Skip to main contentIBM Quantum Documentation


class qiskit.transpiler.passes.ElidePermutations(*args, **kwargs)

GitHub(opens in a new tab)

Bases: TransformationPass

Remove permutation operations from a pre-layout circuit

This pass is intended to be run before a layout (mapping virtual qubits to physical qubits) is set during the transpilation pipeline. This pass iterates over the DAGCircuit and when a SwapGate or PermutationGate are encountered it permutes the virtual qubits in the circuit and removes the swap gate. This will effectively remove any SwapGates or PermutationGate in the circuit prior to running layout. If this pass is run after a layout has been set it will become a no-op (and log a warning) as this optimization is not sound after physical qubits are selected and there are connectivity constraints to adhere to.

For tracking purposes this pass sets 3 values in the property set if there are any SwapGate or PermutationGate objects in the circuit and the pass isn’t a no-op.

  • original_layout: The trivial Layout for the input to this pass being run

  • original_qubit_indices: The mapping of qubit objects to positional indices for the state

    of the circuit as input to this pass.

  • virtual_permutation_layout: A Layout object mapping input qubits to the output

    state after eliding permutations.

These three properties are needed for the transpiler to track the permutations in the out QuantumCircuit.layout attribute. The elision of permutations is equivalent to a final_layout set by routing and all three of these attributes are needed in the case



Check if the pass is an analysis pass.

If the pass is an AnalysisPass, that means that the pass can analyze the DAG and write the results of that analysis in the property set. Modifications on the DAG are not allowed by this kind of pass.


Check if the pass is a transformation pass.

If the pass is a TransformationPass, that means that the pass can manipulate the DAG, but cannot modify the property set (but it can be read).



execute(passmanager_ir, state, callback=None)

GitHub(opens in a new tab)

Execute optimization task for input Qiskit IR.



Optimized Qiskit IR and state of the workflow.

Return type

tuple(opens in a new tab)[Any(opens in a new tab), qiskit.passmanager.compilation_status.PassManagerState]



GitHub(opens in a new tab)

Name of the pass.

Return type

str(opens in a new tab)



GitHub(opens in a new tab)

Run the ElidePermutations pass on dag.


dag (DAGCircuit) – the DAG to be optimized.


the optimized DAG.

Return type



update_status(state, run_state)

GitHub(opens in a new tab)

Update workflow status.


  • state (PassManagerState) – Pass manager state to update.
  • run_state (RunState) – Completion status of current task.


Updated pass manager state.

Return type


Was this page helpful?
Report a bug or request content on GitHub.