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Finish draft of AMM tutorial

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mDuo13
2024-05-07 19:10:07 -07:00
parent 46d1add256
commit 8b687e98ea
2 changed files with 169 additions and 77 deletions
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103
_code-samples/auction-slot/js/auction-slot.js
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@@ -1,8 +1,7 @@
const xrpl = require('xrpl')
const BigNumber = require('bignumber.js')
/*
* Convert a trading fee to a value that can be multiplied
/* Convert a trading fee to a value that can be multiplied
* by a total to "subtract" the fee from the total.
* @param tFee int {0, 1000}
* such that 1 = 1/100,000 and 1000 = 1% fee
@@ -12,8 +11,7 @@ function feeMult(tFee) {
return BigNumber(1).minus( feeDecimal(tFee) )
}
/*
* Same as feeMult, but with half the trading fee.
/* Same as feeMult, but with half the trading fee.
* @param tFee int {0, 1000}
* such that 1 = 1/100,000 and 1000 = 1% fee
* @returns BigNumber (1 - (fee/2)) as a decimal
@@ -22,8 +20,7 @@ function feeMultHalf(tFee) {
return BigNumber(1).minus( feeDecimal(tFee).dividedBy(2) )
}
/*
* Convert a trading fee to a decimal BigNumber value,
/* Convert a trading fee to a decimal BigNumber value,
* for example 1000 becomes 0.01
* @param tFee int {0, 1000}
* such that 1 = 1/100,000 and 1000 = 1% fee
@@ -34,8 +31,7 @@ function feeDecimal(tFee) {
return BigNumber(tFee).dividedBy(AUCTION_SLOT_FEE_SCALE_FACTOR)
}
/*
* Implements the AMM SwapOut formula, as defined in XLS-30 section 2.4 AMM
/* Implement the AMM SwapOut formula, as defined in XLS-30 section 2.4 AMM
* Swap, formula 10. The asset weights WA/WB are currently always 1/1 so
* they're canceled out.
* C++ source: https://github.com/XRPLF/rippled/blob/2d1854f354ff8bb2b5671fd51252c5acd837c433/src/ripple/app/misc/AMMHelpers.h#L253-L258
@@ -60,8 +56,7 @@ function swapOut(asset_out_bn, pool_in_bn, pool_out_bn, trading_fee) {
).dividedBy(feeMult(trading_fee))
}
/*
* Computes the quadratic formula. Helper function for ammAssetIn.
/* Compute the quadratic formula. Helper function for ammAssetIn.
* Params and return value are BigNumber instances.
*/
function solveQuadraticEq(a,b,c) {
@@ -71,8 +66,7 @@ function solveQuadraticEq(a,b,c) {
return ( b.negated().plus(b2minus4ac.sqrt()) ).dividedBy(a.multipliedBy(2))
}
/*
* Implements the AMM single-asset deposit formula to calculate how much to
/* Implement the AMM single-asset deposit formula to calculate how much to
* put in so that you receive a specific number of LP Tokens back.
* C++ source: https://github.com/XRPLF/rippled/blob/2d1854f354ff8bb2b5671fd51252c5acd837c433/src/ripple/app/misc/impl/AMMHelpers.cpp#L55-L83
* @param pool_in string - Quantity of input asset the pool already has
@@ -100,38 +94,7 @@ function ammAssetIn(pool_in, lpt_balance, desired_lpt, trading_fee) {
return asset1Balance.multipliedBy(solveQuadraticEq(a,b,c))
}
/*
* Calculates the necessary bid to win the AMM Auction slot, per the pricing
* algorithm defined in XLS-30 section 4.1.1, if you already hold LP Tokens.
* Not useful in the case where you need to make a deposit to get LP Tokens,
* because doing so causes more LP Tokens to be issued, changing the min bid.
* @returns BigNumber - the minimum amount of LP tokens to win the auction slot
*/
function auctionPrice(old_bid, time_interval, trading_fee, lpt_balance) {
const tfee_decimal = feeDecimal(trading_fee)
const lptokens = BigNumber(lpt_balance)
const min_bid = lptokens.multipliedBy(tfee_decimal).dividedBy(25)
const b = BigNumber(old_bid)
let new_bid = min_bid
if (time_interval == 0) {
new_bid = b.multipliedBy("1.05").plus(min_bid)
} else if (time_interval <= 19) {
const t60 = BigNumber(time_interval).multipliedBy("0.05"
).exponentiatedBy(60)
new_bid = b.multipliedBy("1.05").multipliedBy(
BigNumber(1).minus(t60)
).plus(min_bid)
}
const rounded_bid = new_bid.plus(lptokens).precision(15, BigNumber.CEILING
).minus(lptokens).precision(15, BigNumber.FLOOR)
return rounded_bid
}
/*
* Calculates how much to deposit, in terms of LP Tokens out, to be able to win
/* Calculate how much to deposit, in terms of LP Tokens out, to be able to win
* the auction slot. This is based on the slot pricing algorithm defined in
* XLS-30 section 4.1.1, but factors in the increase in the minimum bid as a
* result of having new LP Tokens issued to you from your deposit.
@@ -173,7 +136,7 @@ async function main() {
const wallet = (await client.fundWallet()).wallet
console.log(`Got address ${wallet.address} / seed ${wallet.seed}.`)
// Look up the AMM
// Look up AMM status -----------------------------------------------------
const from_asset = {
"currency": "XRP"
}
@@ -242,21 +205,12 @@ async function main() {
console.log(`Potential savings: ${xrpl.dropsToXrp(potential_savings)} XRP`)
// Calculate the cost of winning the auction slot, in LP Tokens -----------
// The price is slightly different if you already hold LP Tokens vs if you
// have to make a deposit, because the deposit causes more LP Tokens to be
// issued, which increases the minimum bid.
const lp_auction_price = auctionPrice(old_bid, time_interval,
full_trading_fee, lpt.value
).precision(15)
console.log(`Auction price for current LPs: ${lp_auction_price} LP Tokens`)
const auction_price = auctionDeposit(old_bid, time_interval,
full_trading_fee, lpt.value
).precision(15)
console.log(`Auction price after deposit: ${auction_price} LP Tokens`)
// Calculate how much XRP to deposit to receive that many LP Tokens
// Calculate how much XRP to deposit to receive that many LP Tokens -------
const deposit_for_bid = ammAssetIn(pool_in_bn, lpt.value, auction_price,
full_trading_fee
).dp(0, BigNumber.ROUND_CEIL)
@@ -337,3 +291,42 @@ async function main() {
} // End of main()
main()
/// TODO: move everything below here to a separate code sample with minimal setup to make it work:
// /* Calculate the necessary bid to win the AMM Auction slot, per the pricing
// * algorithm defined in XLS-30 section 4.1.1, if you already hold LP Tokens.
// * Not useful in the case where you need to make a deposit to get LP Tokens,
// * because doing so causes more LP Tokens to be issued, changing the min bid.
// * @returns BigNumber - the minimum amount of LP tokens to win the auction slot
// */
// function auctionPrice(old_bid, time_interval, trading_fee, lpt_balance) {
// const tfee_decimal = feeDecimal(trading_fee)
// const lptokens = BigNumber(lpt_balance)
// const min_bid = lptokens.multipliedBy(tfee_decimal).dividedBy(25)
// const b = BigNumber(old_bid)
// let new_bid = min_bid
// if (time_interval == 0) {
// new_bid = b.multipliedBy("1.05").plus(min_bid)
// } else if (time_interval <= 19) {
// const t60 = BigNumber(time_interval).multipliedBy("0.05"
// ).exponentiatedBy(60)
// new_bid = b.multipliedBy("1.05").multipliedBy(
// BigNumber(1).minus(t60)
// ).plus(min_bid)
// }
// const rounded_bid = new_bid.plus(lptokens).precision(15, BigNumber.CEILING
// ).minus(lptokens).precision(15, BigNumber.FLOOR)
// return rounded_bid
// }
//
//
// // The price is slightly different if you already hold LP Tokens vs if you
// // have to make a deposit, because the deposit causes more LP Tokens to be
// // issued, which increases the minimum bid.
// const lp_auction_price = auctionPrice(old_bid, time_interval,
// full_trading_fee, lpt.value
// ).precision(15)
// console.log(`Auction price for current LPs: ${lp_auction_price} LP Tokens`)