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class ApplyLayout(*args, **kwargs)

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Bases: qiskit.transpiler.basepasses.TransformationPass

Transform a circuit with virtual qubits into a circuit with physical qubits.

Transforms a DAGCircuit with virtual qubits into a DAGCircuit with physical qubits by applying the Layout given in property_set. Requires either of passes to set/select Layout, e.g. SetLayout, TrivialLayout. Assumes the Layout has full physical qubits.

If a post layout pass is run and sets the post_layout property set field with a new layout to use after ApplyLayout has already run once this pass will compact the layouts so that we apply original_virtual -> existing_layout -> new_layout -> new_physical so that the output circuit and layout combination become: original_virtual -> new_physical



Return the name of the pass.


Run the ApplyLayout pass on dag.


dag (DAGCircuit) – DAG to map.


A mapped DAG (with physical qubits).

Return type



TranspilerError – if no layout is found in property_set or no full physical qubits.



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).

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