Description of changes:
Update the BraketProgramContext to extend the changes introduced in https://github.com/amazon-braket/amazon-braket-default-simulator-python/pull/266, which provide a classical register index to the BraketProgramContext add_measure method when a measurement assignment is used in an OpenQASM program (e.g. b[1] = measure q[1];). This allows translations to and from Braket BDK Circuits and OpenQASM to be consistent with regards to classical register indices used in measurement assignments as currently, these indices are discarded entirely.
Additionally, updating the _measure_targets array in the Circuit object was moved to the add_instruction method from the _add_measure method. This is because users of the Circuit class are able to add measurement instructions via the add_instruction method, but _measure_targets will not be updated to reflect qubits used in the measurement. This results in incorrect behavior when using to_ir to take a circuit with measurements added via add_instruction method calls to OpenQASM as to_ir will check the _measure_targets variable to see if any qubits are measured, see that the list is empty, and apply a measurement to all the qubits in the circuit, including those already measured via the original add_instruction method calls.
Testing done:
A round trip test was added to verify that classical register assignments are persisted when going from BDK Circuit to OpenQASM and back to BDK Circuit via the to_ir and from_ir methods; this is similarly checked when going from OpenQASM to BDK Circuit back to OpenQASM.
Merge Checklist
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Issue #, if available:
1004
Description of changes: Update the BraketProgramContext to extend the changes introduced in https://github.com/amazon-braket/amazon-braket-default-simulator-python/pull/266, which provide a classical register index to the BraketProgramContext
add_measuremethod when a measurement assignment is used in an OpenQASM program (e.g.b[1] = measure q[1];). This allows translations to and from Braket BDK Circuits and OpenQASM to be consistent with regards to classical register indices used in measurement assignments as currently, these indices are discarded entirely.Additionally, updating the
_measure_targetsarray in theCircuitobject was moved to theadd_instructionmethod from the_add_measuremethod. This is because users of the Circuit class are able to add measurement instructions via theadd_instructionmethod, but_measure_targetswill not be updated to reflect qubits used in the measurement. This results in incorrect behavior when usingto_irto take a circuit with measurements added viaadd_instructionmethod calls to OpenQASM asto_irwill check the_measure_targetsvariable to see if any qubits are measured, see that the list is empty, and apply a measurement to all the qubits in the circuit, including those already measured via the originaladd_instructionmethod calls.Testing done:
A round trip test was added to verify that classical register assignments are persisted when going from BDK Circuit to OpenQASM and back to BDK Circuit via the
to_irandfrom_irmethods; this is similarly checked when going from OpenQASM to BDK Circuit back to OpenQASM.Merge Checklist
Put an
xin the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your pull request.General
Tests
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