Fix ResetGate to work with MPS, StabilizerSampler #4765
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
cc @95-martin-orion since you seem to be on a mission today |
95-martin-orion
requested changes
Dec 28, 2021
| if args.state._measure(axe, args.prng): | ||
| ops.X._act_on_(args, qubits) | ||
| return True | ||
| class PlusGate(raw_types.Gate): |
There was a problem hiding this comment.
[No change needed] Adding a new internal gate class just for this interaction feels heavy-handed, but I guess it's necessary so we can use act_on with the other simulator types?
There was a problem hiding this comment.
I was just thinking, maybe it makes sense to have a public PlusGate? This code is copied and pasted in several places, mostly tests.
There was a problem hiding this comment.
Just saw the test from your other comment. I wouldn't be opposed to a public PlusGate (there might even be hardware examples of such a gate), but it can be added in a separate PR.
95-martin-orion
approved these changes
Dec 28, 2021
95-martin-orion
added
the
automerge
CirqBot
added
the
front_of_queue_automerge
CirqBot
removed
automerge
MichaelBroughton
pushed a commit
to MichaelBroughton/Cirq
that referenced
this pull request
Jan 22, 2022
This abstracts the implementation of ResetGate to be a measurment and then a PlusGate with an offset that gets the qubit back to the zero state (for 2-dimensional qubits, this is equivalent to X iff measurement==1). This allows Reset to work for all simulators, not just the specific ones whose cases were implemented in the existing code. There is a special consideration for density-matrix-like simulators. For these, we do not want to actually perform the measurement, as a density matrix can represent the mixed state of all measurement results. Performing the measurement would lose that information. Therefore, here we add a `can_represent_mixed_states` property to the ActOnArgs, and if that is true, then we allow the simulator to fall back to its own apply_channel implementation. This new property allows other density-matrix-like state representations (say a superoperator simulator) to adopt the same behavior without having to update `ResetGate._act_on_`.
rht
pushed a commit
to rht/Cirq
that referenced
this pull request
May 1, 2023
This abstracts the implementation of ResetGate to be a measurment and then a PlusGate with an offset that gets the qubit back to the zero state (for 2-dimensional qubits, this is equivalent to X iff measurement==1). This allows Reset to work for all simulators, not just the specific ones whose cases were implemented in the existing code. There is a special consideration for density-matrix-like simulators. For these, we do not want to actually perform the measurement, as a density matrix can represent the mixed state of all measurement results. Performing the measurement would lose that information. Therefore, here we add a `can_represent_mixed_states` property to the ActOnArgs, and if that is true, then we allow the simulator to fall back to its own apply_channel implementation. This new property allows other density-matrix-like state representations (say a superoperator simulator) to adopt the same behavior without having to update `ResetGate._act_on_`.
harry-phasecraft
pushed a commit
to PhaseCraft/Cirq
that referenced
this pull request
Oct 31, 2024
This abstracts the implementation of ResetGate to be a measurment and then a PlusGate with an offset that gets the qubit back to the zero state (for 2-dimensional qubits, this is equivalent to X iff measurement==1). This allows Reset to work for all simulators, not just the specific ones whose cases were implemented in the existing code. There is a special consideration for density-matrix-like simulators. For these, we do not want to actually perform the measurement, as a density matrix can represent the mixed state of all measurement results. Performing the measurement would lose that information. Therefore, here we add a `can_represent_mixed_states` property to the ActOnArgs, and if that is true, then we allow the simulator to fall back to its own apply_channel implementation. This new property allows other density-matrix-like state representations (say a superoperator simulator) to adopt the same behavior without having to update `ResetGate._act_on_`.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This abstracts the implementation of ResetGate to be a measurment and then a PlusGate with an offset that gets the qubit back to the zero state (for 2-dimensional qubits, this is equivalent to X iff measurement==1).
This allows Reset to work for all simulators, not just the specific ones whose cases were implemented in the existing code.
There is a special consideration for density-matrix-like simulators. For these, we do not want to actually perform the measurement, as a density matrix can represent the mixed state of all measurement results. Performing the measurement would lose that information. Therefore, here we add a
can_represent_mixed_statesproperty to the ActOnArgs, and if that is true, then we allow the simulator to fall back to its own apply_channel implementation. This new property allows other density-matrix-like state representations (say a superoperator simulator) to adopt the same behavior without having to updateResetGate._act_on_.