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library.Calculate.md

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Calculate

Git Source

Author: Anton Davydov

Functions

removeLiquidity

Calculate amount of liquidity tokens that should be removed from the pool to reach minimum reserve value

function removeLiquidity(uint256 reserve, uint256 minimum, uint256 availableLiquidity, uint256 totalSupply)
    internal
    pure
    returns (uint256 leftoverLiquidity, uint256 removedLiquidity);

Parameters

Name Type Description
reserve uint256 The size of token reserve in the pool
minimum uint256 The size of token reserve after liquidity removal
availableLiquidity uint256 The amount of owned liquidity provider tokens
totalSupply uint256 Total amount of liquidity provider tokens

Returns

Name Type Description
leftoverLiquidity uint256 Amount of liquidity tokens left after removal
removedLiquidity uint256 Amount of liquidity tokens to remove

swapToRatio

Calculate amount of tokens that will be swapped

function swapToRatio(
    uint256 reserveBase,
    uint256 reserveQuote,
    uint256 targetBase,
    uint256 targetQuote,
    uint256 feeNumerator,
    uint256 feeDenominator
) internal pure returns (bool baseToQuote, uint256 amountIn, uint256 amountOut);

Parameters

Name Type Description
reserveBase uint256 The size of base token reserve in the pool
reserveQuote uint256 The size of quote token reserve in the pool
targetBase uint256 The number of base parts in target ratio
targetQuote uint256 The number of quote parts in target ratio
feeNumerator uint256 The top of a fraction that represents swap size minus fees
feeDenominator uint256 The bottom of a fraction that represents swap size minus fees

Returns

Name Type Description
baseToQuote bool Whether to sell base and buy quote, or vice versa, trading direction
amountIn uint256 The amount of tokens that will be sold
amountOut uint256 The amount of tokens that will be bought

addLiquidity

Calculate the size of token liquidity required to reach invariant base reserve

function addLiquidity(uint256 reserveBase, uint256 reserveQuote, uint256 reserveBaseInvariant)
    internal
    pure
    returns (uint256 amountBaseDesired, uint256 amountQuoteOptimal);

Parameters

Name Type Description
reserveBase uint256 The size of base token reserve in the pool
reserveQuote uint256 The size of quote token reserve in the pool
reserveBaseInvariant uint256 The target size of base reserve

Returns

Name Type Description
amountBaseDesired uint256 Required amount of base tokens
amountQuoteOptimal uint256 Required amount of quote tokens

checkPrecision

Check if the difference between pool and target ratios is smaller than acceptable margin of error

function checkPrecision(
    uint256 reserveBase,
    uint256 reserveQuote,
    uint256 targetBase,
    uint256 targetQuote,
    uint256 precisionNumerator,
    uint256 precisionDenominator
) internal pure returns (bool);

Parameters

Name Type Description
reserveBase uint256 The size of base token reserve in the pool
reserveQuote uint256 The size of quote token reserve in the pool
targetBase uint256 The number of base parts in target ratio
targetQuote uint256 The number of quote parts in target ratio
precisionNumerator uint256 The top of a fraction that represents the acceptable margin of error
precisionDenominator uint256 The bottom of a fraction that represents the acceptable margin of error

Returns

Name Type Description
<none> bool isPrecise Difference between ratios is smaller than the acceptable margin of error

getAmountOut

Calculate the maximum output amount of the asset being bought

function getAmountOut(
    uint256 amountIn,
    uint256 reserveIn,
    uint256 reserveOut,
    uint256 feeNumerator,
    uint256 feeDenominator
) internal pure returns (uint256 amountOut);

Parameters

Name Type Description
amountIn uint256 The amount of tokens sold
reserveIn uint256 The reserve size of the token being sold
reserveOut uint256 The reserve size of the token being bought
feeNumerator uint256 The top of a fraction that represents swap size minus fees
feeDenominator uint256 The bottom of a fraction that represents swap size minus fees

Returns

Name Type Description
amountOut uint256 The amount of tokens bought