Get Elastic Pool Price

Query Historical Price Data

Overview

KyberSwap Elastic enables integrators to trustlessly query the time-weighted average price of an Elastic pool via the poolOracle contract. Integrators can then derive the geometric mean to get an accurate representation of the pool's price data. For more information on the variable definitions, concepts, and implementation details, please refer to TWAP Oracle.

Elastic SDK

KyberSwap has created an Elastic SDK to make interacting with our Elastic smart contracts easier. You can refer to our Elastic SDK Developer Guides for step-by-step walkthroughs on how to achieve various Elastic operations in a TypeScript environment.

Getting the pool price

Retrieve the accumulated tick

To compute the TWAP, we first need to retrieve the tick accumulator for the requested time period. The poolOracle contract exposes an observeFromPool() function which expects:

• pool: The address of the pool whose price is being queried

• secondsAgo: A list of the amount of time, in seconds, since the query at which to return the tickCumulative value.

Note that a secondsAgo value of 0 or a value later than the last observation will return the latest tickCumulative value. If the target time matches an observation timestamp, the corresponding tickCumulative of the observation will be returned. If the target time is between two observations, the interpolated tickCumulative of the two observations will be returned.

Calculating the geometric mean TWAP

Following the query above, we can then extract the average price by using this formula:

$$\begin{align*} p_{(t_1, t_2)}&=(\prod_{i=t_1}^{t_2} p_i)^\frac{1}{t_2-t_1} \\ &=(\prod_{i=t_1}^{t_2} 1.0001^{log_{1.0001} p_i})^\frac{1}{t_2-t_1} \\ &\approx 1.0001^{{\sum_{i=t_1}^{t_2}tick_i}\frac{1}{t_2-t_1}} \\ &= 1.0001^{\frac{a_{t_2}-a_{t_1}}{t_2-t_1}} \end{align*}$$

Assumptions

• We are querying a WETH/USDT pool to get the average price for the pool over the last hour

• Using a secondsAgo of [0, 3600], the observeFromPool() function above returns a tickCumulatives value of [500000000, 225000000].

Calculation

Plugging in the values, we get:

$$p_{(t_1, t_2)}= 1.0001^{\frac{a_{t_2}-a_{t_1}}{t_2-t_1}}$$

$$p_{(t_1, t_2)}= 1.0001^{\frac{500,000,000-225,000,000}{3,600-0}}=1.0001^{76,389}=2,076.66 \text{USDC/WETH}$$