See also

This notebook can be downloaded here

Serialization

Quantify allows for serialization of :class:~quantify_scheduler.QuantumDevice, :class:~quantify_scheduler.DeviceElement (e.g. :class:~quantify_scheduler.BasicTransmonElement) and :class:~quantify_scheduler.Schedule objects to json strings and json files. Each class has the following methods:

• to_json : Converts the object into a json string.

• from_json : Converts a json string back into the object.

• to_json_file : Stores the json string to a file.

• from_json_file : Reads the json string from a file and converts it back into the object.

Examples

(De)Serializing a QuantumDevice object to json string

from quantify_scheduler import BasicTransmonElement, QuantumDevice
import json

QuantumDevice.close_all()
device = QuantumDevice("single_qubit_device")
q0 = BasicTransmonElement("q0")
device.cfg_sched_repetitions(512)
device.add_element(q0)
...

device_json = device.to_json()
print(json.dumps(json.loads(device_json), indent=4))

{
    "deserialization_type": "quantify_scheduler.device_under_test.quantum_device.QuantumDevice",
    "data": {
        "name": "single_qubit_device",
        "elements": {
            "q0": {
                "deserialization_type": "quantify_scheduler.device_under_test.transmon_element.BasicTransmonElement",
                "mode": "__init__",
                "data": {
                    "name": "q0",
                    "reset": {
                        "duration": 0.0002
                    },
                    "rxy": {
                        "amp180": NaN,
                        "motzoi": 0,
                        "duration": 2e-08
                    },
                    "measure": {
                        "pulse_type": "SquarePulse",
                        "pulse_amp": 0.25,
                        "pulse_duration": 3e-07,
                        "acq_channel": 0,
                        "acq_delay": 0,
                        "integration_time": 1e-06,
                        "reset_clock_phase": true,
                        "acq_weights_a": {
                            "deserialization_type": "ndarray",
                            "mode": "__init__",
                            "data": []
                        },
                        "acq_weights_b": {
                            "deserialization_type": "ndarray",
                            "mode": "__init__",
                            "data": []
                        },
                        "acq_weights_sampling_rate": 1000000000.0,
                        "acq_weight_type": "SSB",
                        "acq_rotation": 0,
                        "acq_threshold": 0,
                        "num_points": 1
                    },
                    "pulse_compensation": {
                        "max_compensation_amp": NaN,
                        "time_grid": NaN,
                        "sampling_rate": NaN
                    },
                    "ports": {
                        "microwave": "q0:mw",
                        "flux": "q0:fl",
                        "readout": "q0:res"
                    },
                    "clock_freqs": {
                        "f01": NaN,
                        "f12": NaN,
                        "readout": NaN
                    }
                }
            }
        },
        "edges": {},
        "cfg_sched_repetitions": 512
    }
}

Loading the object from the json string is done using the from_json method:

deserialized_device = QuantumDevice.from_json(device_json)

(De)Serializing a QuantumDevice object to json file

You can optionally specify the path as an argument to the to_json_file method.

device.to_json_file("/tmp")

'/tmp/single_qubit_device_2025-06-21_02-12-38_UTC.json'

or save it automatically to the current data directory using the objects name:

from quantify_core.data.handling import set_datadir
set_datadir("/tmp")
device.to_json_file() # Saves to "/tmp/single_qubit_device_2024-11-14_13-36-59_UTC.json"

'/tmp/single_qubit_device_2025-06-21_02-12-38_UTC.json'

and the timestamp can be omitted by setting add_timestamp=False:

device.to_json_file(add_timestamp=False) # Saves to "/tmp/single_qubit_device.json"

'/tmp/single_qubit_device.json'

loading the object from the json file is done using the from_json_file method:

deserialized_device = QuantumDevice.from_json_file("/tmp/single_qubit_device.json")