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qiskit.opflow.gradients.CircuitQFI GitHub(opens in a new tab)

Bases: ConverterBase

Deprecated: 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

Deprecated since version 0.24.0

The class qiskit.opflow.gradients.circuit_qfis.circuit_qfi.CircuitQFI is deprecated as of qiskit-terra 0.24.0. It will be removed in the Qiskit 1.0 release. For code migration guidelines, visit in a new tab).



abstract convert(operator, params)



An operator whose evaluation yields the QFI metric tensor.


ValueError(opens in a new tab) – If params contains a parameter not present in operator.

Return type


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