dss-lerp

Performs linear interpolation over time on any Maker governance parameter. Normally this is performed out of the executive spell as you require auth permissions.

Usage

// Increase the global debt ceiling from 100M to 200M over 7 days
lerpFactory.newLerp("20210421_VOW_HUMP1", vat, "Line", block.timestamp, 100 * MILLION * RAD, 200 * MILLION * RAD, 7 days);

// Increase the ETH-A debt ceiling from 100M to 200M over 7 days
lerpFactory.newIlkLerp("20210421_VOW_HUMP2", vat, "ETH-A", "line", block.timestamp, 100 * MILLION * RAD, 200 * MILLION * RAD, 7 days);

Parameters

Each lerp factory invocation creates a new contract which has the following properties:

target - The contract which we are changing an administrative parameter. what - The name of the parameter. startTime - The starting time of this lerp instance. start - The starting value of that parameter. end - The ending value of that parameter. duration - How long this lerp is running for. done - Whether this lerp instance is finished or not.

Executing

The Lerp contract has one method to call, which is permissionless and can be called by anyone:

tick() - Updates the target parameter to be whatever value it should be at this moment in time. This will also finish off the lerp and set the parameter to the end value if the elapsed time is longer than the duration.

LerpFactory

The Lerp Factory (AKA LERP_FAB) provides a singleton inteface to keep track of all active lerp instances. It is deployed at the following addresses:

Latest

Mainnet: 0x9175561733d138326fdea86cdfdf53e92b588276 Goerli: 0xe7988b75a19d8690272d65882ab0d07d492f7002

Deprecated

Mainnet: 0x00B416da876fe42dd02813da435Cc030F0d72434 Kovan: 0xa6766Ed3574bAFc6114618E74035C7bb5e9a6aa9

You can get a list of all active lerp instances by calling list() which returns an array of addresses for active lerps. This list of active lerps is not in any particular order. Alternatively you can query for specific lerps (even ones that are no longer active) by calling lerps(bytes32) which returns the address of the lerp or address(0) if there isn't a match. For example, calling lerps("20210421_VOW_HUMP1") would return the first lerp from the example above.

To tick() all active lerps you can use the convenience function tall() short for "tick all".