mjolnir.helpers

This module defines some helper functions.

Functions

calculate_ramp_time_with_filter(slew_rate, ...)	Calculate the time for a linear ramp with an analogue RC filter to settle at thresh.
calculate_rise_time(RC[, thresh])	Computes the rise time of a single-stage RC filter.
camel_to_snake(name)	Convert a CamelCase name to snake_case.
find_param_source(param)	Return the root source of a parameter.
find_parameters(instrument, *params_to_exclude)	Recursively find all parameters on instrument except params_to_exclude, those of class param_classes_to_exclude, or those whose physical instrument is in underlying_instruments_to_exclude, up to a nesting level of max_nesting_level.
find_parameters_with_nesting_level_below(...)	Find all parameters in instrument and submodules at most nesting_level deep.
load_station(filename[, use_monitor, ...])	Load the station specified in filename, which should be a file living in mjolnir/config.
make_dc_constant_V_blocking(channel[, thresh])	Modify the dc_constant_V parameter of a QDAC-II channel to block until the voltage has settled at thresh of its designated value.
make_dc_constant_V_nonblocking(channel)	Revert make_dc_constant_V_blocking().
mean_and_standard_error(data[, axis, alpha])	Compute the mean and standard error on the mean.
rise_time_dependent_post_delay(self, _, val, ...)	Side effect for bob_filter_RC parameter of QDAC-II channels.
save_to_hdf5(run_id, savepath, *params_to_skip)	Extract run_id from the database and save to hdf5.
setup_logging(levels)	Set up logging (only for calibration module currently).
start_monitor(station, *params_to_exclude[, ...])	Start a monitor on parameters of instruments on station.
timed(func)	Adds timing to func and reports it to stdout.
update_qdac2_line_label(channel, gate_type, side)	Give QDAC2 channels more meaningful labels.

mjolnir.helpers.calculate_ramp_time_with_filter(slew_rate, voltage_swing, RC, thresh)

Calculate the time for a linear ramp with an analogue RC filter to settle at thresh.

The settling time can be obtained by inverse Laplace-transform of the transfer function

\[C(s) = \frac{1}{s\tau + 1}\times\frac{k}{s^2}\]

where \(\tau=RC\) and \(k\) is the slope of the ramp.

Parameters:

• slew_rate (float) – Slope of the ramp.

• voltage_swing (float) – Range of the ramp.

• RC (float) – Time constant of the filter.

• thresh (float) – Settling threshold that should be achieved.

Return type:

float

mjolnir.helpers.calculate_rise_time(RC, thresh=0.9)

Computes the rise time of a single-stage RC filter.

Parameters:

RC (float)

Return type:

float

mjolnir.helpers.camel_to_snake(name)

Convert a CamelCase name to snake_case.

Parameters:

name (str)

Return type:

str

mjolnir.helpers.find_param_source(param)

Return the root source of a parameter.

Parameters:

param (ParameterBase)

Return type:

ParameterBase

mjolnir.helpers.find_parameters(instrument, *params_to_exclude, instruments_to_exclude=(), underlying_instruments_to_exclude=(), param_classes_to_exclude=(), only_gettable=False, max_nesting_level=0)

Recursively find all parameters on instrument except params_to_exclude, those of class param_classes_to_exclude, or those whose physical instrument is in underlying_instruments_to_exclude, up to a nesting level of max_nesting_level.

Parameters:

• instrument (MetadatableWithName)

• params_to_exclude (Parameter)

• instruments_to_exclude (Sequence[InstrumentBase])

• underlying_instruments_to_exclude (Sequence[InstrumentBase])

• param_classes_to_exclude (tuple[type[Parameter], ...] | type[Parameter])

• only_gettable (bool)

• max_nesting_level (int)

Return type:

Iterator[Parameter]

mjolnir.helpers.find_parameters_with_nesting_level_below(instrument, nesting_level)

Find all parameters in instrument and submodules at most nesting_level deep.

Parameters:

• instrument (InstrumentBase)

• nesting_level (int)

Return type:

Iterator[Parameter]

mjolnir.helpers.load_station(filename, use_monitor=False, update_snapshot=False)

Load the station specified in filename, which should be a file living in mjolnir/config.

Parameters:

• filename (str | Sequence[str])

• use_monitor (bool)

• update_snapshot (bool)

Return type:

Station

mjolnir.helpers.make_dc_constant_V_blocking(channel, thresh=0.99)

Modify the dc_constant_V parameter of a QDAC-II channel to block until the voltage has settled at thresh of its designated value.

Parameters:

• channel (QDac2Channel)

• thresh (float)

mjolnir.helpers.make_dc_constant_V_nonblocking(channel)

Revert make_dc_constant_V_blocking().

Parameters:

channel (QDac2Channel)

mjolnir.helpers.mean_and_standard_error(data, axis=0, alpha=0.05)

Compute the mean and standard error on the mean.

References

https://en.wikipedia.org/wiki/Student%27s_t-distribution#Confidence_intervals

Parameters:

• data (numpy.typing.ArrayLike)

• axis (int)

• alpha (float)

Return type:

tuple[float, float]

mjolnir.helpers.rise_time_dependent_post_delay(self, _, val, channel, thresh)

Side effect for bob_filter_RC parameter of QDAC-II channels.

Waits at least as long as a step impulse takes to settle at thresh.

Use together with py:functools.partial().

Todo

Unused as of now.

Parameters:

• _ (float)

• val (float)

• channel (QDac2Channel)

• thresh (float)

Return type:

None

mjolnir.helpers.save_to_hdf5(run_id, savepath, *params_to_skip, method='dataset', compress=False)

Extract run_id from the database and save to hdf5.

Parameters:

• run_id (int) – Captured run id.

• savepath (PathLike) – File where the dataset should be saved.

• *params_to_skip – Names of dataset parameters to skip exporting.

• method (Literal['dataset', 'dataarray']) – Export to an xarray Dataset or DataArray.

• compress (bool) – Use level 5 gzip compression.

mjolnir.helpers.setup_logging(levels)

Set up logging (only for calibration module currently).

Since qcodes controls the root logger, we need to make sure loggers are independent of it.

Parameters:

levels (dict[str, int])

mjolnir.helpers.start_monitor(station, *params_to_exclude, instruments_to_exclude=(), underlying_instruments_to_exclude=(), param_classes_to_exclude=(), max_nesting_level=0, update=False, url='localhost', port=3000, show=False, **monitor_kwargs)

Start a monitor on parameters of instruments on station.

Parameters:

• station (Station) – The qcodes station hosting the instruments.

• *params_to_exclude (ParameterBase) – Parameters to exclude from the monitor.

• underlying_instruments_to_exclude (Sequence[InstrumentBase]) – Exclude parameters bound to these underlying instruments.

• instruments_to_exclude (Sequence[InstrumentBase]) – Exclude parameters bound to these instruments.

• param_classes_to_exclude (tuple[type[Parameter], ...] | type[Parameter]) – Exclude parameters of these types.

• max_nesting_level (int) – Include parameters of up to this many children.

• update (bool) – Update parameter values.

• url (str) – The url of the server.

• port (int) – The port under which to reach the server.

• show (bool) – Open a new webbrowser tab with the monitor.

• **monitor_kwargs – Keyword arguments passed to the Monitor constructor.

Returns:

• server – The web server running the monitor.

• monitor – The Monitor instance.

Return type:

tuple[ThreadedWebserver, Monitor]

mjolnir.helpers.timed(func)

Adds timing to func and reports it to stdout.

Parameters:

func (Callable[[~_P], _T])

Return type:

Callable[[~_P], _T]

mjolnir.helpers.update_qdac2_line_label(channel, gate_type, side)

Give QDAC2 channels more meaningful labels.