Result of a quantum program
After the Job is executed, a result is returned from the QPU. It will be
encapsulated in a Result object. Depending on the type of the job, the result
will either be composed of several samples, or a scalar in case that an observable is measured.
A Result object mainly contains the following information:
raw_data : a list of
Sample(for a sampling job)value : a scalar output (for an observable job)
value_data : the value of individual terms (for an observable job)
meta_data : any additional information from the QPU
statevector : the entire state vector (only available if the simulator offers this feature)
For a sampling job, the result is returned as a list of samples, and the structure of a sample is described below:
state : the measured state
amplitude : the amplitude of the measured state
probability : the probability of the obtained state
intermediate_measurements : a list summarizing the results of intermediate measurements
err : the approximated error of the sampling
Additional information can be returned from a QPU (or a plugin when post processing) in the meta_data, for example:
the simulation time
the number of circuits of the final job in case of an observable measurement job
the optimal parameters and the optimization trace in case of a variational optimization job
Please refer to the API reference of the specific QPUs and plugins for detailed metadata that will be added.
The result returned from a QPU can be modified by the plugins in the execution stack, through the post_process method. This feature allows the plugins to return the result to the user in a desirable format.