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Implement new difficulty calculation parameters.

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This commit is contained in:
Julian Yap 2017-01-31 20:20:13 -10:00
parent 28a2fc3736
commit 55ddf3df43
1 changed files with 112 additions and 2 deletions
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114
core/block_validator.go
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@ -32,12 +32,16 @@ import (
)
var (
ExpDiffPeriod = big.NewInt(100000)
big88 = big.NewInt(88)
bigMinus99 = big.NewInt(-99)
nPowAveragingWindow = big.NewInt(21)
nPowMaxAdjustDown = big.NewInt(16) // 16% adjustment down
nPowMaxAdjustUp = big.NewInt(8) // 8% adjustment up
diffChangeBlock = big.NewInt(4088)
nPowAveragingWindow2 = big.NewInt(88)
nPowMaxAdjustDown2 = big.NewInt(3) // 3% adjustment down
nPowMaxAdjustUp2 = big.NewInt(2) // 2% adjustment up
)
func AveragingWindowTimespan() *big.Int {
@ -67,6 +71,31 @@ func MaxActualTimespan() *big.Int {
return z
}
func AveragingWindowTimespan2() *big.Int {
x := new(big.Int)
return x.Mul(nPowAveragingWindow2, big88)
}
func MinActualTimespan2() *big.Int {
x := new(big.Int)
y := new(big.Int)
z := new(big.Int)
x.Sub(big.NewInt(100), nPowMaxAdjustUp2)
y.Mul(AveragingWindowTimespan2(), x)
z.Div(y, big.NewInt(100))
return z
}
func MaxActualTimespan2() *big.Int {
x := new(big.Int)
y := new(big.Int)
z := new(big.Int)
x.Add(big.NewInt(100), nPowMaxAdjustDown2)
y.Mul(AveragingWindowTimespan2(), x)
z.Div(y, big.NewInt(100))
return z
}
// BlockValidator is responsible for validating block headers, uncles and
// processed state.
//
@ -338,11 +367,19 @@ func ValidateHeaderHeaderChain(config *params.ChainConfig, pow pow.PoW, header *
return nil
}
func CalcDifficulty(config *params.ChainConfig, time, parentTime uint64, parentNumber, parentDiff *big.Int, bc *BlockChain) *big.Int {
if parentNumber.Cmp(diffChangeBlock) < 0 {
return CalcDifficultyOrig(time, parentTime, parentNumber, parentDiff, bc)
} else {
return CalcDifficulty2(time, parentTime, parentNumber, parentDiff, bc)
}
}
// CalcDifficulty is the difficulty adjustment algorithm. It returns
// the difficulty that a new block should have when created at time
// given the parent block's time and difficulty.
// Rewritten to be based on Digibyte's Digishield v3 retargeting
func CalcDifficulty(config *params.ChainConfig, time, parentTime uint64, parentNumber, parentDiff *big.Int, bc *BlockChain) *big.Int {
func CalcDifficultyOrig(time, parentTime uint64, parentNumber, parentDiff *big.Int, bc *BlockChain) *big.Int {
// holds intermediate values to make the algo easier to read & audit
x := new(big.Int)
nFirstBlock := new(big.Int)
@ -398,7 +435,49 @@ func CalcDifficulty(config *params.ChainConfig, time, parentTime uint64, parentN
return x
}
func CalcDifficulty2(time, parentTime uint64, parentNumber, parentDiff *big.Int, bc *BlockChain) *big.Int {
x := new(big.Int)
nFirstBlock := new(big.Int)
nFirstBlock.Sub(parentNumber, nPowAveragingWindow2)
glog.V(logger.Debug).Infof("CalcDifficulty2 parentNumber: %v parentDiff: %v\n", parentNumber, parentDiff)
nLastBlockTime := bc.CalcPastMedianTime(parentNumber.Uint64())
nFirstBlockTime := bc.CalcPastMedianTime(nFirstBlock.Uint64())
nActualTimespan := new(big.Int)
nActualTimespan.Sub(nLastBlockTime, nFirstBlockTime)
y := new(big.Int)
y.Sub(nActualTimespan, AveragingWindowTimespan2())
y.Div(y, big.NewInt(4))
nActualTimespan.Add(y, AveragingWindowTimespan2())
if nActualTimespan.Cmp(MinActualTimespan2()) < 0 {
nActualTimespan.Set(MinActualTimespan2())
} else if nActualTimespan.Cmp(MaxActualTimespan2()) > 0 {
nActualTimespan.Set(MaxActualTimespan2())
}
x.Mul(parentDiff, AveragingWindowTimespan2())
x.Div(x, nActualTimespan)
if x.Cmp(params.MinimumDifficulty) < 0 {
x.Set(params.MinimumDifficulty)
}
return x
}
func CalcDifficultyHeaderChain(config *params.ChainConfig, time, parentTime uint64, parentNumber, parentDiff *big.Int, hc *HeaderChain) *big.Int {
if parentNumber.Cmp(diffChangeBlock) < 0 {
return CalcDifficultyHeaderChainOrig(time, parentTime, parentNumber, parentDiff, hc)
} else {
return CalcDifficultyHeaderChain2(time, parentTime, parentNumber, parentDiff, hc)
}
}
func CalcDifficultyHeaderChainOrig(time, parentTime uint64, parentNumber, parentDiff *big.Int, hc *HeaderChain) *big.Int {
// holds intermediate values to make the algo easier to read & audit
x := new(big.Int)
nFirstBlock := new(big.Int)
@ -438,6 +517,37 @@ func CalcDifficultyHeaderChain(config *params.ChainConfig, time, parentTime uint
return x
}
func CalcDifficultyHeaderChain2(time, parentTime uint64, parentNumber, parentDiff *big.Int, hc *HeaderChain) *big.Int {
x := new(big.Int)
nFirstBlock := new(big.Int)
nFirstBlock.Sub(parentNumber, nPowAveragingWindow2)
nLastBlockTime := hc.CalcPastMedianTime(parentNumber.Uint64())
nFirstBlockTime := hc.CalcPastMedianTime(nFirstBlock.Uint64())
nActualTimespan := new(big.Int)
nActualTimespan.Sub(nLastBlockTime, nFirstBlockTime)
y := new(big.Int)
y.Sub(nActualTimespan, AveragingWindowTimespan2())
y.Div(y, big.NewInt(4))
nActualTimespan.Add(y, AveragingWindowTimespan2())
if nActualTimespan.Cmp(MinActualTimespan2()) < 0 {
nActualTimespan.Set(MinActualTimespan2())
} else if nActualTimespan.Cmp(MaxActualTimespan2()) > 0 {
nActualTimespan.Set(MaxActualTimespan2())
}
x.Mul(parentDiff, AveragingWindowTimespan2())
x.Div(x, nActualTimespan)
if x.Cmp(params.MinimumDifficulty) < 0 {
x.Set(params.MinimumDifficulty)
}
return x
}
func CalcDifficultyLegacy(config *params.ChainConfig, time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
bigTime := new(big.Int).SetUint64(time)
bigParentTime := new(big.Int).SetUint64(parentTime)