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

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Bases: TransformationPass

Replace each block of consecutive gates by a single Unitary node.

Pass to consolidate sequences of uninterrupted gates acting on the same qubits into a Unitary node, to be resynthesized later, to a potentially more optimal subcircuit.


This pass assumes that the ‘blocks_list’ property that it reads is given such that blocks are in topological order. The blocks are collected by a previous pass, such as Collect2qBlocks.

ConsolidateBlocks initializer.

If kak_basis_gate is not None it will be used as the basis gate for KAK decomposition. Otherwise, if basis_gates is not None a basis gate will be chosen from this list. Otherwise, the basis gate will be CXGate.


  • kak_basis_gate (Gate) – Basis gate for KAK decomposition.
  • force_consolidate (bool(opens in a new tab)) – Force block consolidation.
  • basis_gates (List(str(opens in a new tab))) – Basis gates from which to choose a KAK gate.
  • approximation_degree (float(opens in a new tab)) – a float between [0.0,1.0][0.0, 1.0]. Lower approximates more.
  • target (Target) – The target object for the compilation target backend.



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.


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).



execute(passmanager_ir, state, callback=None)

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Execute optimization task for input Qiskit IR.



Optimized Qiskit IR and state of the workflow.

Return type

tuple(opens in a new tab)[Any(opens in a new tab), qiskit.passmanager.compilation_status.PassManagerState]



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Name of the pass.

Return type

str(opens in a new tab)



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Run the ConsolidateBlocks pass on dag.

Iterate over each block and replace it with an equivalent Unitary on the same wires.


update_status(state, run_state)

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Update workflow status.


  • state (PassManagerState) – Pass manager state to update.
  • run_state (RunState) – Completion status of current task.


Updated pass manager state.

Return type


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