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

Merge pull request #565 from terenc3t/patch-45 

get_previous_epoch as a helper
This commit is contained in:
Hsiao-Wei Wang 2019-02-04 14:56:15 +08:00 committed by GitHub
parent 3aed1cf935 3a6da9839a
commit 47844116ea
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 16 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
specs/core/0_beacon-chain.md
View File

@ -54,6 +54,7 @@
- [`hash`](#hash)
- [`hash_tree_root`](#hash_tree_root)
- [`slot_to_epoch`](#slot_to_epoch)
- [`get_previous_epoch`](#get_previous_epoch)
- [`get_current_epoch`](#get_current_epoch)
- [`get_epoch_start_slot`](#get_epoch_start_slot)
- [`is_active_validator`](#is_active_validator)
@ -640,6 +641,19 @@ def slot_to_epoch(slot: SlotNumber) -> EpochNumber:
return slot // EPOCH_LENGTH
```
### `get_previous_epoch`
```python
def get_previous_epoch(state: BeaconState) -> EpochNumber:
"""`
Return the previous epoch of the given ``state``.
If the current epoch is ``GENESIS_EPOCH``, return ``GENESIS_EPOCH``.
"""
if slot_to_epoch(state.slot) > GENESIS_EPOCH:
return slot_to_epoch(state.slot) - 1
return slot_to_epoch(state.slot)
```
### `get_current_epoch`
```python
@ -845,7 +859,7 @@ def get_crosslink_committees_at_slot(state: BeaconState,
"""
epoch = slot_to_epoch(slot)
current_epoch = get_current_epoch(state)
previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else current_epoch
previous_epoch = get_previous_epoch(state)
next_epoch = current_epoch + 1
assert previous_epoch <= epoch <= next_epoch
@ -1767,7 +1781,7 @@ The steps below happen when `(state.slot + 1) % EPOCH_LENGTH == 0`.
#### Helpers
* Let `current_epoch = get_current_epoch(state)`.
* Let `previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else current_epoch`.
* Let `previous_epoch = get_previous_epoch(state)`.
* Let `next_epoch = current_epoch + 1`.
[Validators](#dfn-Validator) attesting during the current epoch: