sdynpy.fileio.sdynpy_rattlesnake.RattlesnakeRandomEnvironmentData

• Module: sdynpy.fileio.sdynpy_rattlesnake

• Source: GitHub

Signature¶

class sdynpy.fileio.sdynpy_rattlesnake.RattlesnakeRandomEnvironmentData(channel_coordinates: 'CoordinateArray', sysid_averages: 'int', samples_per_frame: 'int', cpsd_overlap: 'int', cpsd_window: 'str', specification_frequency_lines: 'np.ndarray', specification_cpsd_matrix: 'np.ndarray', specification_warning_matrix: 'np.ndarray', specification_abort_matrix: 'np.ndarray', control_channel_indices: 'np.ndarray', fft_lines: 'int', sysid_frame_size: 'int' = None, sysid_averaging_type: 'str' = None, sysid_noise_averages: 'int' = None, sysid_exponential_averaging_coefficient: 'float' = None, sysid_estimator: 'str' = None, sysid_level: 'float' = None, sysid_level_ramp_time: 'float' = None, sysid_signal_type: 'str' = None, sysid_window: 'str' = None, sysid_overlap: 'float' = None, sysid_burst_on: 'float' = None, sysid_pretrigger: 'float' = None, sysid_burst_ramp_fraction: 'float' = None, sysid_low_frequency_cutoff: 'float' = None, sysid_high_frequency_cutoff: 'float' = None, test_level_ramp_time: 'float' = None, update_tf_during_control: 'int' = None, cola_window: 'str' = None, cola_overlap: 'float' = None, cola_window_exponent: 'float' = None, frames_in_cpsd: 'int' = None, control_python_script: 'os.pathlike' = None, control_python_function: 'str' = None, control_python_function_type: 'int' = None, control_python_function_parameters: 'str' = None, allow_automatic_aborts: 'int' = None, specification_channels: 'int' = None, control_channels: 'int' = None, **kwargs)

Data for a Rattlesnake Random vibration environment.

Parses variables, dimensions, and attributes from the environment group of a Rattlesnake nc4 file and provides convenience properties that return sdynpy array objects.

Parameters¶

• channel_coordinates : CoordinateArray Coordinate array for all physical channels in the parent RattlesnakeData object. Used to resolve control-channel coordinates without storing a back-reference to the parent.

• sysid_averages : int Number of averages used during system identification.

• samples_per_frame : int Number of time samples per data frame.

• cpsd_overlap : int Overlap count used when computing the CPSD.

• cpsd_window : str Window function name applied before CPSD computation.

• specification_frequency_lines : np.ndarray Frequency axis (Hz) for the specification CPSD matrices.

• specification_cpsd_matrix : np.ndarray Target CPSD specification matrix with shape (n_freq, n_control, n_control).

• specification_warning_matrix : np.ndarray Warning-band CPSD matrix with shape (2, n_freq, n_control, n_control) where index 0 is the lower bound and index 1 is the upper bound.

• specification_abort_matrix : np.ndarray Abort-band CPSD matrix with shape (2, n_freq, n_control, n_control) where index 0 is the lower bound and index 1 is the upper bound.

• control_channel_indices : np.ndarray Integer indices into the parent channel table identifying the control channels for this environment.

• fft_lines : int Number of FFT frequency lines used in control.

• **kwargs

• Any additional nc4 attributes, variables, or dimensions not covered

• by the explicit parameters above are stored directly as instance

• attributes via __setattr__.

Attributes¶

control_coordinate¶

Coordinate array for the control channels of this environment.

When a response_transformation_matrix is present the coordinates are synthetic sequential nodes (1-based, direction 0) whose count equals the number of transformed virtual channels. Otherwise channel_coordinates is indexed by control_channel_indices to return the physical control-channel coordinates.

Returns¶

• CoordinateArray

• Coordinates for each control channel (or virtual transformed

• channel) in this environment.

specification_abort_psd¶

Upper and lower abort-band PSDs for this random environment.

Assembles two PowerSpectralDensityArray objects from the lower (index 0) and upper (index -1) slices of specification_abort_matrix along the first axis and concatenates them into a two-element array. Returns None when any required attribute is absent.

Returns¶

• PowerSpectralDensityArray or None

• Array with shape (2, n_control) where index 0 is the lower

• abort bound and index 1 is the upper abort bound, or None if

• specification_warning_matrix, control_coordinate, or

• specification_frequency_lines are not available.

specification_cpsd¶

Target CPSD specification for this random environment.

Assembles a square PowerSpectralDensityArray from the specification_cpsd_matrix and specification_frequency_lines attributes loaded from the nc4 file. Returns None when any of those attributes are absent.

Returns¶

• PowerSpectralDensityArray or None

• Square cross-power spectral density array with shape

• (n_control, n_control) at each frequency line, or None

• if the required attributes are not available.

specification_warning_psd¶

Upper and lower warning-band PSDs for this random environment.

Assembles two PowerSpectralDensityArray objects from the lower (index 0) and upper (index -1) slices of specification_warning_matrix along the first axis and concatenates them into a two-element array. Returns None when any required attribute is absent.

Returns¶

• PowerSpectralDensityArray or None

• Array with shape (2, n_control) where index 0 is the lower

• warning bound and index 1 is the upper warning bound, or None

• if specification_abort_matrix, control_coordinate, or

• specification_frequency_lines are not available.

Methods¶

__init__¶

• Source: GitHub

def sdynpy.fileio.sdynpy_rattlesnake.RattlesnakeRandomEnvironmentData.__init__(self, channel_coordinates: 'CoordinateArray', sysid_averages: 'int', samples_per_frame: 'int', cpsd_overlap: 'int', cpsd_window: 'str', specification_frequency_lines: 'np.ndarray', specification_cpsd_matrix: 'np.ndarray', specification_warning_matrix: 'np.ndarray', specification_abort_matrix: 'np.ndarray', control_channel_indices: 'np.ndarray', fft_lines: 'int', sysid_frame_size: 'int' = None, sysid_averaging_type: 'str' = None, sysid_noise_averages: 'int' = None, sysid_exponential_averaging_coefficient: 'float' = None, sysid_estimator: 'str' = None, sysid_level: 'float' = None, sysid_level_ramp_time: 'float' = None, sysid_signal_type: 'str' = None, sysid_window: 'str' = None, sysid_overlap: 'float' = None, sysid_burst_on: 'float' = None, sysid_pretrigger: 'float' = None, sysid_burst_ramp_fraction: 'float' = None, sysid_low_frequency_cutoff: 'float' = None, sysid_high_frequency_cutoff: 'float' = None, test_level_ramp_time: 'float' = None, update_tf_during_control: 'int' = None, cola_window: 'str' = None, cola_overlap: 'float' = None, cola_window_exponent: 'float' = None, frames_in_cpsd: 'int' = None, control_python_script: 'os.pathlike' = None, control_python_function: 'str' = None, control_python_function_type: 'int' = None, control_python_function_parameters: 'str' = None, allow_automatic_aborts: 'int' = None, specification_channels: 'int' = None, control_channels: 'int' = None, **kwargs)

Store all environment parameters as instance attributes.

Every named parameter is assigned directly to self. Any additional keyword arguments (extra nc4 attributes, variables, or dimensions) are stored via __setattr__.

load_from_env_group¶

• Source: GitHub

def sdynpy.fileio.sdynpy_rattlesnake.RattlesnakeRandomEnvironmentData.load_from_env_group(cls, parent: "'RattlesnakeData'", env_group: 'nc4.Group') -> "'RattlesnakeRandomEnvironmentData'"

Construct an instance by reading all data from an nc4 environment group.

Loads nc4 attributes, variables (including complex split-variable pairs stored as <name>_real / <name>_imag), and dimension sizes from env_group, then calls the constructor with channel_coordinates=parent.coordinate.

Parameters¶

• parent : RattlesnakeData The top-level data object whose coordinate property provides the full physical-channel coordinate array.

• env_group : netCDF4.Group The nc4 group for this environment (e.g. data['Random']).

Returns¶

• RattlesnakeRandomEnvironmentData

• Fully populated environment data object.