from unittest import TestCase import numpy as np from .cryptarchia import ( Leader, Config, EpochState, LedgerState, Coin, phi, TimeConfig, Slot, ) from .test_common import mk_config class TestLeader(TestCase): def test_slot_leader_statistics(self): epoch = EpochState( stake_distribution_snapshot=LedgerState(), nonce_snapshot=LedgerState(nonce=b"1010101010"), inferred_total_active_stake=1000, ) coin = Coin(sk=0, value=10) f = 0.05 l = Leader( config=mk_config([coin]).replace(active_slot_coeff=f), coin=coin, ) # We'll use the Margin of Error equation to decide how many samples we need. # https://en.wikipedia.org/wiki/Margin_of_error margin_of_error = 1e-4 p = phi(f=f, alpha=10 / epoch.total_active_stake()) std = np.sqrt(p * (1 - p)) Z = 3 # we want 3 std from the mean to be within the margin of error N = int((Z * std / margin_of_error) ** 2) # After N slots, the measured leader rate should be within the # interval `p +- margin_of_error` with high probabiltiy leader_rate = ( sum( l.try_prove_slot_leader(epoch, Slot(slot), bytes(32)) is not None for slot in range(N) ) / N ) assert ( abs(leader_rate - p) < margin_of_error ), f"{leader_rate} != {p}, err={abs(leader_rate - p)} > {margin_of_error}"