QulacsBackend

[BrunoLiegiBastonLiegi]

This adds qulacs as an optional backend.

Checklist:

• Reviewers confirm new code works as expected.
• Tests are passing.
• Coverage does not decrease.
• Documentation is updated.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.85%. Comparing base (a61f9f7) to head (bb7417b).
Report is 188 commits behind head on master.

❗ Current head bb7417b differs from pull request most recent head 885c680

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1272      +/-   ##
==========================================
+ Coverage   99.82%   99.85%   +0.03%     
==========================================
  Files          72       74       +2     
  Lines       10560    10673     +113     
==========================================
+ Hits        10541    10658     +117     
+ Misses         19       15       -4     

Flag	Coverage Δ
unittests	99.85% <100.00%> (+0.03%)	⬆️

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[BrunoLiegiBastonLiegi]

@scarrazza some preliminary results for the qulacs backend, it looks indeed comparable with our `qibojit

1 core

8 cores

[scarrazza]

Thanks @BrunoLiegiBastonLiegi, could you please include some GPU curves too?

[BrunoLiegiBastonLiegi]

Yes I am trying to install the qulacs-gpu package on the cluster, but it requires a little bit of machinery. The pip install qulacs-gpu doesn't work, thus I am not sure how we could set that as an optional dependency.

[scarrazza]

Looks good, however we are missing documentation.

[BrunoLiegiBastonLiegi]

I added a small paragraph in the documentation about qulacs, there is not much to say as at this level we are supporting the basic features of qulacs only. What still needs to updated is the scheme in the getting started section that summarizes all the available backends. @MatteoRobbiati can I ask you hand with that?

[MatteoRobbiati]

I just opened a PR in the Xmind-diagrams repo adding Qulacs to diagrams.

[BrunoLiegiBastonLiegi]

Apparently there is some problem with qulacs and python3.12, even though it should be supporting python > 3.7 from what stated in the readme.

Edit: I was able to reproduce the problem locally, it looks like with python3.12 simply giving pip install qulacs doesn't work, as it fails to collect and install cmake and boost for some reason I presume. Manually installing them fixes the problem. qulacs/qulacs#645

[scarrazza]

@alecandido could you please try to install and run tests from this branch in your mac?

[BrunoLiegiBastonLiegi]

I tried on my mac (darwin) with python3.9 and it builds correctly

[scarrazza]

Did you run with poetry?

[BrunoLiegiBastonLiegi]

Yep poetry install --with tests

[alecandido]

Sorry for the delay: I'm also able to install with Poetry and run tests. And just one of them is failing.

        log.error(message)
>       raise exception(message)
E       ValueError: Backend qulacs is not available. To check which backends are installed use `qibo.list_available_backends()`.

src/qibo/config.py:46: ValueError
--------------------------------------------------------------------------------------------- Captured stderr call ---------------------------------------------------------------------------------------------
[Qibo 0.2.9|ERROR|2024-06-03 15:35:25]: Backend qulacs is not available. To check which backends are installed use `qibo.list_available_backends()`.
---------------------------------------------------------------------------------------------- Captured log call -----------------------------------------------------------------------------------------------
ERROR    qibo.config:config.py:45 Backend qulacs is not available. To check which backends are installed use `qibo.list_available_backends()`.

I will also have a look to the CI asap.

[BrunoLiegiBastonLiegi]

Yeah thanks for spotting this, I forgot to add qulacs to the QIBO_NATIVE_BACKENDS global var. It should be fixed now.

[BrunoLiegiBastonLiegi]

By the way, I think the problem with 3.9 is always related to some missing dependecies, namely the c++ boost library. Could it be that the qulacs wheel they distribute for python3.9 is missing it? However, that would be weird, beacuse I remember we did not have problem with 3.9 before.

[alecandido]

The problem is a distribution problem: Qulacs is not distributing py3.9 wheels for MacOS ARM

https://pypi.org/project/qulacs/0.6.4.1/#files
The asymmetry on their side is causing the asymmetry in our CI (which, only for py3.9 ARM, is attempting to build the wheel).

The missing library should have not been a difference among different Python versions (at least to first order approximation).