While reading the js library API, I saw this line:
If the index is provided, the generation of the address is not deterministic.
As previously mentioned, when generating an address you need to know the key index of the private key in order to get the same address each time. The libraries give you two options in order to get that key index: one is to supply it as an optional input parameter, the other is to get it deterministically.
However can anyone explain the meaning of deterministic? What can be nondeterministic if I use index to generate a new address?