Vehicle type model `REQUIRE_DATA_FOR_ALL_ALTS` needs to be True

[i-am-sijia]

Describe the bug

The vehicle type choice model creates alts_wide and alts_long tables, and they need to be in the same length and order, because this line of code assumes that for the final mapping of choices:

activitysim/activitysim/abm/models/vehicle_type_choice.py

Line 426 in a8e755f

choices["vehicle_type"] = choices["vehicle_type"].map(dict(enumerate(alts)))

However, the section of code below drops alternatives from alts_wide if there are alternatives that do not exist in the input VEHICLE_TYPE_DATA_FILE and if the optional REQUIRE_DATA_FOR_ALL_ALTS does not get defined or is set to False.

activitysim/activitysim/abm/models/vehicle_type_choice.py

Lines 217 to 224 in a8e755f

	if model_settings.get("REQUIRE_DATA_FOR_ALL_ALTS", False):
	# fail if alternative does not have an associated record in the data
	assert (
	len(missing_alts) == 0
	), f"missing vehicle data for alternatives:\n {missing_alts}"
	else:
	# eliminate alternatives if no vehicle type data
	alts_wide = alts_wide[alts_wide._merge != "left_only"]

This will make the alts_wide inconsistent with the alts_long, and make the final mapping of choices incorrect.

The model will still run, but the result will be incorrect.

To Reproduce

Steps to reproduce the behavior:

1. Delete the first row of the config/vehicle_type_data.csv
2. Run the existing prototype_mtc_extended model
3. The model will run, but it creates different result for vehicle type

Expected behavior

The model should fail if there are alternatives that do not exist in the vehicle type data. REQUIRE_DATA_FOR_ALL_ALTS should not be optional or and should be True. The IF condition on Line 217 can be replaced by the assert.

[dhensle]

Good find @i-am-sijia. I believe I have a fix (#790) in place to also filter alts_long if alts_wide gets filtered. I believe this means the REQUIRE_DATA_FOR_ALL_ALTS option is usable.

[i-am-sijia]

Ok, let's add REQUIRE_DATA_FOR_ALL_ALTS to the model documentation, and update the following blurb to remove "must be included in the file" -

activitysim/docs/models.rst

Lines 448 to 451 in a8e755f

	* ``VEHICLE_TYPE_DATA_FILE``: Filename for input vehicle type data. Must have columns ``body_type``, ``fuel_type``, and ``vehicle_year``.
	Vehicle ``age`` is computed using the ``FLEET_YEAR`` option. Data for every alternative specified in the ``combinatorial_alts`` option must be included
	in the file. Vehicle type data file will be joined to the alternatives and can be used in the utility expressions if ``PROBS_SPEC`` is not provided.
	If ``PROBS_SPEC`` is provided, the vehicle type data will be joined after a vehicle type is decided so the data can be used in downstream models.

More importantly, users should be warned when the software is dropping vehicle type alternatives. In case someone adds vehicle types (e.g., AVs) in the yaml but forgets to add vehicle types in the vehicle type data.

[dhensle]

Addressed with #790