `TARGET_COMMITTEE_SIZE` | `2**7` (= 128) | [validators](#dfn-validator) |
| `EJECTION_BALANCE` | `2**4 * 1e9` (= 16,000,000,000) | Gwei |
| `MAX_BALANCE_CHURN_QUOTIENT` | `2**5` (= 32) | - |
| `BEACON_CHAIN_SHARD_NUMBER` | `2**64 - 1` | - |
| `MAX_INDICES_PER_SLASHABLE_VOTE` | `2**12` (= 4,096) | votes |
@ -189,12 +189,19 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be
### Deposit contract
| Name | Value |
| - | - |
| `DEPOSIT_CONTRACT_ADDRESS` | **TBD** |
| `DEPOSIT_CONTRACT_TREE_DEPTH` | `2**5` (= 32) |
### Gwei values
| Name | Value | Unit |
| - | - | :-: |
| `DEPOSIT_CONTRACT_ADDRESS` | **TBD** |
| `DEPOSIT_CONTRACT_TREE_DEPTH` | `2**5` (= 32) | - |
| `MIN_DEPOSIT_AMOUNT` | `2**0 * 1e9` (= 1,000,000,000) | Gwei |
| `MAX_DEPOSIT_AMOUNT` | `2**5 * 1e9` (= 32,000,000,000) | Gwei |
| `FORK_CHOICE_BALANCE_INCREMENT` | `2**0 * 1e9` (= 1,000,000,000) | Gwei |
| `EJECTION_BALANCE` | `2**4 * 1e9` (= 16,000,000,000) | Gwei |
### Initial values
@ -1555,8 +1562,8 @@ def get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBl
return get_ancestor(store, store.get_parent(block), slot)
```
* Let `get_latest_attestation(store: Store, validator: Validator) -> Attestation` be the attestation with the highest slot number in `store` from `validator`. If several such attestations exist, use the one the [validator](#dfn-validator) `v` observed first.
* Let `get_latest_attestation_target(store: Store, validator: Validator) -> BeaconBlock` be the target block in the attestation `get_latest_attestation(store, validator)`.
* Let `get_latest_attestation(store: Store, validator_index: ValidatorIndex) -> Attestation` be the attestation with the highest slot number in `store` from the validator with the given `validator_index`. If several such attestations exist, use the one the [validator](#dfn-validator) `v` observed first.
* Let `get_latest_attestation_target(store: Store, validator_index: ValidatorIndex) -> BeaconBlock` be the target block in the attestation `get_latest_attestation(store, validator_index)`.
* Let `get_children(store: Store, block: BeaconBlock) -> List[BeaconBlock]` returns the child blocks of the given `block`.
* Let `justified_head_state` be the resulting `BeaconState` object from processing the chain up to the `justified_head`.
* The `head` is `lmd_ghost(store, justified_head_state, justified_head)` where the function `lmd_ghost` is defined below. Note that the implementation below is suboptimal; there are implementations that compute the head in time logarithmic in slot count.
@ -1567,21 +1574,18 @@ def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock)
Execute the LMD-GHOST algorithm to find the head ``BeaconBlock``.
"""
validators = start_state.validator_registry
active_validators = [
validators[i]
for i in get_active_validator_indices(validators, start_state.slot)
]
active_validator_indices = get_active_validator_indices(validators, start_state.slot)
attestation_targets = [
get_latest_attestation_target(store, validator)
for validator in active_validators
(validator_index, get_latest_attestation_target(store, validator_index))
for validator_index in active_validator_indices
]
def get_vote_count(block: BeaconBlock) -> int:
return len([
target
for target in attestation_targets
return sum(
get_effective_balance(start_state.validator_balances[validator_index]) // FORK_CHOICE_BALANCE_INCREMENT
for validator_index, target in attestation_targets
if get_ancestor(store, target, block.slot) == block
])
)
head = start_block
while 1: