RemoveIdentityEquivalent

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

Bases: TransformationPass

Remove gates with negligible effects.

Removes gates whose effect is close to an identity operation, up to the specified tolerance. Zero qubit gates such as GlobalPhaseGate are not considered by this pass.

For a cutoff fidelity $f$ , this pass removes gates whose average gate fidelity with respect to the identity is below $f$ . Concretely, a gate $G$ is removed if $\bar F < f$ where

\bar{F} = \frac{1 + F_{\text{process}}}{1 + d},\ F_{\text{process}} = \frac{|\mathrm{Tr}(G)|^2}{d^2}

where $d = 2^n$ is the dimension of the gate for $n$ qubits.

Initialize the transpiler pass.

Parameters

approximation_degree – The degree to approximate for the equivalence check. This can be a floating point value between 0 and 1, or None. If the value is 1 this does not approximate above floating point precision. For a value < 1 this is used as a scaling factor for the cutoff fidelity. If the value is None this approximates up to the fidelity for the gate specified in target.
target – If approximation_degree is set to None and a Target is provided for this field the tolerance for determining whether an operation is equivalent to identity will be set to the reported error rate in the target. If approximation_degree (the default) this has no effect, if approximation_degree=None it uses the error rate specified in the Target for the gate being evaluated, and a numeric value other than 1 with target set is used as a scaling factor of the target’s error rate.

Attributes

is_analysis_pass

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.

is_transformation_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).

Methods

execute

execute(passmanager_ir, state, callback=None)

GitHub

Execute optimization task for input Qiskit IR.

Parameters

passmanager_ir (Any) – Qiskit IR to optimize.
state (PassManagerState) – State associated with workflow execution by the pass manager itself.
callback (Callable | None) – A callback function which is caller per execution of optimization task.