Contract 0x0f110c55efe62c16d553a3d3464b77e1853d0e97

 
 
Txn Hash
Method
Block
From
To
Value [Txn Fee]
0xa18446d2b015791ed82bea684dd7fe1a174fe3e9bd6990eeea9514a6f75d8bc5Exchange385648012023-01-26 22:31:505 hrs 46 mins ago0x27646074b103015cbb2c807b3d42aee0196f1d49 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00577039604 46.12
0x94f9c9e118048cc99df59f88cff497113d9be313fc927e6e6105ae74e0375261Exchange385641722023-01-26 22:08:146 hrs 10 mins ago0x27646074b103015cbb2c807b3d42aee0196f1d49 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00577039604 46.12
0x6791e1a3368259813a5eb23179b0c5e2a0acaee02373ad85656c05e68857da4cExchange385633772023-01-26 21:38:526 hrs 39 mins ago0x27646074b103015cbb2c807b3d42aee0196f1d49 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00577039604 46.12
0x85f0d4d67219be8b48654a248d022c38df45ece668a1d1445e2d4506d9825a7bExchange384403222023-01-23 19:16:263 days 9 hrs ago0x27646074b103015cbb2c807b3d42aee0196f1d49 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.005796920844 46.332
0xfb6b2ef30148d66b76557fcac73a54bab19b3b87d246bf1767fa3c02a32e4e5eRemove_liquidity...384396912023-01-23 18:53:323 days 9 hrs ago0x68b7fb0be99a826e3a08ca23b1e0114e4d922b3a IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00454457954 46.89194292
0x47df8f24ca2829c69bbf4c35108f0fa2c42ea7ae1c7a8f0623582f4dbf3f9bb7Remove_liquidity...384008472023-01-22 19:42:254 days 8 hrs ago0x1c2fab0ac9be26b67a4494ad1f9fafa6306c9214 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.005031365789 45.063733
0x7c91a1c6bfcae6c0fd88064ddd97104a2eaf9df99cd6959982114ef6e04740d2Remove_liquidity...383900302023-01-22 13:08:194 days 15 hrs ago0xdb83a9af6c17ddaa5142a863592b340ebd9ba749 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.005350202941 56.09296339
0xa7e90923a7b5d82ef25c7402464c6507de95f08d1dae3d1c7bf13e38d30f2683Remove_liquidity383618142023-01-21 20:18:475 days 7 hrs ago0x27ceeb99790362b64c21205cee10e75b43b79afb IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.005388198879 52.604232
0x530c2ab6c20618b69056cd02ee524a4136910d9f70c839bcd53a14d71b689290Remove_liquidity...383532602023-01-21 14:54:405 days 13 hrs ago0xf41ab39c1aac27ddddbded1117b2f840d49b80a3 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.006867636175 70.890264718
0x319633760bd9c71317ca7a3ac0318d01a647f919c9d13234111ba153be80878fRemove_liquidity...383513642023-01-21 13:47:325 days 14 hrs ago0x4ca061759af7d1b93f1d2f6ec48f37b47ba844f0 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.004942256139 51.815939644
0xe527f692ba3942dafd9ded72099e98debcf8b1ef8182834cef0eca1b784944f4Remove_liquidity...383037162023-01-20 9:10:066 days 19 hrs ago0x56bd5f6b28c09bc0a8f970472937f3689f7a2179 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00572800423 59.114971
0xd07a1ac4adcd165df4bd4c5c29add92544eece7f6323a71323635060f063d82cRemove_liquidity382061602023-01-17 21:10:059 days 7 hrs ago0x0a9ea1adeed852cc2dc59038503878f5b13ec0f4 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.003345545754 38.003314149
0xfeec98d05cfd0a81b62e6056d63effbe5b3149592ee30a2d23bc780ae5c07163Exchange382016252023-01-17 18:25:259 days 9 hrs ago0x27646074b103015cbb2c807b3d42aee0196f1d49 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00652109804 52.12
0xda8fbcbb737b7db0a3948b69d952c7d43fad7467dc01fdbb1166d63b33de7599Remove_liquidity...381630082023-01-16 19:31:2910 days 8 hrs ago0x2aa7019c6799c956de45689aff6d1c1d761a8749 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.004503504655 40.344585095
0xf2f17814852ff83502bae777eee7c4b63cc16fd4fc572bd77ce5a57ae0e5f971Remove_liquidity...381518692023-01-16 13:03:2110 days 15 hrs ago0x3e184af75c982e16eeaf97c9a66cc607d8966f2d IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.005931193947 62.184229009
0xcc4d18e68d30ef2c9feb79f8da827d8cc8f29c2c528fb1ca0a2aaa22244a88abRemove_liquidity...381497932023-01-16 11:52:0110 days 16 hrs ago0x23615bd507f6f885836203f1d5cf70c743b52da2 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00543671757
0x75e20111abcf49e4c3c9dff4c0dd2f7791b2b1e604dfd103db992da21e816fd1Remove_liquidity...381496212023-01-16 11:46:0310 days 16 hrs ago0x23615bd507f6f885836203f1d5cf70c743b52da2 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.0083719575
0xa635cf4e8c69e52568549f6bb431958eaa22ae78c0620484e747ffbbf7a781afRemove_liquidity...381490572023-01-16 11:26:4310 days 16 hrs ago0x23615bd507f6f885836203f1d5cf70c743b52da2 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00814869873
0x46d26e6f53fd2c3291f2fc6c4dcec3ecba7f75756d00f1b90c9ed7c68f63de81Remove_liquidity...381489222023-01-16 11:21:5710 days 16 hrs ago0x23615bd507f6f885836203f1d5cf70c743b52da2 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00636131457
0x6b5dc3205699748348ba8ac0fa9ad0fe938e630a433b34abe6c731a6393af422Remove_liquidity...381488232023-01-16 11:18:3410 days 16 hrs ago0x23615bd507f6f885836203f1d5cf70c743b52da2 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00625105656
0x93acee41e60f27925b0bd1d1eabf096e3a07d852b19c32afe19784bbcdfdb2f0Remove_liquidity...381485052023-01-16 11:05:3010 days 17 hrs ago0x23615bd507f6f885836203f1d5cf70c743b52da2 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00600780663
0x1331b14cc8b4c20bb81408f1bbee694f6654e32f311593e3db02027ceaf5ca3eRemove_liquidity381253242023-01-15 21:43:4111 days 6 hrs ago0x6129aeaf582dd8b748772e19fb7a80af26d4c2d3 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.003490870122 39.654108377
0x49a6aa05537d581add3cb1b9a36f6debd10f67fdd94593ff965a48894fb51aeaExchange381216962023-01-15 19:38:4911 days 8 hrs ago0x27646074b103015cbb2c807b3d42aee0196f1d49 IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00552016204 44.12
0x0ea51325e13edead06ca881d68feecf3d327cbf0b91136d0ae1ba726c82b54f0Remove_liquidity...379942162023-01-12 18:05:0214 days 10 hrs ago0x01a6f583f32b97e51bd2ecfa7ad8200f4f779f5b IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.012368585126 129.675565637
0x3f5bf90dee7ea818c768efe21e4a9f9045032cb12fd96578c3908263e7963054Remove_liquidity...379506732023-01-11 16:55:4015 days 11 hrs ago0x77614f41b5489f1c11445c7661b7a3bb4f7631bb IN  0x0f110c55efe62c16d553a3d3464b77e1853d0e970 MATIC0.00417144933 43.734594212
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0x4e3cb6fcb467c567a515a041a5f5ba22689fd51652d5b468444e6e986d8840e9307102972022-07-14 10:20:20196 days 17 hrs ago 0x722272d36ef0da72ff51c5a65db7b870e2e8d4ee  Contract Creation0 MATIC
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Minimal Proxy Contract for 0x571ff5b7b346f706aa48d696a9a4a288e9bb4091

Contract Name:
Vyper_contract

Compiler Version
vyper:0.2.15

Optimization Enabled:
N/A

Other Settings:
, None license
Decompile ByteCode

Contract Source Code (Vyper language format)

# @version 0.2.15
"""
@title StableSwap
@author Curve.Fi
@license Copyright (c) Curve.Fi, 2020-2021 - all rights reserved
@notice 2 coin pool implementation with no lending
@dev ERC20 support for return True/revert, return True/False, return None
"""

from vyper.interfaces import ERC20

interface Factory:
    def convert_fees() -> bool: nonpayable
    def get_fee_receiver(_pool: address) -> address: view
    def admin() -> address: view


event Transfer:
    sender: indexed(address)
    receiver: indexed(address)
    value: uint256

event Approval:
    owner: indexed(address)
    spender: indexed(address)
    value: uint256

event TokenExchange:
    buyer: indexed(address)
    sold_id: int128
    tokens_sold: uint256
    bought_id: int128
    tokens_bought: uint256

event AddLiquidity:
    provider: indexed(address)
    token_amounts: uint256[N_COINS]
    fees: uint256[N_COINS]
    invariant: uint256
    token_supply: uint256

event RemoveLiquidity:
    provider: indexed(address)
    token_amounts: uint256[N_COINS]
    fees: uint256[N_COINS]
    token_supply: uint256

event RemoveLiquidityOne:
    provider: indexed(address)
    token_amount: uint256
    coin_amount: uint256
    token_supply: uint256

event RemoveLiquidityImbalance:
    provider: indexed(address)
    token_amounts: uint256[N_COINS]
    fees: uint256[N_COINS]
    invariant: uint256
    token_supply: uint256

event RampA:
    old_A: uint256
    new_A: uint256
    initial_time: uint256
    future_time: uint256

event StopRampA:
    A: uint256
    t: uint256


N_COINS: constant(int128) = 2
PRECISION: constant(uint256) = 10 ** 18

FEE_DENOMINATOR: constant(uint256) = 10 ** 10
ADMIN_FEE: constant(uint256) = 5000000000

A_PRECISION: constant(uint256) = 100
MAX_A: constant(uint256) = 10 ** 6
MAX_A_CHANGE: constant(uint256) = 10
MIN_RAMP_TIME: constant(uint256) = 86400

factory: address

coins: public(address[N_COINS])
balances: public(uint256[N_COINS])
fee: public(uint256)  # fee * 1e10

initial_A: public(uint256)
future_A: public(uint256)
initial_A_time: public(uint256)
future_A_time: public(uint256)

rate_multipliers: uint256[N_COINS]

name: public(String[64])
symbol: public(String[32])

balanceOf: public(HashMap[address, uint256])
allowance: public(HashMap[address, HashMap[address, uint256]])
totalSupply: public(uint256)


@external
def __init__():
    # we do this to prevent the implementation contract from being used as a pool
    self.fee = 31337


@external
def initialize(
    _name: String[32],
    _symbol: String[10],
    _coins: address[4],
    _rate_multipliers: uint256[4],
    _A: uint256,
    _fee: uint256,
):
    """
    @notice Contract constructor
    @param _name Name of the new pool
    @param _symbol Token symbol
    @param _coins List of all ERC20 conract addresses of coins
    @param _rate_multipliers List of number of decimals in coins
    @param _A Amplification coefficient multiplied by n ** (n - 1)
    @param _fee Fee to charge for exchanges
    """
    # check if fee was already set to prevent initializing contract twice
    assert self.fee == 0

    for i in range(N_COINS):
        coin: address = _coins[i]
        if coin == ZERO_ADDRESS:
            break
        self.coins[i] = coin
        self.rate_multipliers[i] = _rate_multipliers[i]

    A: uint256 = _A * A_PRECISION
    self.initial_A = A
    self.future_A = A
    self.fee = _fee
    self.factory = msg.sender

    self.name = concat("Curve.fi Factory Plain Pool: ", _name)
    self.symbol = concat(_symbol, "-f")

    # fire a transfer event so block explorers identify the contract as an ERC20
    log Transfer(ZERO_ADDRESS, self, 0)


### ERC20 Functionality ###

@view
@external
def decimals() -> uint256:
    """
    @notice Get the number of decimals for this token
    @dev Implemented as a view method to reduce gas costs
    @return uint256 decimal places
    """
    return 18


@internal
def _transfer(_from: address, _to: address, _value: uint256):
    # # NOTE: vyper does not allow underflows
    # #       so the following subtraction would revert on insufficient balance
    self.balanceOf[_from] -= _value
    self.balanceOf[_to] += _value

    log Transfer(_from, _to, _value)


@external
def transfer(_to : address, _value : uint256) -> bool:
    """
    @dev Transfer token for a specified address
    @param _to The address to transfer to.
    @param _value The amount to be transferred.
    """
    self._transfer(msg.sender, _to, _value)
    return True


@external
def transferFrom(_from : address, _to : address, _value : uint256) -> bool:
    """
     @dev Transfer tokens from one address to another.
     @param _from address The address which you want to send tokens from
     @param _to address The address which you want to transfer to
     @param _value uint256 the amount of tokens to be transferred
    """
    self._transfer(_from, _to, _value)

    _allowance: uint256 = self.allowance[_from][msg.sender]
    if _allowance != MAX_UINT256:
        self.allowance[_from][msg.sender] = _allowance - _value

    return True


@external
def approve(_spender : address, _value : uint256) -> bool:
    """
    @notice Approve the passed address to transfer the specified amount of
            tokens on behalf of msg.sender
    @dev Beware that changing an allowance via this method brings the risk that
         someone may use both the old and new allowance by unfortunate transaction
         ordering: https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    @param _spender The address which will transfer the funds
    @param _value The amount of tokens that may be transferred
    @return bool success
    """
    self.allowance[msg.sender][_spender] = _value

    log Approval(msg.sender, _spender, _value)
    return True


### StableSwap Functionality ###

@view
@external
def get_balances() -> uint256[N_COINS]:
    return self.balances


@view
@internal
def _A() -> uint256:
    """
    Handle ramping A up or down
    """
    t1: uint256 = self.future_A_time
    A1: uint256 = self.future_A

    if block.timestamp < t1:
        A0: uint256 = self.initial_A
        t0: uint256 = self.initial_A_time
        # Expressions in uint256 cannot have negative numbers, thus "if"
        if A1 > A0:
            return A0 + (A1 - A0) * (block.timestamp - t0) / (t1 - t0)
        else:
            return A0 - (A0 - A1) * (block.timestamp - t0) / (t1 - t0)

    else:  # when t1 == 0 or block.timestamp >= t1
        return A1


@view
@external
def admin_fee() -> uint256:
    return ADMIN_FEE


@view
@external
def A() -> uint256:
    return self._A() / A_PRECISION


@view
@external
def A_precise() -> uint256:
    return self._A()


@pure
@internal
def _xp_mem(_rates: uint256[N_COINS], _balances: uint256[N_COINS]) -> uint256[N_COINS]:
    result: uint256[N_COINS] = empty(uint256[N_COINS])
    for i in range(N_COINS):
        result[i] = _rates[i] * _balances[i] / PRECISION
    return result


@pure
@internal
def get_D(_xp: uint256[N_COINS], _amp: uint256) -> uint256:
    """
    D invariant calculation in non-overflowing integer operations
    iteratively

    A * sum(x_i) * n**n + D = A * D * n**n + D**(n+1) / (n**n * prod(x_i))

    Converging solution:
    D[j+1] = (A * n**n * sum(x_i) - D[j]**(n+1) / (n**n prod(x_i))) / (A * n**n - 1)
    """
    S: uint256 = 0
    for x in _xp:
        S += x
    if S == 0:
        return 0

    D: uint256 = S
    Ann: uint256 = _amp * N_COINS
    for i in range(255):
        D_P: uint256 = D * D / _xp[0] * D / _xp[1] / (N_COINS)**2
        Dprev: uint256 = D
        D = (Ann * S / A_PRECISION + D_P * N_COINS) * D / ((Ann - A_PRECISION) * D / A_PRECISION + (N_COINS + 1) * D_P)
        # Equality with the precision of 1
        if D > Dprev:
            if D - Dprev <= 1:
                return D
        else:
            if Dprev - D <= 1:
                return D
    # convergence typically occurs in 4 rounds or less, this should be unreachable!
    # if it does happen the pool is borked and LPs can withdraw via `remove_liquidity`
    raise


@view
@internal
def get_D_mem(_rates: uint256[N_COINS], _balances: uint256[N_COINS], _amp: uint256) -> uint256:
    xp: uint256[N_COINS] = self._xp_mem(_rates, _balances)
    return self.get_D(xp, _amp)


@view
@external
def get_virtual_price() -> uint256:
    """
    @notice The current virtual price of the pool LP token
    @dev Useful for calculating profits
    @return LP token virtual price normalized to 1e18
    """
    amp: uint256 = self._A()
    xp: uint256[N_COINS] = self._xp_mem(self.rate_multipliers, self.balances)
    D: uint256 = self.get_D(xp, amp)
    # D is in the units similar to DAI (e.g. converted to precision 1e18)
    # When balanced, D = n * x_u - total virtual value of the portfolio
    return D * PRECISION / self.totalSupply


@view
@external
def calc_token_amount(_amounts: uint256[N_COINS], _is_deposit: bool) -> uint256:
    """
    @notice Calculate addition or reduction in token supply from a deposit or withdrawal
    @dev This calculation accounts for slippage, but not fees.
         Needed to prevent front-running, not for precise calculations!
    @param _amounts Amount of each coin being deposited
    @param _is_deposit set True for deposits, False for withdrawals
    @return Expected amount of LP tokens received
    """
    amp: uint256 = self._A()
    balances: uint256[N_COINS] = self.balances

    D0: uint256 = self.get_D_mem(self.rate_multipliers, balances, amp)
    for i in range(N_COINS):
        amount: uint256 = _amounts[i]
        if _is_deposit:
            balances[i] += amount
        else:
            balances[i] -= amount
    D1: uint256 = self.get_D_mem(self.rate_multipliers, balances, amp)
    diff: uint256 = 0
    if _is_deposit:
        diff = D1 - D0
    else:
        diff = D0 - D1
    return diff * self.totalSupply / D0


@external
@nonreentrant('lock')
def add_liquidity(
    _amounts: uint256[N_COINS],
    _min_mint_amount: uint256,
    _receiver: address = msg.sender
) -> uint256:
    """
    @notice Deposit coins into the pool
    @param _amounts List of amounts of coins to deposit
    @param _min_mint_amount Minimum amount of LP tokens to mint from the deposit
    @param _receiver Address that owns the minted LP tokens
    @return Amount of LP tokens received by depositing
    """
    amp: uint256 = self._A()
    old_balances: uint256[N_COINS] = self.balances
    rates: uint256[N_COINS] = self.rate_multipliers

    # Initial invariant
    D0: uint256 = self.get_D_mem(rates, old_balances, amp)

    total_supply: uint256 = self.totalSupply
    new_balances: uint256[N_COINS] = old_balances
    for i in range(N_COINS):
        amount: uint256 = _amounts[i]
        if amount > 0:
            response: Bytes[32] = raw_call(
                self.coins[i],
                concat(
                    method_id("transferFrom(address,address,uint256)"),
                    convert(msg.sender, bytes32),
                    convert(self, bytes32),
                    convert(amount, bytes32),
                ),
                max_outsize=32,
            )
            if len(response) > 0:
                assert convert(response, bool)  # dev: failed transfer
            new_balances[i] += amount
            # end "safeTransferFrom"
        else:
            assert total_supply != 0  # dev: initial deposit requires all coins

    # Invariant after change
    D1: uint256 = self.get_D_mem(rates, new_balances, amp)
    assert D1 > D0

    # We need to recalculate the invariant accounting for fees
    # to calculate fair user's share
    fees: uint256[N_COINS] = empty(uint256[N_COINS])
    mint_amount: uint256 = 0
    if total_supply > 0:
        # Only account for fees if we are not the first to deposit
        base_fee: uint256 = self.fee * N_COINS / (4 * (N_COINS - 1))
        for i in range(N_COINS):
            ideal_balance: uint256 = D1 * old_balances[i] / D0
            difference: uint256 = 0
            new_balance: uint256 = new_balances[i]
            if ideal_balance > new_balance:
                difference = ideal_balance - new_balance
            else:
                difference = new_balance - ideal_balance
            fees[i] = base_fee * difference / FEE_DENOMINATOR
            self.balances[i] = new_balance - (fees[i] * ADMIN_FEE / FEE_DENOMINATOR)
            new_balances[i] -= fees[i]
        D2: uint256 = self.get_D_mem(rates, new_balances, amp)
        mint_amount = total_supply * (D2 - D0) / D0
    else:
        self.balances = new_balances
        mint_amount = D1  # Take the dust if there was any

    assert mint_amount >= _min_mint_amount, "Slippage screwed you"

    # Mint pool tokens
    total_supply += mint_amount
    self.balanceOf[_receiver] += mint_amount
    self.totalSupply = total_supply
    log Transfer(ZERO_ADDRESS, _receiver, mint_amount)

    log AddLiquidity(msg.sender, _amounts, fees, D1, total_supply)

    return mint_amount


@view
@internal
def get_y(i: int128, j: int128, x: uint256, xp: uint256[N_COINS]) -> uint256:
    """
    Calculate x[j] if one makes x[i] = x

    Done by solving quadratic equation iteratively.
    x_1**2 + x_1 * (sum' - (A*n**n - 1) * D / (A * n**n)) = D ** (n + 1) / (n ** (2 * n) * prod' * A)
    x_1**2 + b*x_1 = c

    x_1 = (x_1**2 + c) / (2*x_1 + b)
    """
    # x in the input is converted to the same price/precision

    assert i != j       # dev: same coin
    assert j >= 0       # dev: j below zero
    assert j < N_COINS  # dev: j above N_COINS

    # should be unreachable, but good for safety
    assert i >= 0
    assert i < N_COINS

    amp: uint256 = self._A()
    D: uint256 = self.get_D(xp, amp)
    S_: uint256 = 0
    _x: uint256 = 0
    y_prev: uint256 = 0
    c: uint256 = D
    Ann: uint256 = amp * N_COINS

    for _i in range(N_COINS):
        if _i == i:
            _x = x
        elif _i != j:
            _x = xp[_i]
        else:
            continue
        S_ += _x
        c = c * D / (_x * N_COINS)

    c = c * D * A_PRECISION / (Ann * N_COINS)
    b: uint256 = S_ + D * A_PRECISION / Ann  # - D
    y: uint256 = D

    for _i in range(255):
        y_prev = y
        y = (y*y + c) / (2 * y + b - D)
        # Equality with the precision of 1
        if y > y_prev:
            if y - y_prev <= 1:
                return y
        else:
            if y_prev - y <= 1:
                return y
    raise


@view
@external
def get_dy(i: int128, j: int128, dx: uint256) -> uint256:
    """
    @notice Calculate the current output dy given input dx
    @dev Index values can be found via the `coins` public getter method
    @param i Index value for the coin to send
    @param j Index valie of the coin to recieve
    @param dx Amount of `i` being exchanged
    @return Amount of `j` predicted
    """
    rates: uint256[N_COINS] = self.rate_multipliers
    xp: uint256[N_COINS] = self._xp_mem(rates, self.balances)

    x: uint256 = xp[i] + (dx * rates[i] / PRECISION)
    y: uint256 = self.get_y(i, j, x, xp)
    dy: uint256 = xp[j] - y - 1
    fee: uint256 = self.fee * dy / FEE_DENOMINATOR
    return (dy - fee) * PRECISION / rates[j]


@external
@nonreentrant('lock')
def exchange(
    i: int128,
    j: int128,
    _dx: uint256,
    _min_dy: uint256,
    _receiver: address = msg.sender,
) -> uint256:
    """
    @notice Perform an exchange between two coins
    @dev Index values can be found via the `coins` public getter method
    @param i Index value for the coin to send
    @param j Index valie of the coin to recieve
    @param _dx Amount of `i` being exchanged
    @param _min_dy Minimum amount of `j` to receive
    @return Actual amount of `j` received
    """
    rates: uint256[N_COINS] = self.rate_multipliers
    old_balances: uint256[N_COINS] = self.balances
    xp: uint256[N_COINS] = self._xp_mem(rates, old_balances)

    x: uint256 = xp[i] + _dx * rates[i] / PRECISION
    y: uint256 = self.get_y(i, j, x, xp)

    dy: uint256 = xp[j] - y - 1  # -1 just in case there were some rounding errors
    dy_fee: uint256 = dy * self.fee / FEE_DENOMINATOR

    # Convert all to real units
    dy = (dy - dy_fee) * PRECISION / rates[j]
    assert dy >= _min_dy, "Exchange resulted in fewer coins than expected"

    dy_admin_fee: uint256 = dy_fee * ADMIN_FEE / FEE_DENOMINATOR
    dy_admin_fee = dy_admin_fee * PRECISION / rates[j]

    # Change balances exactly in same way as we change actual ERC20 coin amounts
    self.balances[i] = old_balances[i] + _dx
    # When rounding errors happen, we undercharge admin fee in favor of LP
    self.balances[j] = old_balances[j] - dy - dy_admin_fee

    response: Bytes[32] = raw_call(
        self.coins[i],
        concat(
            method_id("transferFrom(address,address,uint256)"),
            convert(msg.sender, bytes32),
            convert(self, bytes32),
            convert(_dx, bytes32),
        ),
        max_outsize=32,
    )
    if len(response) > 0:
        assert convert(response, bool)

    response = raw_call(
        self.coins[j],
        concat(
            method_id("transfer(address,uint256)"),
            convert(_receiver, bytes32),
            convert(dy, bytes32),
        ),
        max_outsize=32,
    )
    if len(response) > 0:
        assert convert(response, bool)

    log TokenExchange(msg.sender, i, _dx, j, dy)

    return dy


@external
@nonreentrant('lock')
def remove_liquidity(
    _burn_amount: uint256,
    _min_amounts: uint256[N_COINS],
    _receiver: address = msg.sender
) -> uint256[N_COINS]:
    """
    @notice Withdraw coins from the pool
    @dev Withdrawal amounts are based on current deposit ratios
    @param _burn_amount Quantity of LP tokens to burn in the withdrawal
    @param _min_amounts Minimum amounts of underlying coins to receive
    @param _receiver Address that receives the withdrawn coins
    @return List of amounts of coins that were withdrawn
    """
    total_supply: uint256 = self.totalSupply
    amounts: uint256[N_COINS] = empty(uint256[N_COINS])

    for i in range(N_COINS):
        old_balance: uint256 = self.balances[i]
        value: uint256 = old_balance * _burn_amount / total_supply
        assert value >= _min_amounts[i], "Withdrawal resulted in fewer coins than expected"
        self.balances[i] = old_balance - value
        amounts[i] = value

        response: Bytes[32] = raw_call(
            self.coins[i],
            concat(
                method_id("transfer(address,uint256)"),
                convert(_receiver, bytes32),
                convert(value, bytes32),
            ),
            max_outsize=32,
        )
        if len(response) > 0:
            assert convert(response, bool)

    total_supply -= _burn_amount
    self.balanceOf[msg.sender] -= _burn_amount
    self.totalSupply = total_supply
    log Transfer(msg.sender, ZERO_ADDRESS, _burn_amount)

    log RemoveLiquidity(msg.sender, amounts, empty(uint256[N_COINS]), total_supply)

    return amounts


@external
@nonreentrant('lock')
def remove_liquidity_imbalance(
    _amounts: uint256[N_COINS],
    _max_burn_amount: uint256,
    _receiver: address = msg.sender
) -> uint256:
    """
    @notice Withdraw coins from the pool in an imbalanced amount
    @param _amounts List of amounts of underlying coins to withdraw
    @param _max_burn_amount Maximum amount of LP token to burn in the withdrawal
    @param _receiver Address that receives the withdrawn coins
    @return Actual amount of the LP token burned in the withdrawal
    """
    amp: uint256 = self._A()
    rates: uint256[N_COINS] = self.rate_multipliers
    old_balances: uint256[N_COINS] = self.balances
    D0: uint256 = self.get_D_mem(rates, old_balances, amp)

    new_balances: uint256[N_COINS] = old_balances
    for i in range(N_COINS):
        amount: uint256 = _amounts[i]
        if amount != 0:
            new_balances[i] -= amount
            response: Bytes[32] = raw_call(
                self.coins[i],
                concat(
                    method_id("transfer(address,uint256)"),
                    convert(_receiver, bytes32),
                    convert(amount, bytes32),
                ),
                max_outsize=32,
            )
            if len(response) > 0:
                assert convert(response, bool)
    D1: uint256 = self.get_D_mem(rates, new_balances, amp)

    fees: uint256[N_COINS] = empty(uint256[N_COINS])
    base_fee: uint256 = self.fee * N_COINS / (4 * (N_COINS - 1))
    for i in range(N_COINS):
        ideal_balance: uint256 = D1 * old_balances[i] / D0
        difference: uint256 = 0
        new_balance: uint256 = new_balances[i]
        if ideal_balance > new_balance:
            difference = ideal_balance - new_balance
        else:
            difference = new_balance - ideal_balance
        fees[i] = base_fee * difference / FEE_DENOMINATOR
        self.balances[i] = new_balance - (fees[i] * ADMIN_FEE / FEE_DENOMINATOR)
        new_balances[i] -= fees[i]
    D2: uint256 = self.get_D_mem(rates, new_balances, amp)

    total_supply: uint256 = self.totalSupply
    burn_amount: uint256 = ((D0 - D2) * total_supply / D0) + 1
    assert burn_amount > 1  # dev: zero tokens burned
    assert burn_amount <= _max_burn_amount, "Slippage screwed you"

    total_supply -= burn_amount
    self.totalSupply = total_supply
    self.balanceOf[msg.sender] -= burn_amount
    log Transfer(msg.sender, ZERO_ADDRESS, burn_amount)
    log RemoveLiquidityImbalance(msg.sender, _amounts, fees, D1, total_supply)

    return burn_amount


@pure
@internal
def get_y_D(A: uint256, i: int128, xp: uint256[N_COINS], D: uint256) -> uint256:
    """
    Calculate x[i] if one reduces D from being calculated for xp to D

    Done by solving quadratic equation iteratively.
    x_1**2 + x_1 * (sum' - (A*n**n - 1) * D / (A * n**n)) = D ** (n + 1) / (n ** (2 * n) * prod' * A)
    x_1**2 + b*x_1 = c

    x_1 = (x_1**2 + c) / (2*x_1 + b)
    """
    # x in the input is converted to the same price/precision

    assert i >= 0  # dev: i below zero
    assert i < N_COINS  # dev: i above N_COINS

    S_: uint256 = 0
    _x: uint256 = 0
    y_prev: uint256 = 0
    c: uint256 = D
    Ann: uint256 = A * N_COINS

    for _i in range(N_COINS):
        if _i != i:
            _x = xp[_i]
        else:
            continue
        S_ += _x
        c = c * D / (_x * N_COINS)

    c = c * D * A_PRECISION / (Ann * N_COINS)
    b: uint256 = S_ + D * A_PRECISION / Ann
    y: uint256 = D

    for _i in range(255):
        y_prev = y
        y = (y*y + c) / (2 * y + b - D)
        # Equality with the precision of 1
        if y > y_prev:
            if y - y_prev <= 1:
                return y
        else:
            if y_prev - y <= 1:
                return y
    raise


@view
@internal
def _calc_withdraw_one_coin(_burn_amount: uint256, i: int128) -> uint256[2]:
    # First, need to calculate
    # * Get current D
    # * Solve Eqn against y_i for D - _token_amount
    amp: uint256 = self._A()
    rates: uint256[N_COINS] = self.rate_multipliers
    xp: uint256[N_COINS] = self._xp_mem(rates, self.balances)
    D0: uint256 = self.get_D(xp, amp)

    total_supply: uint256 = self.totalSupply
    D1: uint256 = D0 - _burn_amount * D0 / total_supply
    new_y: uint256 = self.get_y_D(amp, i, xp, D1)

    base_fee: uint256 = self.fee * N_COINS / (4 * (N_COINS - 1))
    xp_reduced: uint256[N_COINS] = empty(uint256[N_COINS])

    for j in range(N_COINS):
        dx_expected: uint256 = 0
        xp_j: uint256 = xp[j]
        if j == i:
            dx_expected = xp_j * D1 / D0 - new_y
        else:
            dx_expected = xp_j - xp_j * D1 / D0
        xp_reduced[j] = xp_j - base_fee * dx_expected / FEE_DENOMINATOR

    dy: uint256 = xp_reduced[i] - self.get_y_D(amp, i, xp_reduced, D1)
    dy_0: uint256 = (xp[i] - new_y) * PRECISION / rates[i]  # w/o fees
    dy = (dy - 1) * PRECISION / rates[i]  # Withdraw less to account for rounding errors

    return [dy, dy_0 - dy]


@view
@external
def calc_withdraw_one_coin(_burn_amount: uint256, i: int128) -> uint256:
    """
    @notice Calculate the amount received when withdrawing a single coin
    @param _burn_amount Amount of LP tokens to burn in the withdrawal
    @param i Index value of the coin to withdraw
    @return Amount of coin received
    """
    return self._calc_withdraw_one_coin(_burn_amount, i)[0]


@external
@nonreentrant('lock')
def remove_liquidity_one_coin(
    _burn_amount: uint256,
    i: int128,
    _min_received: uint256,
    _receiver: address = msg.sender,
) -> uint256:
    """
    @notice Withdraw a single coin from the pool
    @param _burn_amount Amount of LP tokens to burn in the withdrawal
    @param i Index value of the coin to withdraw
    @param _min_received Minimum amount of coin to receive
    @param _receiver Address that receives the withdrawn coins
    @return Amount of coin received
    """
    dy: uint256[2] = self._calc_withdraw_one_coin(_burn_amount, i)
    assert dy[0] >= _min_received, "Not enough coins removed"

    self.balances[i] -= (dy[0] + dy[1] * ADMIN_FEE / FEE_DENOMINATOR)
    total_supply: uint256 = self.totalSupply - _burn_amount
    self.totalSupply = total_supply
    self.balanceOf[msg.sender] -= _burn_amount
    log Transfer(msg.sender, ZERO_ADDRESS, _burn_amount)

    response: Bytes[32] = raw_call(
        self.coins[i],
        concat(
            method_id("transfer(address,uint256)"),
            convert(_receiver, bytes32),
            convert(dy[0], bytes32),
        ),
        max_outsize=32,
    )
    if len(response) > 0:
        assert convert(response, bool)

    log RemoveLiquidityOne(msg.sender, _burn_amount, dy[0], total_supply)

    return dy[0]


@external
def ramp_A(_future_A: uint256, _future_time: uint256):
    assert msg.sender == Factory(self.factory).admin()  # dev: only owner
    assert block.timestamp >= self.initial_A_time + MIN_RAMP_TIME
    assert _future_time >= block.timestamp + MIN_RAMP_TIME  # dev: insufficient time

    _initial_A: uint256 = self._A()
    _future_A_p: uint256 = _future_A * A_PRECISION

    assert _future_A > 0 and _future_A < MAX_A
    if _future_A_p < _initial_A:
        assert _future_A_p * MAX_A_CHANGE >= _initial_A
    else:
        assert _future_A_p <= _initial_A * MAX_A_CHANGE

    self.initial_A = _initial_A
    self.future_A = _future_A_p
    self.initial_A_time = block.timestamp
    self.future_A_time = _future_time

    log RampA(_initial_A, _future_A_p, block.timestamp, _future_time)


@external
def stop_ramp_A():
    assert msg.sender == Factory(self.factory).admin()  # dev: only owner

    current_A: uint256 = self._A()
    self.initial_A = current_A
    self.future_A = current_A
    self.initial_A_time = block.timestamp
    self.future_A_time = block.timestamp
    # now (block.timestamp < t1) is always False, so we return saved A

    log StopRampA(current_A, block.timestamp)


@view
@external
def admin_balances(i: uint256) -> uint256:
    return ERC20(self.coins[i]).balanceOf(self) - self.balances[i]


@external
def withdraw_admin_fees():
    receiver: address = Factory(self.factory).get_fee_receiver(self)

    for i in range(N_COINS):
        coin: address = self.coins[i]
        fees: uint256 = ERC20(coin).balanceOf(self) - self.balances[i]
        raw_call(
            coin,
            concat(
                method_id("transfer(address,uint256)"),
                convert(receiver, bytes32),
                convert(fees, bytes32)
            )
        )

Contract ABI

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