qiskit.algorithms.PVQD.get_loss¶
- PVQD.get_loss(hamiltonian, ansatz, dt, current_parameters)[source]¶
Get a function to evaluate the infidelity between Trotter step and ansatz.
- Parameters
hamiltonian (BaseOperator | PauliSumOp) – The Hamiltonian under which to evolve.
ansatz (QuantumCircuit) – The parameterized quantum circuit which attempts to approximate the time-evolved state.
dt (float) – The time step.
current_parameters (np.ndarray) – The current parameters.
- Returns
- A callable to evaluate the infidelity and, if gradients are supported and required,
a second callable to evaluate the gradient of the infidelity.
- Return type
tuple[Callable[[np.ndarray], float], Callable[[np.ndarray], np.ndarray]] | None