Fix mapper issue #342 #347
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Wonderful, thanks @ajavadia for tackling the long-standing bug! I'm not closing the related issues yet (other than the one that will be automatically-closed when merging the PR) with the idea of officially going through them once the fix gets to the stable version, thanks for listing them! 👍 |
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This was referenced Apr 16, 2018
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Jul 30, 2019
* get_qubits return in order * added test to reproduce emoticon mapping issue * test mapping of already-conforming circuits * test gate after measure in quantumprogram
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The issue described in #342 is fixed (mapper bug alters already conforming circuits, and inserts operation after measurement).
This PR also resolves several other bug reports about mapper behavior:
Description
The default layout, if none is provided, is a layout of circuit qubit i to device qubit i. This is reasonable since many users will hand optimize circuits and create already-conforming gates, or would like to map qubits to exact same qubits on the device.
If compilation is being performed for a real backend, the compiler inserts barriers before measurements to ensure they do not move before gates.
Motivation and Context
How Has This Been Tested?
make testAlso added new tests in
test_mapper.pyandtest_quantumprogram.py. So in the likely event of changing the mapper to another, faster code base, we will hopefully not encounter these issues.Screenshots (if appropriate):
Types of changes
Checklist: