INCORRECTLY calculate the Zcash supply after a given block height on Mainnet or Testnet (not taking into account the slow start)
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#!/usr/bin/env python3 | |
# ***INCORRECT VERSION, FOR ILLUSTRATION ONLY*** | |
def exact_div(x, y): | |
assert x % y == 0 | |
return x // y | |
# floor(u/x + v/y) | |
def div2(u, x, v, y): | |
return (u*y + v*x) // (x*y) | |
TESTNET = 0 | |
MAINNET = 1 | |
class Network: | |
# <https://zips.z.cash/protocol/protocol.pdf#constants> | |
def __init__(self, network): | |
self.BlossomActivationHeight = 653600 if network == MAINNET else 584000 | |
SlowStartInterval = 20000 | |
MaxBlockSubsidy = 1250000000 # 12.5 ZEC | |
PreBlossomHalvingInterval = 840000 | |
PreBlossomPoWTargetSpacing = 150 | |
PostBlossomPoWTargetSpacing = 75 | |
# <https://zips.z.cash/protocol/protocol.pdf#diffadjustment> | |
def IsBlossomActivated(self, height): | |
return height >= self.BlossomActivationHeight | |
BlossomPoWTargetSpacingRatio = exact_div(PreBlossomPoWTargetSpacing, PostBlossomPoWTargetSpacing) | |
# no need for floor since this is necessarily an integer | |
PostBlossomHalvingInterval = PreBlossomHalvingInterval * BlossomPoWTargetSpacingRatio | |
# <https://zips.z.cash/protocol/protocol.pdf#subsidies> | |
SlowStartShift = exact_div(SlowStartInterval, 2) | |
SlowStartRate = exact_div(MaxBlockSubsidy, SlowStartInterval) | |
def Halving(self, height): | |
if height < self.SlowStartShift: | |
return 0 | |
elif not self.IsBlossomActivated(height): | |
return (height - self.SlowStartShift) // self.PreBlossomHalvingInterval | |
else: | |
return div2(self.BlossomActivationHeight - self.SlowStartShift, self.PreBlossomHalvingInterval, | |
height - self.BlossomActivationHeight, self.PostBlossomHalvingInterval) | |
def BlockSubsidy(self, height): | |
#if height < self.SlowStartShift: | |
# return self.SlowStartRate * height | |
#elif self.SlowStartShift <= height and height < self.SlowStartInterval: | |
# return self.SlowStartRate * (height + 1) | |
#if self.SlowStartInterval <= height and not self.IsBlossomActivated(height): | |
# THIS IS WRONG: it does not take into account the slow start | |
if not self.IsBlossomActivated(height): | |
return self.MaxBlockSubsidy // (1 << self.Halving(height)) | |
else: | |
return self.MaxBlockSubsidy // (self.BlossomPoWTargetSpacingRatio << self.Halving(height)) | |
def SupplyAfterHeight(self, height): | |
return sum((self.BlockSubsidy(h) for h in range(height+1))) | |
# WRONG VALUES (NO SLOW START) | |
print(Network(MAINNET).SupplyAfterHeight(1799152)) # September 6th 2022 12:15 UTC | |
print(Network(MAINNET).SupplyAfterHeight(1875375)) # November 11th 2022 11:35 UTC |
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