qasm_to_circuit method not supporting u1, u2, u3 gate

[Zhaoyilunnn]

Problem

qasm_to_circuit method not supporting u1, u2, u3 gate

Root Cause

from_openqasm method support u1, u2, u3 gate. (code pointer).

However, u1, u2, u3 gates are not independent classes and are not supported in dagcircuits. (code pointer)

Solution

TBD

Suggestion

Suggest not to deprecate from_openqasm method in QuantumCircuit class, because we need to ensure backward compatibility. We can throw a deprecated warning to guide users to gradually trans to new methods in qfasm.