Node parameters and node targets: best practice

[shumpohl]

I am writing a node that performs an accumulation measurement in a single electron transistor. I am wondering what the intended way is to handle different parameters for multiple identical components. Let's say I have a chip with two SETs on the left and on the right.

This is the simplified version of my node parameters

class AccumulationParameters(NodeParameters):
    targets_name: ClassVar[str] = "locations"
    locations: Optional[list[Literal["left", "right"]]] = None
    maximal_current: float = 1e-9
    accumulation_voltage_range: tuple[float, float] = (0.0, 1.0)

My node creates a qua program that accumulates all targeted SETs in parallel.

However, it is unclear to me how to handle different parameters for different targets. Let's say I want to allow a maximal current of 2e-9 for the right dot but keep the default parameter for the left. What would be the idiomatic way to set this up?

The only two solutions I see are to either tune the SETs sequentially or add separate parameters for all targets to the NodeParameters. The first gives up on parallelization and I am unsure how the second should be implemented in a scalable and readable way that can be processed by the surrounding qualibrate tooling.

[nulinspiratie]

Hey Simon, it's a good point, at the moment we don't have explicit support for per-target parameters. However, there are a few ways to tackle this:

Register parameters in QUAM

One possibility would be to add relevant target-specific parameters to the relevant QUAM components. So for example if you know that a certain SET has a specific maximal current, you could add it to the class definition: SET.maximal_current. That way, the node can directly access this.

Allow dictionaries for node parameters

One other option would be something like the following:

class AccumulationParameters(NodeParameters):
    targets_name: ClassVar[str] = "locations"
    locations: Optional[list[Literal["left", "right"]]] = None
    maximal_current: Dict[str, float] = field(default_factory=dict(default=2e-9))
    accumulation_voltage_range: tuple[float, float] = (0.0, 1.0)

You can then pass e.g. {"default: 2e9, "SET1": 1e-9}, and then in the code you could do something like

maximal_currents = node.parameters.maximal_current
for SET in SET_list:
    maximal_current = maximal_currents.get(SET.name, maximal_currents["default"])

Would either of these options satisfy your use case?

[shumpohl]

I think the second one works fine, especially for such a simple node. If I need something like that in a more complex node I will probably write a typed wrapper/config struct that is initialized with the NodeParameters.