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https://github.com/0glabs/0g-chain.git
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ee61e39769
calc inflation based on staking apy
77 lines
2.4 KiB
Go
77 lines
2.4 KiB
Go
package chaincfg
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import (
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"github.com/shopspring/decimal"
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sdk "github.com/cosmos/cosmos-sdk/types"
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minttypes "github.com/cosmos/cosmos-sdk/x/mint/types"
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)
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var (
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Xmax, _ = sdk.NewDecFromStr("1.0") // upper limit on staked supply (as % of circ supply)
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Ymin, _ = sdk.NewDecFromStr("0.05") // target APY at upper limit
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Xmin, _ = sdk.NewDecFromStr("0.2") // lower limit on staked supply (as % of circ supply)
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Ymax, _ = sdk.NewDecFromStr("0.15") // target APY at lower limit
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decayRate, _ = sdk.NewDecFromStr("10")
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)
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func decExp(x sdk.Dec) sdk.Dec {
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xDec := decimal.NewFromBigInt(x.BigInt(), -18)
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expDec, _ := xDec.ExpTaylor(18)
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expInt := expDec.Shift(18).BigInt()
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return sdk.NewDecFromBigIntWithPrec(expInt, 18)
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}
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func NextInflationRate(ctx sdk.Context, minter minttypes.Minter, params minttypes.Params, bondedRatio sdk.Dec, circulatingRatio sdk.Dec) sdk.Dec {
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X := bondedRatio.Quo(circulatingRatio)
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var apy sdk.Dec
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if X.LT(Xmin) {
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apy = Ymax
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} else {
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exp := decayRate.Neg().Mul(Xmax.Sub(Xmin))
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c := decExp(exp)
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d := Ymin.Sub(Ymax.Mul(c)).Quo(sdk.OneDec().Sub(c))
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expBonded := decayRate.Neg().Mul(X.Sub(Xmin))
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cBonded := decExp(expBonded)
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e := Ymax.Sub(d).Mul(cBonded)
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apy = d.Add(e)
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}
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inflation := apy.Mul(bondedRatio)
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// // The target annual inflation rate is recalculated for each previsions cycle. The
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// // inflation is also subject to a rate change (positive or negative) depending on
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// // the distance from the desired ratio (67%). The maximum rate change possible is
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// // defined to be 13% per year, however the annual inflation is capped as between
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// // 7% and 20%.
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// // (1 - bondedRatio/GoalBonded) * InflationRateChange
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// inflationRateChangePerYear := sdk.OneDec().
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// Sub(bondedRatio.Quo(params.GoalBonded)).
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// Mul(params.InflationRateChange)
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// inflationRateChange := inflationRateChangePerYear.Quo(sdk.NewDec(int64(params.BlocksPerYear)))
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// // adjust the new annual inflation for this next cycle
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// inflation := minter.Inflation.Add(inflationRateChange) // note inflationRateChange may be negative
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// if inflation.GT(params.InflationMax) {
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// inflation = params.InflationMax
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// }
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// if inflation.LT(params.InflationMin) {
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// inflation = params.InflationMin
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// }
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ctx.Logger().Info(
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"nextInflationRate",
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"bondedRatio", bondedRatio,
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"circulatingRatio", circulatingRatio,
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"apy", apy,
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"inflation", inflation,
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"params", params,
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"minter", minter,
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)
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return inflation
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}
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