Transpiler Passes (qiskit.transpiler.passes)

Layout Selection (Placement)

SetLayout(*args, **kwargs)	Set the layout property to the given layout.
TrivialLayout(*args, **kwargs)	Choose a Layout by assigning n circuit qubits to device qubits 0, .., n-1.
DenseLayout(*args, **kwargs)	Choose a Layout by finding the most connected subset of qubits.
NoiseAdaptiveLayout(*args, **kwargs)	Choose a noise-adaptive Layout based on current calibration data for the backend.
CSPLayout(*args, **kwargs)	If possible, chooses a Layout as a CSP, using backtracking.
ApplyLayout(*args, **kwargs)	Transform a circuit with virtual qubits into a circuit with physical qubits.
Layout2qDistance(*args, **kwargs)	Evaluate how good the layout selection was.
EnlargeWithAncilla(*args, **kwargs)	Extend the dag with virtual qubits that are in layout but not in the circuit yet.
FullAncillaAllocation(*args, **kwargs)	Allocate all idle nodes from the coupling map as ancilla on the layout.

Routing

BasicSwap(*args, **kwargs)	Map (with minimum effort) a DAGCircuit onto a coupling_map adding swap gates.
LookaheadSwap(*args, **kwargs)	Map input circuit onto a backend topology via insertion of SWAPs.
StochasticSwap(*args, **kwargs)	Map a DAGCircuit onto a coupling_map adding swap gates.

Basis Change

Unroller(*args, **kwargs)	Unroll a circuit to a given basis.
Unroll3qOrMore(*args, **kwargs)	Recursively expands 3q+ gates until the circuit only contains 2q or 1q gates.
Decompose([gate])	Expand a gate in a circuit using its decomposition rules.

Optimizations

Optimize1qGates(*args, **kwargs)	Optimize chains of single-qubit u1, u2, u3 gates by combining them into a single gate.
Collect2qBlocks(*args, **kwargs)	Collect sequences of uninterrupted gates acting on 2 qubits.
ConsolidateBlocks(*args, **kwargs)	Replace each block of consecutive gates by a single Unitary node.
CXCancellation(*args, **kwargs)	Cancel back-to-back cx gates in dag.
CommutationAnalysis(*args, **kwargs)	Analysis pass to find commutation relations between DAG nodes.
CommutativeCancellation(*args, **kwargs)	Cancel the redundant (self-adjoint) gates through commutation relations.
RemoveDiagonalGatesBeforeMeasure(*args, **kwargs)	Remove diagonal gates (including diagonal 2Q gates) before a measurement.
RemoveResetInZeroState(*args, **kwargs)	Remove reset gate when the qubit is in zero state.
CrosstalkAdaptiveSchedule(*args, **kwargs)	Crosstalk mitigation through adaptive instruction scheduling.

Circuit Analysis

Width(*args, **kwargs)	Calculate the width of a DAG circuit.
Depth(*args, **kwargs)	Calculate the depth of a DAG circuit.
Size(*args, **kwargs)	Calculate the size of a DAG circuit.
CountOps(*args, **kwargs)	Count the operations in a DAG circuit.
CountOpsLongestPath(*args, **kwargs)	Count the operations on the longest path in a DAGcircuit.
NumTensorFactors(*args, **kwargs)	Calculate the number of tensor factors of a DAG circuit.
DAGLongestPath(*args, **kwargs)	Return the longest path in a DAGcircuit as a list of DAGNodes.

Additional Passes

CheckMap(*args, **kwargs)	Check if a DAG circuit is already mapped to a coupling map.
CheckCXDirection(*args, **kwargs)	Check if the CNOTs follow the right direction with respect to the coupling map.
CXDirection(*args, **kwargs)	Rearrange the direction of the cx nodes to match the directed coupling map.
MergeAdjacentBarriers(*args, **kwargs)	Return a circuit with any adjacent barriers merged together.
BarrierBeforeFinalMeasurements(*args, **kwargs)	Add a barrier before final measurements.
RemoveFinalMeasurements(*args, **kwargs)	Remove final measurements and barriers at the end of a circuit.
DAGFixedPoint(*args, **kwargs)	Check if the DAG has reached a fixed point.
FixedPoint(*args, **kwargs)	Check if a property reached a fixed point.