Implements native support for Sparse Hamiltonians expval() calculation with Kokkos

[AmintorDusko]

Context:

This PR implements native support for sparse Hamiltonians expval calculation.
Sparse operations are offloaded to Kokkos.

Description of the Change:

Add native support for the calculation of sparse Hamiltonians' expectation values.

Benefits:

Performant calculation with Pennylane-Lightning

Possible Drawbacks:

Not that I'm aware of.

Related GitHub Issues:

Not that I'm aware of.

[github-actions]

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[github-actions]

Test Report (C++) on Ubuntu

           1 files  ±  0             1 suites  ±0   1s ⏱️ -1s
       865 tests +11         865 ✔️ +11  0 💤 ±0  0 ❌ ±0 
228 763 runs  +21  228 763 ✔️ +21  0 💤 ±0  0 ❌ ±0 

Results for commit ef86272. ± Comparison against base commit e4db7f1.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

Merging #283 (ef86272) into master (e4db7f1) will increase coverage by 0.19%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #283      +/-   ##
==========================================
+ Coverage   99.24%   99.44%   +0.19%     
==========================================
  Files          29       30       +1     
  Lines        3330     3410      +80     
==========================================
+ Hits         3305     3391      +86     
+ Misses         25       19       -6     

Impacted Files	Coverage Δ
pennylane_lightning/_version.py	100.00% <100.00%> (ø)
pennylane_lightning/lightning_qubit.py	100.00% <100.00%> (ø)
pennylane_lightning/src/simulator/Measures.hpp	100.00% <100.00%> (+2.66%)	⬆️
pennylane_lightning/src/util/Kokkos_Sparse.hpp	100.00% <100.00%> (ø)
...nnylane_lightning/src/simulator/StateVectorRaw.hpp	88.23% <0.00%> (-11.77%)	⬇️
pennylane_lightning/src/gates/GateUtil.cpp	100.00% <0.00%> (ø)
pennylane_lightning/src/gates/GateUtil.hpp	100.00% <0.00%> (ø)
pennylane_lightning/src/util/RuntimeInfo.cpp	100.00% <0.00%> (ø)
pennylane_lightning/src/util/RuntimeInfo.hpp	100.00% <0.00%> (ø)
...ennylane_lightning/src/algorithms/JacobianTape.hpp	100.00% <0.00%> (ø)
... and 9 more

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[chaeyeunpark]

Hi @AmintorDusko, I think Kokkos does not support MSVC. We may need to try clang-cl instead... I will ping you on slack.

[AmintorDusko]

Hi @AmintorDusko, I think Kokkos does not support MSVC. We may need to try clang-cl instead... I will ping you on slack.

Yes. Its looks like it! Thank you very much @chaeyeunpark!
Also, your add_kokkos branch was quite useful!
Thank you for looking into it before me!

[mlxd]

Hey Amintor, I have a few more comments/questions.

[mlxd]

Awesome work on this Amintor! One last thing we need is to update the license statement at the end of the Lightning README to indicate we are using Kokkos under the BSD license (see Jet's statement here for an example).

[mlxd]

💯

[maliasadi]

Hey @AmintorDusko. great job! 💯 Sorry for this late review; I was thinking this one is still work-in-progress 🙁 As this one already merged and you also merged the follow-up PR (#296). I'll go with a few general comments to be applied for later...