在此框架中，传递的第二参数是要使用的拓扑。

In this framework, the second argument passed is the topology to use.

youdao

为集合里的每个键值执行指定的函数，传递每个键值作为第一参数和它相关的项作为第二参数。

Executes the specified function once for every key in the collection, passing each key, and its associated item as the first two parameters.

youdao

从集合中选择从（第二参数指定的）起始索引号（0）开始的最多（第一参数指定的）条目数（2）个条目。

Selects up to the first parameter (2) number of items from the collection starting (optionally) at the beginning index (0).

youdao

x1 The portfolio mean and variance will depend on x1 x1=1 in the way that if you put--if you made x1 = 1, it would be asset 1 x1=0 and if you made x1 = 0, then it would be the same as asset 2 returns.

投资组合的均值和方差取决于1,如果你令，投资组合的均值方差就与第一项资产相等1,如果你令，那么它们就会与第二项资产的参数相等。

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