The Rebalancing AMM (RAMM) is an AMM that takes prices from an oracle in order to avoid impermanent loss. This code was written for the Solana network using Seahorse 0.2.5.

The particular code of this repository is designed for a SOL/USDC/USDT pool, but with a few tweaks in can be easily adapted to any pool with any number of tokens.

One of the features of the OAMM is that liquidity providers can provide liquidity of just one asset, and the pool will mint a certain type of LP tokens according to the asset the liquidity provider is depositing. In consequence, this particular pool will mint three types of LP tokens: LPSOL, LPUSDC and LPUSDT.

Each OAMM pool consists of a single account that belongs to the oamm class and contains the data described below.

• balance_sol: f64 The current balance of SOL in the pool.

• balance_usdc: f64 The current balance of USDC in the pool.

• balance_usdt: f64 The current balance of USDT in the pool.

• lp_sol_tokens: f64 The current amount of LPSOL tokens in circulation.

• lp_usdc_tokens: f64 The current amount of LPUSDT tokens in circulation.

• lp_usdt_tokens: f64 The current amount of LPUSDC tokens in circulation.

• base_fee: f64 The base fee that the pool charges. The suggested value for the Solana network is 0.0008, which amounts to 0.08%.

• protocol_fee: f64 The share of the fees that the protocol charges for itself. The suggested value is 0.5, which means that half of the collected fees will be kept as revenue for the protocol, while the other half will be deposited into the pool and shared among the liquidity providers.

• base_leverage: f64 The base leverage parameter that the pool will use. This serves to concentrate liquidity around the current market price. The suggested value for this parameter is 100.

• delta: f64 The maximum deviation in the imbalances ratios permitted. The suggested value for this parameter is 0.25, which means that the imbalance ratios that are allowed are those between 0.75 and 1.25. Trades that push imbalance ratios outside this range will not be allowed. This parameter is designed to prevent the pool from being heavy unbalanced.

• bump: u8 The value of the bump parameter of the pool account.

Before describing what our program does, we will describe all the Solana accounts that are involved in the different instructions.

Pool accounts

• pool: The Solana account of the pool. Belongs to the oamm class as described above. Holds the SOL deposited into the pool.

• pool_usdc_tkn_acc: The TokenAccount that will hold the USDC deposited into the pool. The owner of this account is the pool's account.

• pool_usdc_tkn_acc: The TokenAccount that will hold the USDT deposited into the pool. The owner of this account is the pool's account.

• mint_lpsol: The TokenMint account that will mint and burn the LPSOL tokens.

• mint_lpusdc: The TokenMint account that will mint and burn the LPUSDC tokens.

• mint_lpusdt: The TokenMint account that will mint and burn the LPUSDT tokens.

User accounts

• user: Signer account. The account of the user that interacts with the OAMM.

• user_usdc_tkn_acc: User's TokenAccount that holds USDC. Its owner is the user account.

• user_usdt_tkn_acc: User's TokenAccount that holds USDT. Its owner is the user account.

• user_lp_sol_tkn_acc: User's TokenAccount that holds LPSOL. Its owner is the user account.

• user_lp_usdc_tkn_acc: User's TokenAccount that holds LPUSDC. Its owner is the user account.

• user_lp_usdt_tkn_acc: User's TokenAccount that holds LPUSDT. Its owner is the user account.

Price accounts

• price_account_sol: The Pyth network Solana account that tracks the price of the pair SOL/USD.

• price_account_usdc: The Pyth network Solana account that tracks the price of the pair USDC/USD.

• price_account_usdt: The Pyth network Solana account that tracks the price of the pair USDT/USD.

Fee accounts

• fee_acc_sol: Solana account that holds the fees collected in SOL.

• fee_acc_usdc: TokenAccount that holds the fees collected in USDC.

• fee_acc_usdt: TokenAccount that holds the fees collected in USDT.

Remark: When a parameter given to an instruction is denoted by *_usd_tkn_acc instead of *_usdc_tkn_acc or *_usdt_tkn_acc it means that the instruction will be used for both cases and the account that is passed in as a parameter should be the one that corresponds to the token that will be traded. A similar reasoning applies when we use fee_acc_usd instead of fee_acc_usdc or fee_acc_usdt.

Now, we describe our program's instructions.

• init: Initializes the pool account and the three TokenMint accounts that correspond to the three types of LP tokens to be minted. Takes as parameters basefee, protocolfee, baseleverage and delta, which are set and fixed with this instruction and can not be changed later.

• deposit_sol: Performs a liquidity deposit of a certain amount of SOL. Its parameters are amount_sol (the amount of SOL to be provided as liquidity), the corresponding Solana accounts, TokenAccounts and TokenMint accounts needed, and the price accounts.

• deposit_usdc: Performs a liquidity deposit of a certain amount of USDC. Its parameters are amount_usdc (the amount of USDC to be deposited), the corresponding Solana accounts, TokenAccounts and TokenMint accounts needed, and the price accounts.

• deposit_usdt: Performs a liquidity deposit of a certain amount of USDT. Its parameters are amount_usdt (the amount of USDT to be deposited), the corresponding Solana accounts, TokenAccounts and TokenMint accounts needed, and the price accounts.

• withdraw_sol: Performs a liquidity withdrawal of SOL. Its parameters are amount_lp_sol, which is the amount of LPSOL to be redeemed, the corresponding Solana accounts, TokenAccounts and TokenMint accounts needed, and the price accounts.

• withdraw_usdc: Performs a liquidity withdrawal of USDC. Its parameters are amount_lp_usdc, which is the amount of LPUSDC to be redeemed, the corresponding Solana accounts, TokenAccounts and TokenMint accounts needed, and the price accounts.

• withdraw_usdt: Performs a liquidity withdrawal of USDT. Its parameters are amount_lp_usdt, which is the amount of LPUSDT to be redeemed, the corresponding Solana accounts, TokenAccounts and TokenMint accounts needed, and the price accounts.

• trade_sol_in: Performs a trade in which SOL goes into the pool and either USDC or USDT goes out of the pool. Apart from the necessary accounts, the parameters of this instruction are amount_sol_in, amount_usd_out and token_out. The parameter token_out is a string that can be USDC or USDT according to which token the user wants to obtain. On the other hand, if the parameter amount_sol_in is not zero, the trade is performed as if the user deposited amount_sol_in SOL into the pool, and the program computes the amount of either USDC or USDT to be given to the user. In this case, the parameter amount_usd_out is ignored. If amount_sol_in is zero, the trade is performed as if the user wants to obtain amount_usd_out of either USDC or USDT from the pool, and the program computes the amount of SOL that the user needs to deposit.

• trade_sol_out: Performs a trade in which SOL goes out of the pool and either USDC or USDT goes into the pool. Apart from the necessary accounts, the parameters of this instruction are amount_usd_in, amount_sol_out and token_in. The parameter token_in is a string that can be USDC or USDT according to which token the user will deposit. On the other hand, if the parameter amount_usd_in is not zero, the trade is performed as if the user deposited amount_usd_in of either USDC or USDT into the pool, and the program computes the amount of SOL to be given to the user. In this case, the parameter amount_sol_out is ignored. If amount_usd_in is zero, the trade is performed as if the user wants to obtain amount_sol_out of SOL from the pool, and the program computes the amount of either USDC or USDT that the user needs to deposit.

• trade_usdc_in_usdt_out: Performs a trade in which USDC goes into the pool and USDT goes out of the pool. Apart from the necessary accounts, the parameters of this instruction are amount_usdc_in and amount_usdt_out. If amount_usdc_in is not zero, the trade is performed as if the user deposited amount_usdc_in USDC into the pool, and the program computes the amount of USDT to be given to the user. In this case, the parameter amount_usdt_out is ignored. If amount_usdc_in is zero, the trade is performed as if the user wants to obtain amount_usdt_out USDT from the pool, and the program computes the amount of USDC that the user needs to deposit.

• trade_usdt_in_usdc_out: Performs a trade in which USDT goes into the pool and USDC goes out of the pool. Apart from the necessary accounts, the parameters of this instruction are amount_usdt_in and amount_usdc_out. If amount_usdt_in is not zero, the trade is performed as if the user deposited amount_usdt_in USDT into the pool, and the program computes the amount of USDC to be given to the user. In this case, the parameter amount_usdc_out is ignored. If amount_usdt_in is zero, the trade is performed as if the user wants to obtain amount_usdc_out USDC from the pool, and the program computes the amount of USDT that the user needs to deposit.

• pool_state: Logs the current state of the pool: balances, LP tokens of each type issued and the current imbalance ratios.