Removing unnecessary identity operation from exponential_map() #373
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
the hardcoded implementation of the identity operation on the 0th qubit unnecessarily inflates circuits (even if it gets removed later in the compiler) and leads to problems when using the new ``embedding`` argument in the QAOA instance
|
@willzeng @ecp-rigetti and others. I think think there was a conscious decision to keep these phase factors in. It's unfortunate that it always hits the 0th qubit though. |
|
@mpharrigan I think it's good to remove. It was original included for testing purposes. I agree with @markf94 that these terms only inflate the circuit. |
|
I'm happy to see the debug |
|
A year and a half later, I don't recall what people cared about this phase factor for, and I'm inclined to re-open this PR for consideration. This PR doesn't get rid of the phase factor in the PauliSum itself — just in the conversion of its exponentiation to a circuit. Any interested party could still look at the PauliSum directly to discover the phase factor. |
|
@markf94 If you update this to also kill the |
2 tasks
jlapeyre
added a commit
that referenced
this pull request
Feb 25, 2020
* exponential_map of the identity applies a PHASE gate and its inverse. This was apparently for debugging purposes. This PR replaces the PHASE gates with an empty Program. * This PR moves conditionals on data that is closed over from inside the closure to outside. That is, the gate that is exponentiated is checked when the closure is created, but not when it is executed. Closes #1055. This PR obsoletes PR #373.
jlapeyre
added a commit
that referenced
this pull request
Feb 25, 2020
* exponential_map of the identity applies a PHASE gate and its inverse. This was apparently for debugging purposes. This PR replaces the PHASE gates with an empty Program. * This PR moves conditionals on data that is closed over from inside the closure to outside. That is, the gate that is exponentiated is checked when the closure is created, but not when it is executed. Closes #1055. This PR obsoletes PR #373.
jlapeyre
added a commit
that referenced
this pull request
Feb 25, 2020
* exponential_map of the identity applies a PHASE gate and its inverse. This was apparently for debugging purposes. This PR replaces the PHASE gates with an empty Program. * This PR moves conditionals on data that is closed over from inside the closure to outside. That is, the gate that is exponentiated is checked when the closure is created, but not when it is executed. Closes #1055. This PR obsoletes PR #373.
jlapeyre
added a commit
that referenced
this pull request
Feb 25, 2020
* exponential_map of the identity applies a PHASE gate and its inverse. This was apparently for debugging purposes. This PR replaces the PHASE gates with an empty Program. * This PR moves conditionals on data that is closed over from inside the closure to outside. That is, the gate that is exponentiated is checked when the closure is created, but not when it is executed. Closes #1055. This PR obsoletes PR #373.
jlapeyre
added a commit
that referenced
this pull request
Feb 25, 2020
* exponential_map of the identity applies a PHASE gate and its inverse. This was apparently for debugging purposes. This PR replaces the PHASE gates with an empty Program. * This PR moves conditionals on data that is closed over from inside the closure to outside. That is, the gate that is exponentiated is checked when the closure is created, but not when it is executed. Closes #1055. This PR obsoletes PR #373.
jlapeyre
added a commit
that referenced
this pull request
Feb 25, 2020
* exponential_map of the identity applies a PHASE gate and its inverse. This was apparently for debugging purposes. This PR replaces the PHASE gates with an empty Program. * This PR moves conditionals on data that is closed over from inside the closure to outside. That is, the gate that is exponentiated is checked when the closure is created, but not when it is executed. Closes #1055. This PR obsoletes PR #373.
jlapeyre
added a commit
that referenced
this pull request
Feb 26, 2020
* exponential_map of the identity applies a PHASE gate and its inverse. This was apparently for debugging purposes. This PR replaces the PHASE gates with an empty Program. * This PR moves conditionals on data that is closed over from inside the closure to outside. That is, the gate that is exponentiated is checked when the closure is created, but not when it is executed. Closes #1055. This PR obsoletes PR #373.
|
See #1182 |
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.
The hardcoded implementation of the identity operation on the
0th qubit unnecessarily inflates circuits (even if it gets removed
later in the compiler) and leads to problems when using the new
embeddingargument in the QAOA instance (see PR #143 in grove)