Fix derivatives of merge_rotations and single_qubit_fusion
#6033
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…and test for singular points of Jacobian
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Codecov ReportAll modified and coverable lines are covered by tests ✅
Additional details and impacted files@@ Coverage Diff @@
## master #6033 +/- ##
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- Coverage 99.66% 99.65% -0.01%
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Files 432 432
Lines 41996 41691 -305
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- Hits 41855 41549 -306
- Misses 141 142 +1 ☔ View full report in Codecov by Sentry. |
Co-authored-by: Vincent Michaud-Rioux <vincent.michaud-rioux@xanadu.ai>
Co-authored-by: Korbinian Kottmann <43949391+Qottmann@users.noreply.github.com>
Co-authored-by: Thomas R. Bromley <49409390+trbromley@users.noreply.github.com>
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Nice PR @dwierichs . Looks good to me! I'm suggesting a couple changes, which you can accept or reject as you see fit.
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Is this targeting the correct base branch as is? 😬 |
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Haha, sorry @Qottmann . Yes the base branch is right, but I merged master into both branches, but only pushed it here and not on the |
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Good job @dwierichs
Don't see anything suspicious and appreciate the simplifications of the code.
dwierichs
added
the
merge-ready ✔️
Context:
As reported in #5715,
merge_rotationsandsingle_qubit_fusionhave problems with differentiability at specific points.#6031 takes care of upgrading the Rot-angle fusion to only ever return NaNs at mathematically non-differentiable points, rather than wrong results.
However, the transforms add additional points, based on internal optimizations, where the derivative is flawed.
Description of the Change:
This PR fixes the flawed derivatives caused by the code of the transforms themselves.
Benefits:
Fixes derivatives of
merge_rotationsandsingle_qubit_fusion(where mathematically defined)Possible Drawbacks:
N/A
Related GitHub Issues:
Fixes another part of #5715, still not all of it.