qiskit.transpiler.passes.GateDirection

class GateDirection(*args, **kwargs)

Modify asymmetric gates to match the hardware coupling direction.

This pass makes use of the following identities:

                     ┌───┐┌───┐┌───┐
q_0: ──■──      q_0: ┤ H ├┤ X ├┤ H ├
     ┌─┴─┐  =        ├───┤└─┬─┘├───┤
q_1: ┤ X ├      q_1: ┤ H ├──■──┤ H ├
     └───┘           └───┘     └───┘

     ┌──────┐          ┌───────────┐┌──────┐┌───┐
q_0: ┤0     ├     q_0: ┤ RY(-pi/2) ├┤1     ├┤ H ├
     │  ECR │  =       └┬──────────┤│  ECR │├───┤
q_1: ┤1     ├     q_1: ─┤ RY(pi/2) ├┤0     ├┤ H ├
     └──────┘           └──────────┘└──────┘└───┘

GateDirection pass.

Parameters

coupling_map (CouplingMap) – Directed graph represented a coupling map.

__init__(coupling_map)

GateDirection pass.

Parameters

coupling_map (CouplingMap) – Directed graph represented a coupling map.

Methods

__init__(coupling_map)	GateDirection pass.
name()	Return the name of the pass.
run(dag)	Run the GateDirection pass on dag.

Attributes

is_analysis_pass	Check if the pass is an analysis pass.
is_transformation_pass	Check if the pass is a transformation pass.

property 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.

property 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).

name()

Return the name of the pass.

run(dag)

Run the GateDirection pass on dag.

Flips the cx nodes to match the directed coupling map. Modifies the input dag.

Parameters

dag (DAGCircuit) – DAG to map.

Returns

The rearranged dag for the coupling map

Return type

DAGCircuit

Raises

TranspilerError – If the circuit cannot be mapped just by flipping the cx nodes.