120 lines
6.3 KiB
Plaintext
120 lines
6.3 KiB
Plaintext
---
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title: ElidePermutations (v1.2)
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description: API reference for qiskit.transpiler.passes.ElidePermutations in qiskit v1.2
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in_page_toc_min_heading_level: 1
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python_api_type: class
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python_api_name: qiskit.transpiler.passes.ElidePermutations
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---
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# ElidePermutations
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<Class id="qiskit.transpiler.passes.ElidePermutations" isDedicatedPage={true} github="https://github.com/Qiskit/qiskit/tree/stable/1.2/qiskit/transpiler/passes/optimization/elide_permutations.py#L26-L114" signature="qiskit.transpiler.passes.ElidePermutations(*args, **kwargs)" modifiers="class">
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Bases: [`TransformationPass`](qiskit.transpiler.TransformationPass "qiskit.transpiler.basepasses.TransformationPass")
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Remove permutation operations from a pre-layout circuit
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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`](qiskit.dagcircuit.DAGCircuit "qiskit.dagcircuit.DAGCircuit") and when a [`SwapGate`](qiskit.circuit.library.SwapGate "qiskit.circuit.library.SwapGate") or [`PermutationGate`](qiskit.circuit.library.PermutationGate "qiskit.circuit.library.PermutationGate") are encountered it permutes the virtual qubits in the circuit and removes the swap gate. This will effectively remove any `SwapGate`s 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.
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For tracking purposes this pass sets 3 values in the property set if there are any [`SwapGate`](qiskit.circuit.library.SwapGate "qiskit.circuit.library.SwapGate") or [`PermutationGate`](qiskit.circuit.library.PermutationGate "qiskit.circuit.library.PermutationGate") objects in the circuit and the pass isn’t a no-op.
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* `original_layout`: The trivial [`Layout`](qiskit.transpiler.Layout "qiskit.transpiler.Layout") for the input to this pass being run
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* **`original_qubit_indices`: The mapping of qubit objects to positional indices for the state**
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of the circuit as input to this pass.
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* **`virtual_permutation_layout`: A [`Layout`](qiskit.transpiler.Layout "qiskit.transpiler.Layout") object mapping input qubits to the output**
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state after eliding permutations.
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These three properties are needed for the transpiler to track the permutations in the out [`QuantumCircuit.layout`](qiskit.circuit.QuantumCircuit#layout "qiskit.circuit.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
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## Attributes
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### is\_analysis\_pass
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<Attribute id="qiskit.transpiler.passes.ElidePermutations.is_analysis_pass">
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Check if the pass is an analysis pass.
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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.
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</Attribute>
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### is\_transformation\_pass
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<Attribute id="qiskit.transpiler.passes.ElidePermutations.is_transformation_pass">
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Check if the pass is a transformation pass.
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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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</Attribute>
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## Methods
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### execute
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<Function id="qiskit.transpiler.passes.ElidePermutations.execute" github="https://github.com/Qiskit/qiskit/tree/stable/1.2/qiskit/transpiler/basepasses.py#L189-L211" signature="execute(passmanager_ir, state, callback=None)">
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Execute optimization task for input Qiskit IR.
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**Parameters**
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* **passmanager\_ir** ([*Any*](https://docs.python.org/3/library/typing.html#typing.Any "(in Python v3.13)")) – Qiskit IR to optimize.
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* **state** ([*PassManagerState*](qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")) – State associated with workflow execution by the pass manager itself.
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* **callback** ([*Callable*](https://docs.python.org/3/library/collections.abc.html#collections.abc.Callable "(in Python v3.13)") *| None*) – A callback function which is caller per execution of optimization task.
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**Returns**
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Optimized Qiskit IR and state of the workflow.
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**Return type**
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[tuple](https://docs.python.org/3/library/stdtypes.html#tuple "(in Python v3.13)")\[[*Any*](https://docs.python.org/3/library/typing.html#typing.Any "(in Python v3.13)"), [qiskit.passmanager.compilation\_status.PassManagerState](qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")]
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</Function>
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### name
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<Function id="qiskit.transpiler.passes.ElidePermutations.name" github="https://github.com/Qiskit/qiskit/tree/stable/1.2/qiskit/passmanager/base_tasks.py#L68-L70" signature="name()">
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Name of the pass.
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**Return type**
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[str](https://docs.python.org/3/library/stdtypes.html#str "(in Python v3.13)")
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</Function>
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### run
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<Function id="qiskit.transpiler.passes.ElidePermutations.run" github="https://github.com/Qiskit/qiskit/tree/stable/1.2/qiskit/transpiler/passes/optimization/elide_permutations.py#L54-L114" signature="run(dag)">
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Run the ElidePermutations pass on `dag`.
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**Parameters**
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**dag** ([*DAGCircuit*](qiskit.dagcircuit.DAGCircuit "qiskit.dagcircuit.DAGCircuit")) – the DAG to be optimized.
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**Returns**
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the optimized DAG.
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**Return type**
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[DAGCircuit](qiskit.dagcircuit.DAGCircuit "qiskit.dagcircuit.DAGCircuit")
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</Function>
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### update\_status
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<Function id="qiskit.transpiler.passes.ElidePermutations.update_status" github="https://github.com/Qiskit/qiskit/tree/stable/1.2/qiskit/transpiler/basepasses.py#L213-L221" signature="update_status(state, run_state)">
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Update workflow status.
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**Parameters**
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* **state** ([*PassManagerState*](qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")) – Pass manager state to update.
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* **run\_state** (*RunState*) – Completion status of current task.
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**Returns**
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Updated pass manager state.
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**Return type**
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[*PassManagerState*](qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")
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</Function>
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</Class>
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