# IDragonswapV2PoolDerivedState

Contains view functions to provide information about the pool that is computed rather than stored on the blockchain. The functions here may have variable gas costs.

### Functions[​](https://docs.uniswap.org/contracts/v3/reference/core/interfaces/pool/IUniswapV3PoolDerivedState#functions) <a href="#functions" id="functions"></a>

#### observe[​](https://docs.uniswap.org/contracts/v3/reference/core/interfaces/pool/IUniswapV3PoolDerivedState#observe) <a href="#observe" id="observe"></a>

```solidity
  function observe(
    uint32[] secondsAgos
  ) external view returns (int56[] tickCumulatives, uint160[] secondsPerLiquidityCumulativeX128s)
```

Returns the cumulative tick and liquidity as of each timestamp `secondsAgo` from the current block timestamp

To get a time weighted average tick or liquidity-in-range, you must call this with two values, one representing the beginning of the period and another for the end of the period. E.g., to get the last hour time-weighted average tick, you must call it with secondsAgos = \[3600, 0]. The time weighted average tick represents the geometric time weighted average price of the pool, in log base sqrt(1.0001) of token1 / token0. The TickMath library can be used to go from a tick value to a ratio.

**Parameters:**[**​**](https://docs.uniswap.org/contracts/v3/reference/core/interfaces/pool/IUniswapV3PoolDerivedState#parameters)

| Name          | Type      | Description                                                                   |
| ------------- | --------- | ----------------------------------------------------------------------------- |
| `secondsAgos` | uint32\[] | From how long ago each cumulative tick and liquidity value should be returned |

**Return Values:**[**​**](https://docs.uniswap.org/contracts/v3/reference/core/interfaces/pool/IUniswapV3PoolDerivedState#return-values)

| Name                                 | Type       | Description                                                                                     |
| ------------------------------------ | ---------- | ----------------------------------------------------------------------------------------------- |
| `tickCumulatives`                    | int56\[]   | Cumulative tick values as of each `secondsAgos` from the current block timestamp                |
| `secondsPerLiquidityCumulativeX128s` | uint160\[] | Cumulative seconds per liquidity-in-range value as of each `secondsAgos` from the current block |

timestamp

#### snapshotCumulativesInside[​](https://docs.uniswap.org/contracts/v3/reference/core/interfaces/pool/IUniswapV3PoolDerivedState#snapshotcumulativesinside) <a href="#snapshotcumulativesinside" id="snapshotcumulativesinside"></a>

```solidity
  function snapshotCumulativesInside(
    int24 tickLower,
    int24 tickUpper
  ) external returns (int56 tickCumulativeInside, uint160 secondsPerLiquidityInsideX128, uint32 secondsInside)
```

Returns a snapshot of the tick cumulative, seconds per liquidity and seconds inside a tick range

Snapshots must only be compared to other snapshots, taken over a period for which a position existed. I.e., snapshots cannot be compared if a position is not held for the entire period between when the first snapshot is taken and the second snapshot is taken.

**Parameters:**[**​**](https://docs.uniswap.org/contracts/v3/reference/core/interfaces/pool/IUniswapV3PoolDerivedState#parameters-1)

| Name        | Type  | Description                 |
| ----------- | ----- | --------------------------- |
| `tickLower` | int24 | The lower tick of the range |
| `tickUpper` | int24 | The upper tick of the range |

**Return Values:**[**​**](https://docs.uniswap.org/contracts/v3/reference/core/interfaces/pool/IUniswapV3PoolDerivedState#return-values-1)

| Name                            | Type    | Description                                         |
| ------------------------------- | ------- | --------------------------------------------------- |
| `tickCumulativeInside`          | int56   | The snapshot of the tick accumulator for the range  |
| `secondsPerLiquidityInsideX128` | uint160 | The snapshot of seconds per liquidity for the range |
| `secondsInside`                 | uint32  | The snapshot of seconds per liquidity for the range |