Clifford simulation

[alexarice]

I believe classical simulation of clifford circuits should work quite nicely as an xdsl interpreter. It will unfortunately need some global state but I don't believe that this is a problem. I have some ideas for a sparse representation that should work well with allocating ancilla qubits mid-program.

TODO: check what stim does as apparently they do this well.

[superlopuh]

I have a thing for state it would be good to make it less weird, let's have a chat when you get to this.

[alexarice]

I'm hoping to come to Cambridge for retro/social so should book in some time then