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# qiskit.transpiler.passes.Optimize1qGates¶

class Optimize1qGates(*args, **kwargs)[source]

Optimize chains of single-qubit u1, u2, u3 gates by combining them into a single gate.

Optimize1qGates initializer.

Parameters
• basis (list[str]) – Basis gates to consider, e.g. [‘u3’, ‘cx’]. For the effects of this pass, the basis is the set intersection between the basis parameter and the set {‘u1’,’u2’,’u3’}.

• eps (float) – EPS to check against

__init__(basis=None, eps=1e-15)[source]

Optimize1qGates initializer.

Parameters
• basis (list[str]) – Basis gates to consider, e.g. [‘u3’, ‘cx’]. For the effects of this pass, the basis is the set intersection between the basis parameter and the set {‘u1’,’u2’,’u3’}.

• eps (float) – EPS to check against

Methods

 __init__([basis, eps]) Optimize1qGates initializer. compose_u3(theta1, phi1, lambda1, theta2, …) Return a triple theta, phi, lambda for the product. Return the name of the pass. run(dag) Run the Optimize1qGates pass on dag. yzy_to_zyz(xi, theta1, theta2[, eps]) Express a Y.Z.Y single qubit gate as a Z.Y.Z gate.

Attributes

 is_analysis_pass Check if the pass is an analysis pass. is_transformation_pass Check if the pass is a transformation pass.
static compose_u3(theta1, phi1, lambda1, theta2, phi2, lambda2)[source]

Return a triple theta, phi, lambda for the product.

u3(theta, phi, lambda)

= u3(theta1, phi1, lambda1).u3(theta2, phi2, lambda2) = Rz(phi1).Ry(theta1).Rz(lambda1+phi2).Ry(theta2).Rz(lambda2) = Rz(phi1).Rz(phi’).Ry(theta’).Rz(lambda’).Rz(lambda2) = u3(theta’, phi1 + phi’, lambda2 + lambda’)

Return theta, phi, lambda.

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)[source]

Run the Optimize1qGates pass on dag.

Parameters

dag (DAGCircuit) – the DAG to be optimized.

Returns

the optimized DAG.

Return type

DAGCircuit

Raises

TranspilerError – if YZY and ZYZ angles do not give same rotation matrix.

static yzy_to_zyz(xi, theta1, theta2, eps=1e-09)[source]

Express a Y.Z.Y single qubit gate as a Z.Y.Z gate.

Solve the equation



Ry(theta1).Rz(xi).Ry(theta2) = Rz(phi).Ry(theta).Rz(lambda)

for theta, phi, and lambda.

Return a solution theta, phi, and lambda.