6.3 Target Orders

有些时候，为了对组合进行管理，只设定组合中相应资产的数量、市值或者比例，而不管当前的持仓情况，通过order_target_xxx方法进行操作。
Target：

• size -> amount of shares, contracts in the portfolio of a specific asset

• value -> value in monetary units of the asset in the portfolio

• percent -> percentage (from current portfolio) value of the asset in the current portfolio

拿order_target_size 来看：

• If the target is greater than the position a buy is issued, with the difference target - position_size

Examples:

• Pos: 0, target: 7 -> buy(size=7 - 0) -> buy(size=7)

• Pos: 3, target: 7 -> buy(size=7 - 3) -> buy(size=4)

• Pos: -3, target: 7 -> buy(size=7 - -3) -> buy(size=10)

• Pos: -3, target: -2 -> buy(size=-2 - -3) -> buy(size=1)

• If the target is smaller than the position a sell is issued with the difference position_size - target

Examples:

• Pos: 0, target: -7 -> sell(size=0 - -7) -> sell(size=7)

• Pos: 3, target: -7 -> sell(size=3 - -7) -> sell(size=10)

• Pos: -3, target: -7 -> sell(size=-3 - -7) -> sell(size=4)

• Pos: 3, target: 2 -> sell(size=3 - 2) -> sell(size=1)

When targetting a value with order_target_value, the current value of the asset in the portfolio and the position size are both taken into account to decide what the final underlying operation will be. The reasoning:

If position size is negative (short) and the target value has to be greater than the current value, this means: sell more

As such the logic works as follows:

• If target > value and size >=0 -> buy

• If target > value and size < 0 -> sell

• If target < value and size >= 0 -> sell

• If target < value and size < 0 -> buy

The logic for order_target_percent is the same as that of order_target_value. This method simply takes into account the current total value of the portfolio to determine the target value for the asset.