# CustomF2QLayout

### *class* CustomF2QLayout(layout)

Sets the user-provided [`F2QLayout`](qiskit_fermions.transpiler.F2QLayout.html.md#qiskit_fermions.transpiler.F2QLayout) in the transpiler.

Bases: [`GenericPass`](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.passmanager.GenericPass)[[`DAGCircuit`](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.dagcircuit.DAGCircuit), [`DAGCircuit`](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.dagcircuit.DAGCircuit)]

This pass simply populates the `f2q_layout` field of the
[`property_set`](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.passmanager.PassManagerState#property_set), with the value of [`layout`](#qiskit_fermions.transpiler.passes.CustomF2QLayout.layout).

#### NOTE
It is the user’s responsibility to ensure that subsequently used transpilation passes (and
plugins) are configured to adhere to this [`F2QLayout`](qiskit_fermions.transpiler.F2QLayout.html.md#qiskit_fermions.transpiler.F2QLayout)
correctly.

Initializing this transpiler pass can be done with the arguments listed below.

* **Parameters:**
  **layout** ([*F2QLayout*](qiskit_fermions.transpiler.F2QLayout.html.md#qiskit_fermions.transpiler.F2QLayout)) – the custom `f2q_layout` to use.

### Attributes

#### layout *: [F2QLayout](qiskit_fermions.transpiler.F2QLayout.html.md#qiskit_fermions.transpiler.F2QLayout)*

The user-provided mapping of [`FermionicRegister`](qiskit_fermions.circuit.FermionicRegister.html.md#qiskit_fermions.circuit.FermionicRegister) to
[`QuantumRegister`](https://quantum.cloud.ibm.com/docs/api/qiskit/circuit#qiskit.circuit.QuantumRegister).

### Methods

#### run(dag)

Runs this analysis pass.

* **Parameters:**
  **dag** ([*DAGCircuit*](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.dagcircuit.DAGCircuit)) – the DAG circuit representation of a [`FermionicCircuit`](qiskit_fermions.circuit.FermionicCircuit.html.md#qiskit_fermions.circuit.FermionicCircuit).
* **Returns:**
  The unchanged input. But the `property_set` of this transpilation pipeline will
  be updated.
* **Return type:**
  [*DAGCircuit*](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.dagcircuit.DAGCircuit)

### Inherited Methods

#### execute(passmanager_ir, state, callback=None)

Execute optimization task for input Qiskit IR.

* **Parameters:**
  * **passmanager_ir** (*IR*) – Qiskit IR to optimize.
  * **state** ([*PassManagerState*](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.passmanager.PassManagerState)) – State associated with workflow execution by the pass manager itself.
  * **callback** ([*Callable*](https://docs.python.org/3/library/collections.abc.html#collections.abc.Callable) *[* *[*[*Task*](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.passmanager.Task) *,* *IR_OUT* *,* [*PropertySet*](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.passmanager.PropertySet) *,* [*float*](https://docs.python.org/3/builtins/functions.html#float) *,* [*int*](https://docs.python.org/3/builtins/functions.html#int) *]* *,* *None* *]*  *|* *None*) – A callback function which is called per execution of optimization task.
* **Returns:**
  Optimized Qiskit IR and state of the workflow.
* **Return type:**
  [tuple](https://docs.python.org/3/builtins/stdtypes.html#tuple)[*IR_OUT*, [*PassManagerState*](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.passmanager.PassManagerState)]

#### name()

Name of the pass.

* **Return type:**
  [str](https://docs.python.org/3/builtins/stdtypes.html#str)

#### update_status(state, run_state)

Update workflow status.

* **Parameters:**
  * **state** ([*PassManagerState*](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.passmanager.PassManagerState)) – Pass manager state to update.
  * **run_state** (*RunState*) – Completion status of current task.
* **Returns:**
  Updated pass manager state.
* **Return type:**
  [*PassManagerState*](https://quantum.cloud.ibm.com/docs/api/qiskit/qiskit.passmanager.PassManagerState)