Utility functions

final_measurement_mapping(circuit)	Return the final measurement mapping for the circuit.
expval(items[, exp_ops])	Compute expectation values from distributions.
stddev(items)	Compute expectation values from distributions.
expval_and_stddev(items[, exp_ops])	Compute expectation values from distributions.
marginal_distribution(dist, indices[, mapping])	Grab the marginal counts from a given distribution.