# cirq.DensityMatrixTrialResult¶

class cirq.DensityMatrixTrialResult(params: cirq.study.resolver.ParamResolver, measurements: Dict[str, numpy.ndarray], final_simulator_state: cirq.sim.density_matrix_simulator.DensityMatrixSimulatorState)[source]

A SimulationTrialResult for DensityMatrixSimulator runs.

The density matrix that is stored in this result is returned in the
computational basis with these basis states defined by the qubit_map.
In particular the value in the qubit_map is the index of the qubit,
and these are translated into binary vectors where the last qubit is
the 1s bit of the index, the second-to-last is the 2s bit of the index,
and so forth (i.e. big endian ordering). The density matrix is a
2 ** num_qubits square matrix, with rows and columns ordered by
the computational basis as just described.

Example

qubit_map: {QubitA: 0, QubitB: 1, QubitC: 2}
Then the returned density matrix will have (row and column) indices
mapped to qubit basis states like the following table

QubitA

QubitB

QubitC

0

0

0

0

1

0

0

1

2

0

1

0

3

0

1

1

4

1

0

0

5

1

0

1

6

1

1

0

7

1

1

1

params

A ParamResolver of settings used for this result.

measurements
A dictionary from measurement gate key to measurement
results. Measurement results are a numpy ndarray of actual boolean
measurement results (ordered by the qubits acted on by the
measurement gate.)
final\_simulator\_state
The final simulator state of the system after the
trial finishes.
final\_density\_matrix

The final density matrix of the system.

__init__(params: cirq.study.resolver.ParamResolver, measurements: Dict[str, numpy.ndarray], final_simulator_state: cirq.sim.density_matrix_simulator.DensityMatrixSimulatorState) → None[source]

Initialize self. See help(type(self)) for accurate signature.

Attributes

 qubit_map A map from Qid to index used to define the ordering of the basis in