qml.devices.qubit_mixed.simulate¶
- simulate(circuit, debugger=None, state_cache=None, **execution_kwargs)[source]¶
Simulate the execution of a single quantum script.
This internal function is used by the
default.mixeddevice to simulate quantum circuits and return the results of specified measurements. It supports both analytic and finite-shot simulations and can handle advanced features such as readout errors and batched states.- Parameters
circuit (QuantumScript) – The quantum script containing the operations and measurements to be simulated.
debugger (_Debugger) – An optional debugger instance used to track and debug circuit execution.
state_cache (dict) – An optional cache to store the final state of the circuit, keyed by the circuit hash.
- Keyword Arguments
rng (Optional[Union[None, int, array_like[int], SeedSequence, BitGenerator, Generator]]) – A seed-like parameter for
numpy.random.default_rng. If no value is provided, a default random number generator is used.prng_key (Optional[jax.random.PRNGKey]) – A key for the JAX pseudo-random number generator. If None, a random key is generated. Only relevant for JAX-based simulations.
interface (str) – The machine learning interface used to create the initial state.
readout_errors (List[Callable]) – A list of quantum channels (callable functions) applied to each wire during measurement to simulate readout errors.
- Returns
The results of the simulation. Measurement results are returned as a tuple, with each entry corresponding to a specified measurement in the circuit.
- Return type
tuple(TensorLike)
Notes
This function assumes that all operations in the circuit provide matrices.
Non-commuting observables can be measured simultaneously, with the results returned in the same tuple.
Example
Simulate a quantum circuit with both expectation values and probability measurements:
from pennylane.devices.qubit_mixed import simulate from pennylane.tape import QuantumScript # Define a quantum script circuit = QuantumScript( ops=[qml.RX(1.2, wires=0)], measurements=[expval(qml.PauliX(0)), qml.probs(wires=(0, 1))] )
>>> print(simulate(circuit)) (0.0, array([0.68117888, 0.0, 0.31882112, 0.0]))
Usage Details
Analytic simulations (without shots) compute exact expectation values and probabilities.
Finite-shot simulations sample from the distribution defined by the quantum state, using the specified RNG or PRNG key. Readout errors, if provided, are applied during the measurement step.
The state_cache parameter can be used to cache the final state for reuse in subsequent calculations.
See also
get_final_state(),measure_final_state()