Fix multi-controlled gates in name mapping #2326
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These gates could not be instantiated due to a mismatch in the number of qubits with the base gate.
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Summary
MCSXGate,MCYGate,MCZGate,MCRXGate,MCRYGate,MCRZGate,MCU3Gate,MCUGate, andMCSwapGatecan not be instantiated due to a mismatch in the number of qubits with the base gate:Details and comments
I came across this issue while writing a unit test for Qiskit/qiskit#13952.
Commit doichanj@4587384 (pull #1995) changed the base gates of these gates from non-controlled gates into singly controlled gates, which means there is one qubit too much in the base gate.
An alternative solution would be to reduce
num_ctrl_qubitsby one when callingControlledGate.__init__(), but then the multi-controlled gates can only be created for two or more control qubits and one would need to extract the last qubit from the control state to pass it to the base gate.