qiskit.opflow module is deprecated and will be removed no earlier than 3 months after the release date. For code migration guidelines, visit https://qisk.it/opflow_migration (opens in a new tab).
Converters are objects which manipulate Operators, usually traversing an Operator to change certain sub-Operators into a desired representation. Often the converted Operator is isomorphic or approximate to the original Operator in some way, but not always. For example, a converter may accept
CircuitOp and return a
PauliOp’s representing the circuit unitary. Converters may not have polynomial space or time scaling in their operations. On the contrary, many converters, such as a
MatrixEvolution, which convert
MatrixOp’s internally, will require time or space exponential in the number of qubits unless a clever trick is known (such as the use of sparse matrices).
The converter base class simply enforces the presence of a
|Deprecated: Converters take an Operator and return a new Operator, generally isomorphic in some way with the first, but with certain desired properties.|
In addition to the base class, directory holds a few miscellaneous converters which are used frequently around the Operator flow.
|Deprecated: The CircuitSampler traverses an Operator and converts any CircuitStateFns into approximations of the state function by a DictStateFn or VectorStateFn using a quantum backend.|
|Deprecated: The AbelianGrouper converts SummedOps into a sum of Abelian sums.|
|Deprecated: Converts |
|Deprecated: Converter for changing Paulis into other bases.|
|Deprecated: Two qubit reduction converter which eliminates the central and last qubit in a list of Pauli that has diagonal operators (Z,I) at those positions.|