Add ProjectQ

[mlazzarin]

Add ProjectQ to our benchmark suite.

[andrea-pasquale]

Thanks @mlazzarin for fixing the transpose state.
Are we supposed to do something else for this PR, maybe implement some missing gates, or we are good to go?

[mlazzarin]

We should double-check that our implementation is the optimal way of using ProjectQ, then enable gate fusion (once PR #17 is merged), finally we should run benchmarks and see if the results make sense somehow.

[mlazzarin]

We should double-check that our implementation is the optimal way of using ProjectQ, then enable gate fusion (once PR #17 is merged), finally we should run benchmarks and see if the results make sense somehow.

I added the LocalOptimizer compiler engine to the ProjectQ execution. Now I think that our implementation is optimal.
I can't find a way to use gate fusion, though. I will post some benchmarks ASAP, so that we can merge.

[mlazzarin]

I found a way to add gate fusion. I think that we are ready for review.

[stavros11]

Thanks for the implementation, looks good. Do you know if ProjectQ allows defining an arbitrary gate from matrix? If yes, we could give a try defining the U3 and unlock the qv circuit which works for all other libraries. If no, I guess there is no simple solution other than decomposing the U3 to other rotation which is probably not fair in terms of benchmarks.

Otherwise, if you agree, I will merge #17 to libraries and implement the options mechanism to switch the fusion flag here.

[mlazzarin]

Thanks for the implementation, looks good. Do you know if ProjectQ allows defining an arbitrary gate from matrix? If yes, we could give a try defining the U3 and unlock the qv circuit which works for all other libraries. If no, I guess there is no simple solution other than decomposing the U3 to other rotation which is probably not fair in terms of benchmarks.

Yes, I'll give it a try.

[andrea-pasquale]

Everything looks good to me.
I can also have a look at the U3 matrix.

[mlazzarin]

Now I merged the latest randomtests branch and I implemented some options for ProjectQ. Let me know if it's ok.