Source code for qiskit_aer.noise.device.parameters

# This code is part of Qiskit.
#
# (C) Copyright IBM 2018, 2019.
#
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
#
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.

"""
Functions to extract device error parameters from backend properties.
"""

from numpy import inf

# Time and frequency unit conversions
_NANOSECOND_UNITS = {"s": 1e9, "ms": 1e6, "┬Ás": 1e3, "us": 1e3, "ns": 1}
_GHZ_UNITS = {"Hz": 1e-9, "KHz": 1e-6, "MHz": 1e-3, "GHz": 1, "THz": 1e3}


[docs]def gate_param_values(properties): """ Return parameter error values from a devices BackendProperties. Args: properties (BackendProperties): device backend properties Returns: list: A list of tuples ``(name, qubits, time, error)``. If gate error or gate_length information is not available ``None`` will be returned for value. """ values = [] for gate in properties.gates: name = gate.gate qubits = gate.qubits # Check for gate time information gate_length = None # default value time_param = _check_for_item(gate.parameters, "gate_length") if hasattr(time_param, "value"): gate_length = time_param.value if hasattr(time_param, "unit"): # Convert gate time to ns gate_length *= _NANOSECOND_UNITS.get(time_param.unit, 1) # Check for gate error information gate_error = None # default value error_param = _check_for_item(gate.parameters, "gate_error") if hasattr(error_param, "value"): gate_error = error_param.value values.append((name, qubits, gate_length, gate_error)) return values
[docs]def gate_error_values(properties): """ Return gate error values from a devices BackendProperties. Args: properties (BackendProperties): device backend properties Returns: list: A list of tuples ``(name, qubits, value)``. If gate error information is not available ``None`` will be returned for value. """ values = [] for gate in properties.gates: name = gate.gate qubits = gate.qubits value = None # default value params = _check_for_item(gate.parameters, "gate_error") if hasattr(params, "value"): value = params.value values.append((name, qubits, value)) return values
[docs]def gate_length_values(properties): """ Return gate length values from a devices BackendProperties. Args: properties (BackendProperties): device backend properties Returns: list: A list of tuples ``(name, qubits, value)``. If gate length information is not available ``None`` will be returned for value. Additional Information: Gate length values are returned in nanosecond (ns) units. """ values = [] for gate in properties.gates: name = gate.gate qubits = gate.qubits value = None # default value params = _check_for_item(gate.parameters, "gate_length") if hasattr(params, "value"): value = params.value if hasattr(params, "unit"): # Convert gate time to ns value *= _NANOSECOND_UNITS.get(params.unit, 1) values.append((name, qubits, value)) return values
[docs]def readout_error_values(properties): """ Return readout error values from a devices BackendProperties. Args: properties (BackendProperties): device backend properties Returns: list: A list of readout error values for qubits. If readout error information is not available None will be returned for value. """ values = [] for qubit_props in properties.qubits: value = None # default value params_roerror = _check_for_item(qubit_props, "readout_error") params_m1p0 = _check_for_item(qubit_props, "prob_meas1_prep0") params_m0p1 = _check_for_item(qubit_props, "prob_meas0_prep1") if hasattr(params_m1p0, "value") and hasattr(params_m0p1, "value"): value = [params_m1p0.value, params_m0p1.value] elif hasattr(params_roerror, "value"): value = [params_roerror.value, params_roerror.value] values.append(value) return values
[docs]def thermal_relaxation_values(properties): """ Return T1, T2 and frequency values from a devices BackendProperties. Args: properties (BackendProperties): device backend properties Returns: list: A list of tuples ``(T1, T2, freq)`` for each qubit in the device. If :math:`T_1`, :math:`T_2`, or frequency cannot be found for qubit a value of ``Numpy.inf`` will be used. Additional Information: :math:`T_1` and :math:`T_2` values are returned in nanosecond (ns) units and frequency is returned in gigahertz (GHz) units if ``unit`` for each ``value`` is provided in ``properties``. Otherwise, the raw values (in unknown original units) are returned. """ values = [] for qubit_props in properties.qubits: # pylint: disable=invalid-name # Default values t1, t2, freq = inf, inf, inf # Get the readout error value t1_params = _check_for_item(qubit_props, "T1") t2_params = _check_for_item(qubit_props, "T2") freq_params = _check_for_item(qubit_props, "frequency") # Load values from parameters if hasattr(t1_params, "value"): t1 = t1_params.value if hasattr(t1_params, "unit"): # Convert to nanoseconds t1 *= _NANOSECOND_UNITS.get(t1_params.unit, 1) if hasattr(t2_params, "value"): t2 = t2_params.value if hasattr(t2_params, "unit"): # Convert to nanoseconds t2 *= _NANOSECOND_UNITS.get(t2_params.unit, 1) if hasattr(freq_params, "value"): freq = freq_params.value if hasattr(freq_params, "unit"): # Convert to Gigahertz freq *= _GHZ_UNITS.get(freq_params.unit, 1) values.append((t1, t2, freq)) return values
def _check_for_item(lst, name): """Search list for item with given name.""" filtered = [item for item in lst if item.name == name] if not filtered: return None else: return filtered[0]