Fix expansion of fragments tapes containing no MeasureNode
#2223
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Thanks @anthayes92! Good spot! My only question is whether the bugfix should live in the _get_measurements helper function.
pennylane/transforms/qcut.py
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| if len(group) > 0: | ||
| measurements = _get_measurements(group, tape.measurements) | ||
| # This ensures the measurements of the original tape are carried over to the | ||
| # following tape configurations in the absence of any MeasureNodes in the fragment | ||
| else: | ||
| measurements = tape.measurements |
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We could put this logic in _get_measurements, i.e., the first thing we do is:
if len(group) == 0:
return measurements
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Nice idea! I've moved it in this commit 1129df6
Codecov Report
@@ Coverage Diff @@
## master #2223 +/- ##
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Coverage 99.26% 99.26%
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Files 231 231
Lines 18241 18243 +2
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+ Hits 18107 18109 +2
Misses 134 134
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Context:
Fragment tapes of cut circuit need to be expanded to multiple configurations in order to execute and recombine results. However, the observables of fragments tapes containing no
MeasureNodewere being lost.Description of the Change:
This PR fixes the logic so that measurements of such fragments persist across the following configurations
Benefits:
Fixes broken pipeline for this specific case
Related GitHub Issues:
Blocker for #2216