TwoKinksInterestRateModel

TwoKinksInterestRateModel

An interest rate model with two different slope increase or decrease each after a certain utilization threshold called kink is reached.

Solidity API

MULTIPLIER_PER_BLOCK

The multiplier of utilization rate per block that gives the slope 1 of the interest rate scaled by EXP_SCALE

int256 MULTIPLIER_PER_BLOCK

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BASE_RATE_PER_BLOCK

The base interest rate per block which is the y-intercept when utilization rate is 0 scaled by EXP_SCALE

int256 BASE_RATE_PER_BLOCK

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KINK_1

The utilization point at which the multiplier2 is applied

int256 KINK_1

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MULTIPLIER_2_PER_BLOCK

The multiplier of utilization rate per block that gives the slope 2 of the interest rate scaled by EXP_SCALE

int256 MULTIPLIER_2_PER_BLOCK

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BASE_RATE_2_PER_BLOCK

The base interest rate per block which is the y-intercept when utilization rate hits KINK_1 scaled by EXP_SCALE

int256 BASE_RATE_2_PER_BLOCK

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RATE_1

The maximum kink interest rate scaled by EXP_SCALE

int256 RATE_1

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KINK_2

The utilization point at which the jump multiplier is applied

int256 KINK_2

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JUMP_MULTIPLIER_PER_BLOCK

The multiplier of utilization rate per block that gives the slope 3 of interest rate scaled by EXP_SCALE

int256 JUMP_MULTIPLIER_PER_BLOCK

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RATE_2

The maximum kink interest rate scaled by EXP_SCALE

int256 RATE_2

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constructor

Construct an interest rate model

constructor(int256 baseRatePerYear_, int256 multiplierPerYear_, int256 kink1_, int256 multiplier2PerYear_, int256 baseRate2PerYear_, int256 kink2_, int256 jumpMultiplierPerYear_) public

Parameters

Name	Type	Description
baseRatePerYear_	int256	The approximate target base APR, as a mantissa (scaled by EXP_SCALE)
multiplierPerYear_	int256	The rate of increase or decrease in interest rate wrt utilization (scaled by EXP_SCALE)
kink1_	int256	The utilization point at which the multiplier2 is applied
multiplier2PerYear_	int256	The rate of increase or decrease in interest rate wrt utilization after hitting KINK_1 (scaled by EXP_SCALE)
baseRate2PerYear_	int256	The additional base APR after hitting KINK_1, as a mantissa (scaled by EXP_SCALE)
kink2_	int256	The utilization point at which the jump multiplier is applied
jumpMultiplierPerYear_	int256	The multiplier after hitting KINK_2

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getBorrowRate

Calculates the current borrow rate per slot (block)

function getBorrowRate(uint256 cash, uint256 borrows, uint256 reserves) external view returns (uint256)

Parameters

Name	Type	Description
cash	uint256	The amount of cash in the market
borrows	uint256	The amount of borrows in the market
reserves	uint256	The amount of reserves in the market

Return Values

Name	Type	Description
[0]	uint256	The borrow rate percentage per slot (block) as a mantissa (scaled by EXP_SCALE)

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getSupplyRate

Calculates the current supply rate per slot (block)

function getSupplyRate(uint256 cash, uint256 borrows, uint256 reserves, uint256 reserveFactorMantissa) public view virtual returns (uint256)

Parameters

Name	Type	Description
cash	uint256	The amount of cash in the market
borrows	uint256	The amount of borrows in the market
reserves	uint256	The amount of reserves in the market
reserveFactorMantissa	uint256	The current reserve factor for the market

Return Values

Name	Type	Description
[0]	uint256	The supply rate percentage per slot (block) as a mantissa (scaled by EXP_SCALE)

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utilizationRate

Calculates the utilization rate of the market: borrows / (cash + borrows - reserves)

function utilizationRate(uint256 cash, uint256 borrows, uint256 reserves) public pure returns (uint256)

Parameters

Name	Type	Description
cash	uint256	The amount of cash in the market
borrows	uint256	The amount of borrows in the market
reserves	uint256	The amount of reserves in the market

Return Values

Name	Type	Description
[0]	uint256	The utilization rate as a mantissa between [0, EXP_SCALE]

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