More intuitive way to prescribe Flat topology on grids

[navidcy]

At the moment when we build a grid, the topology kwarg requires all 3 dimensions! For example, to build a 2D grid we do something like:

grid = RectilinearGrid(size=(16, 16),
                       x=(0, 2π),
                       y=(0, 2π),
                       topology = (Periodic, Periodic, Flat))

But requiring that third 3rd topology with Flat might seem a bit counterintuitive?

I'd think that by doing this:

grid = RectilinearGrid(size=(16, 16),
                       x=(0, 2π),
                       y=(0, 2π),
                       topology = (Periodic, Periodic))

then given that I prescribed x and y but not z the constructor should be able to figure out which are the non-Flat dimensions?

Would that be more intuitive you reckon?

[simone-silvestri]

I like the suggestion!

[glwagner]

I like this idea. The Flat dimension is inferred from the one that's omitted. I never thought of that!

[glwagner]

If we do the indexing thing that @simone-silvestri suggested then we could claim a user interface that does truly reduce from 3 to 1 dimension. I'm still worried about developers using that though, but maybe I shouldn't be worried (its my job to worry about hypotheticals)