agentMET4FOF metrologically enabled streams

class agentMET4FOF.metrological_streams.MetrologicalDataStreamMET4FOF(value_unc: Optional[float] = 0.0, time_unc: Optional[float] = 0.0, exp_unc: Optional[float] = None, cov_factor: Optional[float] = 1.0)

Abstract class for creating datastreams with metrological information. Inherits from the DataStreamMET4FOF class

To create a new MetrologicalDataStreamMET4FOF class, inherit this class and call set_metadata() in the constructor. Choose one of two types of datastreams to be created:

• from dataset file (set_data_source()), or
• a waveform generator function (set_generator_function()).

Alternatively, override the next_sample() function if neither option suits the application. For generator functions, sfreq is a required variable to be set on init which sets the sampling frequency and the time-step which occurs when next_sample() is called.

For an example implementation of using generator function, see the built-in MetrologicalSineGenerator class. See tutorials for more implementations.

_generator_function_unc

A generator function for the time and quantity uncertainties which takes in at least one argument time which will be used in next_sample(). The return value must be a 2-tuple of time and value uncertainties each of one of the three types:

• np.ndarray
• pandas DataFrame
• list

Type:Callable

_uncertainty_parameters

Any additional keyword arguments to be supplied to the generator function. Both the calls of the value generator function and of the uncertainty generator function will be supplied with the **_uncertainty_parameters.

Type:Dict

_default_uncertainty_generator(time: Union[List[T], pandas.core.frame.DataFrame, numpy.ndarray], values: Union[List[T], pandas.core.frame.DataFrame, numpy.ndarray]) → Tuple[numpy.ndarray, numpy.ndarray]

Default (standard) uncertainty generator function

Parameters:

• time (Union[List, DataFrame, np.ndarray]) – timestamps
• values (Union[List, DataFrame, np.ndarray]) – values corresponding to timestamps

Returns:

constant time and value uncertainties each of the same shape as time

Return type:

Tuple[np.ndarray, np.ndarray]

_next_sample_generator(batch_size: int = 1) → numpy.ndarray

Internal method for generating a batch of samples from the generator function. Overrides DataStreamMET4FOF._next_sample_generator(). Adds time uncertainty ut and measurement uncertainty uv to sample

set_generator_function(generator_function: Callable = None, uncertainty_generator: Callable = None, sfreq: int = None, **kwargs) → Callable

Set value and uncertainty generators based on user-defined functions. By default, this function resorts to a sine wave generator function and a constant (zero) uncertainty. Initialisation of the generator’s parameters should be done here such as setting the sampling frequency and wave frequency. For setting it with a dataset instead, see set_data_source(). Overwrites the default DataStreamMET4FOF.set_generator_function() method.

Parameters:

• generator_function (callable) – A generator function which takes in at least one argument time which will be used in next_sample().
• uncertainty_generator (callable) – An uncertainty generator function which takes in at least one argument time which will be used in next_sample().
• sfreq (int) – Sampling frequency.
• **kwargs (Optional[Dict[str, Any]]) – Any additional keyword arguments to be supplied to the generator function. The **kwargs will be saved as _uncertainty_parameters. Both the calls of the value generator function and of the uncertainty generator function will be supplied with the **uncertainty_parameters.

Returns:

The uncertainty generator function

Return type:

Callable

time_unc

uncertainties associated with timestamps

Type:Union[float, Iterable[float]]

value_unc

uncertainties associated with the values

Type:Union[float, Iterable[float]]

class agentMET4FOF.metrological_streams.MetrologicalMultiWaveGenerator(sfreq: int = 500, freq_arr: numpy.array = array([50]), ampl_arr: numpy.array = array([1]), phase_ini_arr: numpy.array = array([0]), intercept: float = 0, device_id: str = 'MultiWaveDataGenerator', time_name: str = 'time', time_unit: str = 's', quantity_names: Union[str, Tuple[str, ...]] = ('Length', 'Mass'), quantity_units: Union[str, Tuple[str, ...]] = ('m', 'kg'), misc: Optional[Any] = ' Generator for a linear sum of cosines', value_unc: Union[float, Iterable[float]] = 0.1, time_unc: Union[float, Iterable[float]] = 0, noisy: bool = True)

Class to generate data as a sum of cosine wave and additional Gaussian noise.

Values with associated uncertainty are returned.

Parameters:

• sfreq (float) – sampling frequency which determines the time step when next_sample is called.
• intercept (float) – constant intercept of the signal
• freq_arr (np.ndarray of float) – array with frequencies of components included in the signal
• ampl_arr (np.ndarray of float) – array with amplitudes of components included in the signal
• phase_ini_arr (np.ndarray of float) – array with initial phases of components included in the signal
• noisy (bool) – boolean to determine whether the generated signal should be noisy or “clean” defaults to True

class agentMET4FOF.metrological_streams.MetrologicalSineGenerator(sfreq: int = 500, sine_freq: float = 50, device_id: str = 'SineGenerator', time_name: str = 'time', time_unit: str = 's', quantity_names: Union[str, Tuple[str, ...]] = 'Voltage', quantity_units: Union[str, Tuple[str, ...]] = 'V', misc: Optional[Any] = 'Simple sine wave generator', value_unc: float = 0.1, time_unc: float = 0)

Built-in class of sine wave generator

Parameters:

• sfreq (int, optional) – Sampling frequency which determines the time step when next_sample() is called. Defaults to 500.
• sine_freq (float, optional) – Frequency of the wave function. Defaults to 50.
• device_id (str, optional) – Name of the represented generator. Defaults to ‘SineGenerator’.
• time_name (str, optional) – Name for the time dimension. Defaults to ‘time’.
• time_unit (str, optional) – Unit for the time. Defaults to ‘s’.
• quantity_names (iterable of str or str, optional) – An iterable of names of the represented quantities’ values. Defaults to (‘Voltage’)
• quantity_units (iterable of str or str, optional) – An iterable of units for the quantities’ values. Defaults to (‘V’)
• misc (Any, optional) – This parameter can take any additional metadata which will be handed over to the corresponding attribute of the created Metadata object. Defaults to ‘Simple sine wave generator’.
• value_unc (iterable of floats or float, optional) – standard uncertainty(ies) of the quantity values. Defaults to 0.1.
• time_unc (iterable of floats or float, optional) – standard uncertainty of the time stamps. Defaults to 0.

_sine_wave_function(time, sine_freq)

A simple sine wave generator