Choose a noise-adaptive Layout based on current calibration data for the backend.
This pass associates a physical qubit (int) to each virtual qubit of the circuit (Qubit), using calibration data.
The pass implements the qubit mapping method from: Noise-Adaptive Compiler Mappings for Noisy Intermediate-Scale Quantum Computers Prakash Murali, Jonathan M. Baker, Ali Javadi-Abhari, Frederic T. Chong, Margaret R. Martonosi ASPLOS 2019 (arXiv:1901.11054).
Ordering of edges
Map qubits edge-by-edge in the order of decreasing frequency of occurrence in the program dag.
If an edge exists with both endpoints unmapped,
pick the best available hardware cx to execute this edge.
When an edge exists with one endpoint unmapped,
map that endpoint to a location which allows
maximum reliability for CNOTs with previously mapped qubits.
In the end if there are unmapped qubits (which don't
participate in any CNOT), map them to any available
even though a layout is not strictly a property of the DAG, in the transpiler architecture it is best passed around between passes by being set in property_set.
backend_prop (BackendProperties) – backend properties object
TranspilerError – if invalid options
Return the name of the pass.
Run the NoiseAdaptiveLayout pass on dag.
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).