> ## Documentation Index
> Fetch the complete documentation index at: https://docs.exponent.finance/llms.txt
> Use this file to discover all available pages before exploring further.

# LpFarm

> Onchain LpFarm account structure and fields

The LpFarm account manages liquidity mining rewards for a CLMM market. It tracks multiple emission tokens, their distribution rates, expiration timestamps, and the global emission index used to calculate rewards for LP positions.

## LpFarm

```rust theme={null}
pub struct LpFarm {
    /// Last timestamp when the farm was updated
    pub last_seen_timestamp: u32,

    /// Vector of farm emissions, one per reward token
    pub farm_emissions: Vec<FarmEmission>,
}
```

## FarmEmission

Individual emission token configuration and state.

```rust theme={null}
pub struct FarmEmission {
    /// Mint for the emission token
    pub mint: Pubkey,

    /// Rate at which the emission token is emitted per second
    pub token_rate: u64,

    /// Expiration timestamp for this emission
    pub expiry_timestamp: u32,

    /// Global index for converting LP shares into earned emissions
    /// This value increases over time as emissions accrue
    pub index: Number,
}
```

## Key Concepts

### Emission Mechanism

The LP farm distributes reward tokens to liquidity providers proportionally to their share of the total liquidity. Each `FarmEmission` represents a separate reward token stream.

The emission mechanism works as follows:

1. Emissions accrue at `token_rate` tokens per second
2. The global `index` increases based on emissions and total liquidity
3. Each LP position tracks its `last_seen_index` for each emission
4. Rewards owed = (current\_index - last\_seen\_index) × lp\_balance

### Token Rate and Duration

The `token_rate` field specifies how many tokens are distributed per second across all LPs. This rate combined with the `expiry_timestamp` determines the total emission budget:

```
total_emission_budget = token_rate × (expiry_timestamp - start_timestamp)
```

### Expiration Timestamp

The `expiry_timestamp` marks when this particular emission ends. After this time:

* The `index` stops increasing for this emission
* No new rewards accrue, but unclaimed rewards remain claimable
* The emission slot may be reused for a new reward program

### Global Index

The `index` field is a cumulative measure of emissions per unit of liquidity. It uses the `Number` type (Q64.64 fixed-point) to maintain precision despite division by large liquidity amounts.

Index updates occur during these operations:

* LP deposits (add liquidity)
* LP withdrawals (remove liquidity)
* Explicit farm update calls
* Emission claims

### Multiple Emissions

A single farm can run multiple emissions simultaneously via the `farm_emissions` vector. This allows markets to incentivize liquidity with multiple reward tokens (e.g., protocol token + partner token).

Each emission operates independently with its own:

* Reward token mint
* Emission rate
* Expiration timestamp
* Index tracking

### Farm Lifecycle

1. **Initialization** — Farm is created with initial emission configurations
2. **Active Emissions** — While `current_timestamp < expiry_timestamp`, emissions accrue at `token_rate`
3. **Index Updates** — The global `index` is updated whenever LPs interact with the market
4. **Expiration** — After `expiry_timestamp`, the emission stops accruing but remains claimable
5. **Renewal** — Expired emissions can be replaced with new emission configurations

### Last Seen Timestamp

The `last_seen_timestamp` tracks when the farm was last updated. This is used to calculate the time delta for index updates:

```
time_delta = current_timestamp - last_seen_timestamp
emission_accrued = time_delta × token_rate
index_increase = emission_accrued / total_liquidity
```

### Escrow Account Tracking

While not directly stored in the `LpFarm` struct, each emission requires a corresponding escrow token account owned by the market authority. This escrow holds the emission tokens that will be distributed to LPs. The market program enforces that sufficient tokens are escrowed before allowing emission configuration.