Generalising class names about ciw HOT 8 OPEN

Hi @daffidwilde yes currently Ciw needs classes to be called 'Class 0', 'Class 1' etc. in order to force an ordering (unfortunatelt I think ciw's insides rely on this currently). I agree it would be much nicer to define own names, and would be more than happy for this to be changed.

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Internally, if the names are just being treated like indices then I imagine the dictionary could be iterated over in another way so ciw is completely class name invariant.

Yes I like this. Shouldn't be too many changes - and would still be back compatible 👍

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it could be possible to do this in such a way where you could pass lists without it actually needing special consideration.

That would be jolly nice to have both. I suspect that my suggestion would be implemented in a very similar way.

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Remind me @geraintpalmer, is there a purpose to class names?

What about not having names at all and instead of dictionaries you'd just have lists? (Essentially the names just become the indices of the list)

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I think lists of lists were the original idea, but became difficult to read. Compare the current (from the tutorial:

>>> import ciw
>>> N = ciw.create_network(
...     arrival_distributions={'Class 0': [ciw.dists.Exponential(1.0),
...                                        ciw.dists.NoArrivals(),
...                                        ciw.dists.NoArrivals()],
...                            'Class 1': [ciw.dists.Exponential(2.0),
...                                        ciw.dists.NoArrivals(),
...                                        ciw.dists.NoArrivals()]},
...     service_distributions={'Class 0': [ciw.dists.Exponential(4.0),
...                                        ciw.dists.Exponential(1.0),
...                                        ciw.dists.Deterministic(0.0)],
...                            'Class 1': [ciw.dists.Exponential(6.0),
...                                        ciw.dists.Deterministic(0.0),
...                                        ciw.dists.Exponential(1.0)]},
...     routing={'Class 0': [[0.0, 1.0, 0.0],
...                          [0.0, 0.0, 0.0],
...                          [0.0, 0.0, 0.0]],
...              'Class 1': [[0.0, 0.0, 1.0],
...                          [0.0, 0.0, 0.0],
...                          [0.0, 0.0, 0.0]]},
...     number_of_servers=[1, 2, 3],
... )

To the possibility of lists of lists (there may be a better way to present this, but I think it does reduce readability):

>>> import ciw
>>> N = ciw.create_network(
...     arrival_distributions=[[ciw.dists.Exponential(1.0),
...                             ciw.dists.NoArrivals(),
...                             ciw.dists.NoArrivals()],
...                            [ciw.dists.Exponential(2.0),
...                             ciw.dists.NoArrivals(),
...                             ciw.dists.NoArrivals()]],
...     service_distributions=[[ciw.dists.Exponential(4.0),
...                             ciw.dists.Exponential(1.0),
...                             ciw.dists.Deterministic(0.0)],
...                            [ciw.dists.Exponential(6.0),
...                             ciw.dists.Deterministic(0.0),
...                             ciw.dists.Exponential(1.0)]],
...     routing=[[[0.0, 1.0, 0.0],
...               [0.0, 0.0, 0.0],
...               [0.0, 0.0, 0.0]],
...              [[0.0, 0.0, 1.0],
...               [0.0, 0.0, 0.0],
...               [0.0, 0.0, 0.0]]],
...     number_of_servers=[1, 2, 3],
... )

It also makes setting priority classes more readable:

priority_classes={'Class 0': 0,
                  'Class 1': 1,
                  'Class 2': 1}

I think the idea of strings to represent customer classes. I like @daffidwilde's idea of allowing any string to represent a customer class, I think thta would make things much more reabable and meaningful to the user.

What do you both think @daffidwilde? @drvinceknight?

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What about not having names at all and instead of dictionaries you'd just have lists? (Essentially the names just become the indices of the list)

I prefer — from a usability perspective — to have a dictionary rather than nested lists.

Internally, if the names are just being treated like indices then I imagine the dictionary could be iterated over in another way so ciw is completely class name invariant.

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Sorry @geraintpalmer, it appears we replied at the same time. I concur with everything you’ve said.

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I'm not sure I see the improved readability using dictionaries but:

would still be back compatible

👍

(FYI, depending on how it's implemented given that internally lists are in fact just dictionaries it could be possible to do this in such a way where you could pass lists without it actually needing special consideration.)

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