Fix transforms that error with non-commuting measurements #5424
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…nnyLaneAI/pennylane into non-commuting-expanding-fixes
As name says. --------- Co-authored-by: Astral Cai <astral.cai@xanadu.ai>
**Context:** Some newly added test cases failing with legacy opmath **Description of the Change:** Skip these tests if new opmath is disabled: `test_measure_identity_no_wires` in `tests/devices/qubit/test_measure.py` `test_identity_on_no_wires_with_other_observables` in `tests/devices/qubit/test_sampling.py` `test_observables_on_no_wires_coeffs` in `tests/pauli/grouping/test_pauli_group_observables.py` `test_multiple_hamiltonian_expansion_finite_shots` in `tests/test_qnode_legacy.py` **Related Shortcut Issues:** [sc-62144] [sc-62143]
**Context:** 1. `Hamiltonian` does not remove ops from queue if `simplify=True` 2. `TrotterProduct` does not remove `Hamiltonian` **Description of the Change:** Manually dequeue said ops **Related Shortcut Issues:** [sc-62142] --------- Co-authored-by: Mudit Pandey <mudit.pandey@xanadu.ai>
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------------------------------------------------------------------------------------------------------------
**Context:**
`qml.counts` does not return the same `keys` with `dynamic_one_shot` and
`defer_measurements`.
**Description of the Change:**
Cast `keys` to the type produced by `concretize`.
**Benefits:**
Consistent `keys`.
**Possible Drawbacks:**
Slight (likely unnoticeable) performance decrease since `NDArray` object
cannot be preallocated.
**Related GitHub Issues:**
#5566
---------
Co-authored-by: David Wierichs <david.wierichs@xanadu.ai>
albi3ro
commented
Apr 30, 2024
- [x] Fix last open bug or open issue **Context:** Docs get out of sync over time. In particular, the output shape of gradient transforms applied to QNodes was changed in #4945 but not updated in the docs. **Description of the Change:** Update examples in docs of `qml.gradients` module. Also updates the `qml.kernels` docs, with a few very small changes. **Benefits:** **Possible Drawbacks:** **Related GitHub Issues:**
2 very minor corrections to documentation added in this release
**Context:** Fixes latest failures in the legacy opmath tests in the plugin test matrix. **Description of the Change:** 1. `convert_to_opmath` now dequeues the original op. 2. Skip test with `I()` when new opmath is disabled.
albi3ro
commented
Apr 30, 2024
Codecov ReportAll modified and coverable lines are covered by tests ✅
Additional details and impacted files@@ Coverage Diff @@
## master #5424 +/- ##
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- Coverage 99.69% 99.68% -0.01%
==========================================
Files 412 412
Lines 38641 38385 -256
==========================================
- Hits 38523 38264 -259
- Misses 118 121 +3 ☔ View full report in Codecov by Sentry. |
dwierichs
requested changes
May 6, 2024
albi3ro
commented
May 6, 2024
Co-authored-by: David Wierichs <david.wierichs@xanadu.ai>
dwierichs
approved these changes
May 7, 2024
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Nice upgrade using existing code @albi3ro, thanks!
I like @lillian542's idea to modify the error message, otherwise good to go for me!
mudit2812
added a commit
that referenced
this pull request
May 8, 2024
**Context:** `tape.expand` will error out if the tape has any non-commuting measurements present. But multiple transforms that don't care about measurements at all use it to decompose to a target gate set. Even when `expand_measurements=False`, `tape.expand` requires measurements to be commuting, or composite observables. And this is a core behavior of `tape.expand` that people might rely on. It's not as much a bug as a problematic feature. AKA load-bearing bug. Fortunately, we now have `qml.devices.preprocess.decompose`, which is a transform that is capable of decomposing to a target gateset. While yes, this transform is in the `devices` module, so using it is introducing a cross-module dependency in a direction that we do not want, it gets the job done. I would call this a sign that we should potentially consider moving it into the `transforms` module and making it's import path more accessible. **Description of the Change:** Use `decompose` instead of `tape.expand` in a variety of transforms. **Benefits:** These transforms now allow non-commuting measurements through. **Possible Drawbacks:** We still have other transforms still relying on `tape.expand`. But we can investigate those another day. Introducing a cross-module dependency in a direction we don't want a dependency. This could be fixed by moving `decompose` to the transforms module, but that is a problem for another day. **Related GitHub Issues:** Fixes #5401 Fixes #5316 [sc-58086] [sc-59118] --------- Co-authored-by: Mudit Pandey <mudit.pandey@xanadu.ai> Co-authored-by: Astral Cai <astral.cai@xanadu.ai> Co-authored-by: Vincent Michaud-Rioux <vincentm@nanoacademic.com> Co-authored-by: David Wierichs <david.wierichs@xanadu.ai> Co-authored-by: lillian542 <38584660+lillian542@users.noreply.github.com>
dwierichs
added a commit
that referenced
this pull request
May 14, 2024
**Context:** The first example in the docs of `qml.transforms.insert` was reported to not be working [here](https://discuss.pennylane.ai/t/qml-device-error-with-qiskit-aer/4556/9). Other examples also do not work. **Description of the Change:** This PR changes the docs examples to work. It also replicates the change in #5424 to use `devices.preprocess.decompose` instead of `tape.expand`, adding support for non-commuting measurements (which is unrelated to the transform anyways), and removing the need for a custom error to be raised. **Benefits:** Docs examples work. Non-commuting measurements support. **Possible Drawbacks:** Similar to #5424, this introduces cross-dependency to the devices module. **Related GitHub Issues:**
Shiro-Raven
pushed a commit
that referenced
this pull request
May 15, 2024
**Context:** The first example in the docs of `qml.transforms.insert` was reported to not be working [here](https://discuss.pennylane.ai/t/qml-device-error-with-qiskit-aer/4556/9). Other examples also do not work. **Description of the Change:** This PR changes the docs examples to work. It also replicates the change in #5424 to use `devices.preprocess.decompose` instead of `tape.expand`, adding support for non-commuting measurements (which is unrelated to the transform anyways), and removing the need for a custom error to be raised. **Benefits:** Docs examples work. Non-commuting measurements support. **Possible Drawbacks:** Similar to #5424, this introduces cross-dependency to the devices module. **Related GitHub Issues:**
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Context:
tape.expandwill error out if the tape has any non-commuting measurements present. But multiple transforms that don't care about measurements at all use it to decompose to a target gate set. Even whenexpand_measurements=False,tape.expandrequires measurements to be commuting, or composite observables. And this is a core behavior oftape.expandthat people might rely on. It's not as much a bug as a problematic feature. AKA load-bearing bug.Fortunately, we now have
qml.devices.preprocess.decompose, which is a transform that is capable of decomposing to a target gateset. While yes, this transform is in thedevicesmodule, so using it is introducing a cross-module dependency in a direction that we do not want, it gets the job done. I would call this a sign that we should potentially consider moving it into thetransformsmodule and making it's import path more accessible.Description of the Change:
Use
decomposeinstead oftape.expandin a variety of transforms.Benefits:
These transforms now allow non-commuting measurements through.
Possible Drawbacks:
We still have other transforms still relying on
tape.expand. But we can investigate those another day.Introducing a cross-module dependency in a direction we don't want a dependency. This could be fixed by moving
decomposeto the transforms module, but that is a problem for another day.Related GitHub Issues:
Fixes #5401 Fixes #5316 [sc-58086] [sc-59118]