Greedy vs Simple Qubit Ancilla Manager decompose bug with prepareuniformsuperposition

[akurlej]

Greedy qubit manager fails with a duplicate QID on a CNOT in the LessThanConstant , SimpleQubitManager works without issue.

Issue occurs with current release of qualtran (0.2.0)

Code to reproduce:

import cirq
from qualtran.bloqs.prepare_uniform_superposition import PrepareUniformSuperposition

n=3
target = cirq.NamedQubit.range((n-1).bit_length(),prefix='target')
control = [cirq.NamedQubit('control')]
circuit_error = cirq.inverse(cirq.Circuit(PrepareUniformSuperposition(n,cvs=(0,)).on_registers(ctrl=control,target=target)))

#Greedy fails, simple works
gqm = cirq.GreedyQubitManager(prefix="_ancilla", maximize_reuse=True)
#gqm = cirq.SimpleQubitManager(prefix="_ancilla")
cirq.decompose(circuit_error,context = cirq.DecompositionContext(gqm))

[rroodll]

@mpharrigan is there any update on this one? Thanks
btw - sent an email to your outlook addr when you get a chance

[tanujkhattar]

@akurlej @rroodll This is now fixed. Please let us know if you still run into any issues. Thanks for reporting and apologies it took so long to fix!

[rroodll]

Thanks @tanujkhattar! This is great. One of us will pull the latest and give it a test.