This is an attempt at implementing the logic BIP8, in particular to check whether allowing some MUST_SIGNAL blocks to not signal (PR #1021 has the desired effect.
Running ./tests.sh should quickcheck that the following properties hold for a large number of chains:
- if the chain is valid under
{ lot = true, timeout = T }, it's valid under{ lot = false, timeout >= T } - if the chain is valid under
{ lot = false, timeout = T }and the bip8 state is LockedIn or Active, it's valid under{ lot = true, timeout = T }
Note that only property 2. wouldn't hold without PR #1021).
Quick & dirty simulation of impact of threshold parameters
$ python ./threshold.py
Probability that unupdated node is on >= 2 block invalid fork with 95.0% threshold: 1.22%
Probability that unupdated node is on >= 3 block invalid fork with 95.0% threshold: 0.17%
Probability that unupdated node is on >= 2 block invalid fork with 90.0% threshold: 4.81%
Probability that unupdated node is on >= 3 block invalid fork with 90.0% threshold: 1.28%
Probability that unupdated node is on >= 2 block invalid fork with 85.0% threshold: 10.45%
Probability that unupdated node is on >= 3 block invalid fork with 85.0% threshold: 4.13%
https://gist.github.com/ajtowns/fbcf30ed9d0e1708fdc98a876a04ff69#file-repeated_trials-py