Source code for scqubits.ui.qubit_widget

# qubit_widget.py
#
# This file is part of scqubits: a Python package for superconducting qubits,
# Quantum 5, 583 (2021). https://quantum-journal.org/papers/q-2021-11-17-583/
#
#    Copyright (c) 2019 and later, Jens Koch and Peter Groszkowski
#    All rights reserved.
#
#    This source code is licensed under the BSD-style license found in the
#    LICENSE file in the root directory of this source tree.
############################################################################

from typing import Any, Callable, Dict

import scqubits.core.units as units
import scqubits.utils.misc as utils

try:
    import ipywidgets
except ImportError:
    _HAS_IPYWIDGETS = False
else:
    _HAS_IPYWIDGETS = True

try:
    from IPython.display import display
except ImportError:
    _HAS_IPYTHON = False
else:
    _HAS_IPYTHON = True


@utils.Required(ipywidgets=_HAS_IPYWIDGETS, IPython=_HAS_IPYTHON)
def create_widget(
    callback_func: Callable, init_params: Dict[str, Any], image_filename: str = None
) -> None:
    """
    Displays ipywidgets for initialization of a QuantumSystem object.

    Parameters
    ----------
    callback_func:
        callback_function depends on all the parameters provided as keys (str) in the
        parameter_dict, and is called upon changes of values inside the widgets
    init_params:
        names and values of initialization parameters
    image_filename:
        file name for circuit image to be displayed alongside the qubit
    """
    widgets = {}
    box_list = []
    for name, value in init_params.items():
        label_str = name
        # NOTE: This will break if names of energy parameters in future qubits do not start with 'E'
        if name[0] == "E":
            label_str += " [" + units.get_units() + "]"
        elif name == "flux":
            label_str += r" [$\Phi_0$]"
        label = ipywidgets.Label(value=label_str)
        if isinstance(value, float):
            enter_widget = ipywidgets.FloatText
        else:
            enter_widget = ipywidgets.IntText

        widgets[name] = enter_widget(
            value=value,
            description="",
            disabled=False,
            layout=ipywidgets.Layout(width="150px"),
        )
        box_list.append(
            ipywidgets.HBox(
                [label, widgets[name]],
                layout=ipywidgets.Layout(justify_content="flex-end"),
            )
        )

    if image_filename:
        file = open(image_filename, "rb")
        image = file.read()
        image_widget = ipywidgets.Image(
            value=image, format="jpg", layout=ipywidgets.Layout(width="700px")
        )
        ui_widget = ipywidgets.HBox(
            [ipywidgets.VBox(box_list), ipywidgets.VBox([image_widget])]
        )
    else:
        ui_widget = ipywidgets.VBox(box_list)

    out = ipywidgets.interactive_output(callback_func, widgets)
    display(ui_widget, out)