Interest

JumpRateModelV4

Git Source

Inherits: IInterestRateModel, Ownable

Implementation of the IInterestRateModel interface for calculating interest rates

State Variables

blocksPerYear

The approximate number of blocks per year that is assumed by the interest rate model

uint256 public override blocksPerYear;

multiplierPerBlock

The multiplier of utilization rate that gives the slope of the interest rate

uint256 public override multiplierPerBlock;

baseRatePerBlock

The base interest rate which is the y-intercept when utilization rate is 0

uint256 public override baseRatePerBlock;

jumpMultiplierPerBlock

The multiplierPerBlock after hitting a specified utilization point

uint256 public override jumpMultiplierPerBlock;

kink

The utilization point at which the jump multiplier is applied

uint256 public override kink;

name

A name for user-friendliness, e.g. WBTC

string public override name;

Functions

constructor

Construct an interest rate model

constructor(
    uint256 blocksPerYear_,
    uint256 baseRatePerYear,
    uint256 multiplierPerYear,
    uint256 jumpMultiplierPerYear,
    uint256 kink_,
    address owner_,
    string memory name_
) Ownable(owner_);

Parameters

Name	Type	Description
blocksPerYear_	uint256	The estimated number of blocks per year
baseRatePerYear	uint256	The base APR, scaled by 1e18
multiplierPerYear	uint256	The rate increase in interest wrt utilization, scaled by 1e18
jumpMultiplierPerYear	uint256	The multiplier per block after utilization point
kink_	uint256	The utilization point where the jump multiplier applies
owner_	address	The owner of the contract
name_	string	A user-friendly name for the contract

updateJumpRateModel

Update the parameters of the interest rate model (only callable by owner, i.e. Timelock)

function updateJumpRateModel(
    uint256 baseRatePerYear,
    uint256 multiplierPerYear,
    uint256 jumpMultiplierPerYear,
    uint256 kink_
) external onlyOwner;

Parameters

Name	Type	Description
baseRatePerYear	uint256	The approximate target base APR, as a mantissa (scaled by 1e18)
multiplierPerYear	uint256	The rate of increase in interest rate wrt utilization (scaled by 1e18)
jumpMultiplierPerYear	uint256	The multiplierPerBlock after hitting a specified utilization point
kink_	uint256	The utilization point at which the jump multiplier is applied

updateBlocksPerYear

Updates the blocksPerYear in order to make interest calculations simpler

function updateBlocksPerYear(uint256 blocksPerYear_) external onlyOwner;

Parameters

Name	Type	Description
blocksPerYear_	uint256	The new estimated eth blocks per year.

isInterestRateModel

Should return true

function isInterestRateModel() external pure override returns (bool);

utilizationRate

Calculates the utilization rate of the market

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

Parameters

Name	Type	Description
cash	uint256	The total cash in the market
borrows	uint256	The total borrows in the market
reserves	uint256	The total reserves in the market

Returns

Name	Type	Description
<none>	uint256	The utilization rate as a mantissa between [0, 1e18]

getBorrowRate

Returns the current borrow rate per block for the market

function getBorrowRate(uint256 cash, uint256 borrows, uint256 reserves) public view override returns (uint256);

Parameters

Name	Type	Description
cash	uint256	The total cash in the market
borrows	uint256	The total borrows in the market
reserves	uint256	The total reserves in the market

Returns

Name	Type	Description
<none>	uint256	The current borrow rate per block, scaled by 1e18

getSupplyRate

Returns the current supply rate per block for the market

function getSupplyRate(uint256 cash, uint256 borrows, uint256 reserves, uint256 reserveFactorMantissa)
    external
    view
    override
    returns (uint256);

Parameters

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

Returns

Name	Type	Description
<none>	uint256	The current supply rate per block, scaled by 1e18

_updateJumpRateModel

Internal function to update the parameters of the interest rate model

function _updateJumpRateModel(
    uint256 baseRatePerYear,
    uint256 multiplierPerYear,
    uint256 jumpMultiplierPerYear,
    uint256 kink_
) private;

Parameters

Name	Type	Description
baseRatePerYear	uint256	The base APR, scaled by 1e18
multiplierPerYear	uint256	The rate increase wrt utilization, scaled by 1e18
jumpMultiplierPerYear	uint256	The multiplier per block after utilization point
kink_	uint256	The utilization point where the jump multiplier applies

Errors

JumpRateModelV4_MultiplierNotValid

error JumpRateModelV4_MultiplierNotValid();