qiskit.aqua.operators.gradients.CircuitQFI
class CircuitQFI
Circuit to Quantum Fisher Information operator converter.
Converter for changing parameterized circuits into operators whose evaluation yields Quantum Fisher Information metric tensor with respect to the given circuit parameters
This is distinct from DerivativeBase converters which take gradients of composite operators and handle things like differentiating combo_fn’s and enforcing product rules when operator coefficients are parameterized.
CircuitQFI - uses quantum techniques to get the QFI of circuits DerivativeBase - uses classical techniques to differentiate opflow data structures
__init__
__init__()
Initialize self. See help(type(self)) for accurate signature.
Methods
convert
abstract convert(operator, params=None)
Parameters
- operator (
OperatorBase) – The operator corresponding to the quantum state for which we compute the QFI. - params (
Union[ParameterVector,ParameterExpression,List[ParameterExpression],None]) – The parameters with respect to which we are computing the QFI.
Return type
OperatorBase
Returns
An operator whose evaluation yields the QFI metric tensor.
Raises
ValueError – If params contains a parameter not present in operator.