refactor: remove redundant function for getting bus demand

[danielolsen]

Purpose

Per discussion in #375, remove a redundant function. get_bus_demand is the fastest of the three identical functions:

>>> import timeit
>>> from postreise.analyze.transmission.congestion import map_demand_to_buses
>>> from powersimdata.input.input_data import get_bus_demand
>>> from powersimdata.scenario.helpers import calculate_bus_demand
>>> from powersimdata.scenario.scenario import Scenario
>>> scenario = Scenario(824)
>>> demand = scenario.state.get_demand()
>>> grid = scenario.state.get_grid()
>>> bus = grid.bus
>>> timeit.timeit(lambda: map_demand_to_buses(grid, demand), number=10)
75.39155149999999
>>> timeit.timeit(lambda: calculate_bus_demand(bus, demand), number=10)
45.56884489999993
>>> timeit.timeit(lambda: get_bus_demand(scenario.info, grid), number=10)
30.71693670000002

What the code is doing

• The docstring and parameter names of get_bus_demand are updated to reflect reality (I think the way we called InputData changed but we didn't update all the references to it).
• calculate_bus_demand is removed from helpers.py.
• Analyze and Create are refactored to use get_bus_demand instead of calculate_bus_demand.
• The construct_load_shed method of OutputData is updated to reflect the updated InputData init (can be tested before & after using scenario 398, which has old-style infeasibilities and triggers this code path).

Testing

All unit tests still pass.

Time estimate

10 minutes.

[rouille]

It looks good. Are you going to refactor PostREISE to import get_bus_demand

[danielolsen]

It looks good. Are you going to refactor PostREISE to import get_bus_demand

Yes, coming up soon.

[rouille]

Looks good

[BainanXia]

Looks good. Thanks.