sdynpy.core.sdynpy_data.NDDataArray

class NDDataArray(shape, nelements, data_dimension, ordinate_dtype='float64', buffer=None, offset=0, strides=None, order=None)

Bases: SdynpyArray

Generic N-Dimensional data structure

This data structure can contain real or complex data. More specific SDynPy data arrays inherit from this superclass.

__init__()

Methods

argmax([reduction])	Returns the index of the maximum ordinate in the data array
argmin([reduction])	Returns the index of the minimum ordinate in the data array
downsample(factor)	Downsample a signal by keeping only every n-th abscissa/ordinate pair.
extract_elements(indices)	Parses elements from the data array specified by the passed indices
extract_elements_by_abscissa(min_abscissa, ...)	Extracts elements with abscissa values within the specified range
from_uff(unv_data_dict[, squeeze])	Create a data array from a unv dictionary from read_unv
from_unv(unv_data_dict[, squeeze])	Create a data array from a unv dictionary from read_unv
get_drive_points([return_indices])	Returns data arrays where the reference is equal to the response
get_reciprocal_data([return_indices])	Gets reciprocal pairs of data from an NDDataArray.
interpolate(interpolated_abscissa[, kind])	Interpolates the NDDataArray using SciPy's interp1d.
join(data_arrays[, increment_abscissa])	Joins several data arrays together by concatenating their ordinates
load(filename)	Load in the specified file into a SDynPy array object
max([reduction])	Returns the maximum ordinate in the data array
min([reduction])	Returns the minimum ordinate in the data array
plot([one_axis, subplots_kwargs, ...])	Plot the data array
plot_image([ax, reduction_function, ...])
reshape_to_matrix([error_if_missing])	Reshapes a data array to a matrix with response coordinates along the rows and reference coordinates along the columns
save(filename)	Save the array to a numpy file
to_imat_struct([Version, SetRecord, ...])	Creates a Matlab structure that can be read the IMAT toolbox.
to_imat_struct_array([Version, SetRecord, ...])	Creates a Matlab structure that can be read the IMAT toolbox.
to_shape_array([abscissa_values])	Converts an NDDataArray to a ShapeArray
transform_coordinate_system(...[, ...])	Performs coordinate system transformations on the data
validate_common_abscissa(**allclose_kwargs)	Returns True if all functions have the same abscissa
zero_pad([num_samples, update_abscissa, ...])	Add zeros to the beginning or end of a signal

Attributes

abscissa_spacing	The spacing of the abscissa in the function.
data_dimension	Number of dimensions to the data
function_type	Returns the function type of the data array as a FunctionTypes Enum
idx_by_ab	AbscissaValueExtractor that can be indexed to extract an abscissa range
idx_by_el	AbscissaIndexExtractor that can be indexed to extract specific elements
num_coordinates	Number of coordinates defining the data array
num_elements	Number of elements in each data array
reference_coordinate	CoordinateArray corresponding to the response coordinates
response_coordinate	CoordinateArray corresponding to the response coordinates

property abscissa_spacing

The spacing of the abscissa in the function. Returns ValueError if abscissa are not evenly spaced.

argmax(reduction=None, *argmax_args, **argmax_kwargs)

Returns the index of the maximum ordinate in the data array

Parameters

• reduction (function, optional) – Optional function to modify the data, e.g. to select maximum of the absolute value. The default is None.

• *argmax_args (various) – Additional arguments passed to np.argmax

• **argmax_kwargs (various) – Additional keyword arguments passed to np.argmax

Returns

Index of the maximum of the flattened ordinate. Use np.unravel_index with self.ordinate.shape to get the unflattened index.

Return type

int

argmin(reduction=None, *argmin_args, **argmin_kwargs)

Returns the index of the minimum ordinate in the data array

Parameters

• reduction (function, optional) – Optional function to modify the data, e.g. to select minimum of the absolute value. The default is None.

• *argmin_args (various) – Additional arguments passed to np.argmax

• **argmin_kwargs (various) – Additional keyword arguments passed to np.argmax

Returns

Index of the minimum of the flattened ordinate. Use np.unravel_index with self.ordinate.shape to get the unflattened index.

Return type

int

property data_dimension

Number of dimensions to the data

downsample(factor)

Downsample a signal by keeping only every n-th abscissa/ordinate pair.

Parameters

factor (int) – Downsample factor. Only the factor-th abcissa will be kept.

Returns

The downsampled data object

Return type

NDDataArray

extract_elements(indices)

Parses elements from the data array specified by the passed indices

Parameters

indices – Any type of indices into a np.ndarray to select the elements to keep

Returns

Array reduced to specified elements

Return type

NDDataArray

extract_elements_by_abscissa(min_abscissa, max_abscissa)

Extracts elements with abscissa values within the specified range

Parameters

• min_abscissa (float) – Minimum abscissa value to keep

• max_abscissa (float) – Maximum abscissa value to keep.

Returns

Array reduced to specified elements.

Return type

NDDataArray

static from_uff(unv_data_dict, squeeze=True)

Create a data array from a unv dictionary from read_unv

Parameters

• unv_data_dict (dict) – Dictionary containing data from read_unv

• squeeze (bool, optional) – Automatically reduce dimension of the read data if possible. The default is True.

Returns

return_functions – Data read from unv

Return type

NDDataArray

static from_unv(unv_data_dict, squeeze=True)

Create a data array from a unv dictionary from read_unv

Parameters

• unv_data_dict (dict) – Dictionary containing data from read_unv

• squeeze (bool, optional) – Automatically reduce dimension of the read data if possible. The default is True.

Returns

return_functions – Data read from unv

Return type

NDDataArray

property function_type

Returns the function type of the data array as a FunctionTypes Enum

get_drive_points(return_indices=False)

Returns data arrays where the reference is equal to the response

Parameters

return_indices (bool, optional) – If True, it will return a set of indices into the original array that extract the drive point functions. If False, then the drive point functions are returned directly. The default is False.

Raises

ValueError – If the data does not have reference and response coordinates, the method will raise a ValueError.

Returns

If return_indices is True, this will return the indices into the original array that extract the drive point data. If return_indices is False, this will return the drive point NDDataArrays directly.

Return type

np.ndarray or NDDataArray subclass

get_reciprocal_data(return_indices=False)

Gets reciprocal pairs of data from an NDDataArray.

Parameters

return_indices (bool, optional) – If True, it will return a set of indices into the original array that extract the reciprocal functions. If False, then the reciprocal functions are returned directly. The default is False.

Raises

ValueError – If the data does not have reference and response coordinates, the method will raise a ValueError.

Returns

If return_indices is True, this will return the indices into the original array that extract the reciprocal data. If return_indices is False, this will return the reciprocal NDDataArrays directly.

Return type

np.ndarray or NDDataArray subclass

property idx_by_ab

AbscissaValueExtractor that can be indexed to extract an abscissa range

property idx_by_el

AbscissaIndexExtractor that can be indexed to extract specific elements

interpolate(interpolated_abscissa, kind='linear', **kwargs)

Interpolates the NDDataArray using SciPy’s interp1d.

Parameters

• interpolated_abscissa (ndarray) – Abscissa values at which to interpolate the function. If multi-dimensional, it will be flattened.

• kind (str or int, optional) – Specifies the kind of interpolation as a string or as an integer specifying the order of the spline interpolator to use. The string has to be one of ‘linear’, ‘nearest’, ‘nearest-up’, ‘zero’, ‘slinear’, ‘quadratic’, ‘cubic’, ‘previous’, or ‘next’. ‘zero’, ‘slinear’, ‘quadratic’ and ‘cubic’ refer to a spline interpolation of zeroth, first, second or third order; ‘previous’ and ‘next’ simply return the previous or next value of the point; ‘nearest-up’ and ‘nearest’ differ when interpolating half-integers (e.g. 0.5, 1.5) in that ‘nearest-up’ rounds up and ‘nearest’ rounds down. Default is ‘linear’.

• **kwargs – Additional arguments to scipy.interpolate.interp1d.

Returns

Array with interpolated arguments

Return type

NDDataArray

classmethod join(data_arrays, increment_abscissa=True)

Joins several data arrays together by concatenating their ordinates

Parameters

• data_arrays (NDDataArray) – Arrays to concatenate

• increment_abscissa (bool, optional) – Determines how the abscissa concatenation is handled. If False, the abscissa is left as it was in the original functions. If True, it will be incremented so it is continuous.

Return type

NDDataArray subclass

classmethod load(filename)

Load in the specified file into a SDynPy array object

Parameters

filename (str) – Filename specifying the file to load. If the filename has extension .unv or .uff, it will be loaded as a universal file. Otherwise, it will be loaded as a NumPy file.

Raises

AttributeError – Raised if a unv file is loaded from a class that does not have a from_unv attribute defined.

Returns

SDynpy array of the appropriate type from the loaded file.

Return type

cls

max(reduction=None, *max_args, **max_kwargs)

Returns the maximum ordinate in the data array

Parameters

• reduction (function, optional) – Optional function to modify the data, e.g. to select maximum of the absolute value. The default is None.

• *max_args (various) – Additional arguments passed to np.max

• **max_kwargs (various) – Additional keyword arguments passed to np.max

Returns

Maximum value in the ordinate.

Return type

Value

min(reduction=None, *min_args, **min_kwargs)

Returns the minimum ordinate in the data array

Parameters

• reduction (function, optional) – Optional function to modify the data, e.g. to select minimum of the absolute value. The default is None.

• *min_args (various) – Additional arguments passed to np.min

• **min_kwargs (various) – Additional keyword arguments passed to np.min

Returns

Minimum value in the ordinate.

Return type

Value

property num_coordinates

Number of coordinates defining the data array

property num_elements

Number of elements in each data array

plot(one_axis: bool = True, subplots_kwargs: dict = {}, plot_kwargs: dict = {}, abscissa_markers=None, abscissa_marker_labels=None, abscissa_marker_type='vline', abscissa_marker_plot_kwargs={})

Plot the data array

Parameters

• one_axis (bool, optional) – Set to True to plot all data on one axis. Set to False to plot data on multiple subplots. one_axis can also be set to a matplotlib axis to plot data on an existing axis. The default is True.

• subplots_kwargs (dict, optional) – Keywords passed to the matplotlib subplots function to create the figure and axes. The default is {}.

• plot_kwargs (dict, optional) – Keywords passed to the matplotlib plot function. The default is {}.

• abscissa_markers (ndarray, optional) – Array containing abscissa values to mark on the plot to denote significant events.

• abscissa_marker_labels (str or ndarray) – Array of strings to label the abscissa_markers with, or alternatively a format string that accepts index and abscissa inputs (e.g. ‘{index:}: {abscissa:0.2f}’). By default no label will be applied.

• abscissa_marker_type (str) – The type of marker to use. This can either be the string ‘vline’ or a valid matplotlib symbol specifier (e.g. ‘o’, ‘x’, ‘.’).

• abscissa_marker_plot_kwargs (dict) – Additional keyword arguments used when plotting the abscissa label markers.

Returns

axis – On which the data were plotted

Return type

matplotlib axis or array of axes

plot_image(ax=None, reduction_function=None, colorbar_scale='linear', colorbar_min=None, colorbar_max=None)

property reference_coordinate

CoordinateArray corresponding to the response coordinates

reshape_to_matrix(error_if_missing=True)

Reshapes a data array to a matrix with response coordinates along the rows and reference coordinates along the columns

Parameters

error_if_missing (bool) – If True, an error will be thrown if there are missing data objects when trying to make a matrix of functions (i.e. if a response degree of freedom is missing from one reference). If False, response coordinates will simply be discarded if they do not exist for all references. Default is True.

Returns

output_array – 2D Array of NDDataArray

Return type

Data Aarray

property response_coordinate

CoordinateArray corresponding to the response coordinates

save(filename)

Save the array to a numpy file

Parameters

filename (str) – Filename that the array will be saved to. Will be appended with .npz if not specified in the filename

to_imat_struct(Version=None, SetRecord=None, CreateDate: Optional[datetime] = None, ModifyDate: Optional[datetime] = None, OwnerName=None, AbscissaDataType=None, AbscissaTypeQual=None, AbscissaAxisLab=None, AbscissaUnitsLab=None, OrdNumDataType=None, OrdNumTypeQual=None, OrdDenDataType=None, OrdDenTypeQual=None, OrdinateAxisLab=None, OrdinateUnitsLab=None, ZAxisDataType=None, ZAxisTypeQual=None, ZGeneralValue=None, ZRPMValue=None, ZOrderValue=None, ZTimeValue=None, UserValue1=None, UserValue2=None, UserValue3=None, UserValue4=None, SamplingType=None, WeightingType=None, WindowType=None, AmplitudeUnits=None, Normalization=None, OctaveFormat=None, OctaveAvgType=None, ExpDampingFact=None, PulsesPerRev=None, MeasurementRun=None, LoadCase=None, IRIGTime=None)

Creates a Matlab structure that can be read the IMAT toolbox.

This structure can be read by the IMAT toolbox in Matlab to create an imat_fn object. Note this is generally a faster function than to_imat_struct_array.

Parameters

• Version (TYPE, optional) – DESCRIPTION. The default is None.

• SetRecord (TYPE, optional) – DESCRIPTION. The default is None.

• CreateDate (datetime, optional) – DESCRIPTION. The default is None.

• ModifyDate (datetime, optional) – DESCRIPTION. The default is None.

• OwnerName (TYPE, optional) – DESCRIPTION. The default is None.

• AbscissaDataType (TYPE, optional) – DESCRIPTION. The default is None.

• AbscissaTypeQual (TYPE, optional) – DESCRIPTION. The default is None.

• AbscissaAxisLab (TYPE, optional) – DESCRIPTION. The default is None.

• AbscissaUnitsLab (TYPE, optional) – DESCRIPTION. The default is None.

• OrdNumDataType (TYPE, optional) – DESCRIPTION. The default is None.

• OrdNumTypeQual (TYPE, optional) – DESCRIPTION. The default is None.

• OrdDenDataType (TYPE, optional) – DESCRIPTION. The default is None.

• OrdDenTypeQual (TYPE, optional) – DESCRIPTION. The default is None.

• OrdinateAxisLab (TYPE, optional) – DESCRIPTION. The default is None.

• OrdinateUnitsLab (TYPE, optional) – DESCRIPTION. The default is None.

• ZAxisDataType (TYPE, optional) – DESCRIPTION. The default is None.

• ZAxisTypeQual (TYPE, optional) – DESCRIPTION. The default is None.

• ZGeneralValue (TYPE, optional) – DESCRIPTION. The default is None.

• ZRPMValue (TYPE, optional) – DESCRIPTION. The default is None.

• ZOrderValue (TYPE, optional) – DESCRIPTION. The default is None.

• ZTimeValue (TYPE, optional) – DESCRIPTION. The default is None.

• UserValue1 (TYPE, optional) – DESCRIPTION. The default is None.

• UserValue2 (TYPE, optional) – DESCRIPTION. The default is None.

• UserValue3 (TYPE, optional) – DESCRIPTION. The default is None.

• UserValue4 (TYPE, optional) – DESCRIPTION. The default is None.

• SamplingType (TYPE, optional) – DESCRIPTION. The default is None.

• WeightingType (TYPE, optional) – DESCRIPTION. The default is None.

• WindowType (TYPE, optional) – DESCRIPTION. The default is None.

• AmplitudeUnits (TYPE, optional) – DESCRIPTION. The default is None.

• Normalization (TYPE, optional) – DESCRIPTION. The default is None.

• OctaveFormat (TYPE, optional) – DESCRIPTION. The default is None.

• OctaveAvgType (TYPE, optional) – DESCRIPTION. The default is None.

• ExpDampingFact (TYPE, optional) – DESCRIPTION. The default is None.

• PulsesPerRev (TYPE, optional) – DESCRIPTION. The default is None.

• MeasurementRun (TYPE, optional) – DESCRIPTION. The default is None.

• LoadCase (TYPE, optional) – DESCRIPTION. The default is None.

• IRIGTime (TYPE, optional) – DESCRIPTION. The default is None.

Returns

data_dict – DESCRIPTION.

Return type

TYPE

to_imat_struct_array(Version=1, SetRecord=0, CreateDate: Optional[datetime] = None, ModifyDate: Optional[datetime] = None, OwnerName='', AbscissaDataType=SpecificDataType.UNKNOWN, AbscissaTypeQual=TypeQual.TRANSLATION, AbscissaAxisLab='', AbscissaUnitsLab='', OrdNumDataType=SpecificDataType.UNKNOWN, OrdNumTypeQual=TypeQual.TRANSLATION, OrdDenDataType=SpecificDataType.UNKNOWN, OrdDenTypeQual=TypeQual.TRANSLATION, OrdinateAxisLab='', OrdinateUnitsLab='', ZAxisDataType=SpecificDataType.UNKNOWN, ZAxisTypeQual=TypeQual.TRANSLATION, ZGeneralValue=0, ZRPMValue=0, ZOrderValue=0, ZTimeValue=0, UserValue1=0, UserValue2=0, UserValue3=0, UserValue4=0, SamplingType='Dynamic', WeightingType='None', WindowType='None', AmplitudeUnits='Unknown', Normalization='Unknown', OctaveFormat=0, OctaveAvgType='None', ExpDampingFact=0, PulsesPerRev=0, MeasurementRun=0, LoadCase=0, IRIGTime='', verbose=False)

Creates a Matlab structure that can be read the IMAT toolbox.

This structure can be read by the IMAT toolbox in Matlab to create an imat_fn object. Note this is generally a slower function than to_imat_struct.

Parameters

• Version (int, optional) – The version number of the function. The default is 1.

• SetRecord (int, optional) – The set record of the function. The default is 0.

• CreateDate (datetime, optional) – The date that the function was created. The default is Now.

• ModifyDate (datetime, optional) – The date that the function was modified. The default is Now.

• OwnerName (str, optional) – The owner of the dataset. The default is ‘’.

• AbscissaDataType (SpecificDataType, optional) – The type of data associated with the Abscissa of the function. The default is SpecificDataType.UNKNOWN.

• AbscissaTypeQual (TypeQual, optional) – The qualifier associated with the abscissa of the function. The default is TypeQual.TRANSLATION.

• AbscissaAxisLab (str, optional) – String used to label the abscissa axis. The default is ‘’.

• AbscissaUnitsLab (str, optional) – String used to label the units on the abscissa axis. The default is ‘’.

• OrdNumDataType (SpecificDataType, optional) – The type of data associated with the numerator of the ordinate of the function. The default is SpecificDataType.UNKNOWN.

• OrdNumTypeQual (TypeQual, optional) – The qualifier associated with the numerator of the ordinate of the function. The default is TypeQual.TRANSLATION.

• OrdDenDataType (SpecificDataType, optional) – The type of data associated with the denominator of the ordinate of the function. The default is SpecificDataType.UNKNOWN.

• OrdDenTypeQual (TypeQual, optional) – The qualifier associated with the denominator of the ordinate of the function. The default is TypeQual.TRANSLATION.

• OrdinateAxisLab (str, optional) – String used to label the ordinate axis. The default is ‘’.

• OrdinateUnitsLab (TYPE, optional) – String used to label the units on the ordinate axis. The default is ‘’.

• ZAxisDataType (TYPE, optional) – DESCRIPTION. The default is SpecificDataType.UNKNOWN.

• ZAxisTypeQual (TYPE, optional) – DESCRIPTION. The default is TypeQual.TRANSLATION.

• ZGeneralValue (TYPE, optional) – DESCRIPTION. The default is 0.

• ZRPMValue (TYPE, optional) – DESCRIPTION. The default is 0.

• ZOrderValue (TYPE, optional) – DESCRIPTION. The default is 0.

• ZTimeValue (TYPE, optional) – DESCRIPTION. The default is 0.

• UserValue1 (TYPE, optional) – DESCRIPTION. The default is 0.

• UserValue2 (TYPE, optional) – DESCRIPTION. The default is 0.

• UserValue3 (TYPE, optional) – DESCRIPTION. The default is 0.

• UserValue4 (TYPE, optional) – DESCRIPTION. The default is 0.

• SamplingType (TYPE, optional) – DESCRIPTION. The default is ‘Dynamic’.

• WeightingType (TYPE, optional) – DESCRIPTION. The default is ‘None’.

• WindowType (TYPE, optional) – DESCRIPTION. The default is ‘None’.

• AmplitudeUnits (TYPE, optional) – DESCRIPTION. The default is ‘Unknown’.

• Normalization (TYPE, optional) – DESCRIPTION. The default is ‘Unknown’.

• OctaveFormat (TYPE, optional) – DESCRIPTION. The default is 0.

• OctaveAvgType (TYPE, optional) – DESCRIPTION. The default is ‘None’.

• ExpDampingFact (TYPE, optional) – DESCRIPTION. The default is 0.

• PulsesPerRev (TYPE, optional) – DESCRIPTION. The default is 0.

• MeasurementRun (TYPE, optional) – DESCRIPTION. The default is 0.

• LoadCase (TYPE, optional) – DESCRIPTION. The default is 0.

• IRIGTime (TYPE, optional) – DESCRIPTION. The default is ‘’.

• verbose (TYPE, optional) – DESCRIPTION. The default is False.

Returns

output_struct – A numpy structured array that can be saved to a mat file using scipy.io.savemat.

Return type

np.ndarray

to_shape_array(abscissa_values=None)

Converts an NDDataArray to a ShapeArray

Parameters

abscissa_values (ndarray, optional) – Abscissa values at which the shapes will be created. The default is to create shapes at all abscissa values. If an entry in abscissa_values does not match a value in abscissa, the closest abscissa value will be selected

Raises

ValueError – If the data does not have common abscissa across all functions or if duplicate response coordinates occur in the NDDataArray

Returns

ShapeArray containing the NDDataArray’s ordinate as its shape_matrix

Return type

ShapeArray

transform_coordinate_system(original_geometry, new_geometry, node_id_map=None, rotations=False)

Performs coordinate system transformations on the data

Parameters

• original_geometry (Geometry) – The Geometry in which the shapes are currently defined

• new_geometry (Geometry) – The Geometry in which the shapes are desired to be defined

• node_id_map (id_map, optional) – If the original and new geometries do not have common node ids, an id_map can be specified to map the original geometry node ids to new geometry node ids. The default is None, which means no mapping will occur, and the geometries have common id numbers.

• rotations (bool, optional) – If True, also transform rotational degrees of freedom. The default is False.

Returns

A NDDataArray that can now be plotted with the new geometry

Return type

NDDataArray or Subclass

validate_common_abscissa(**allclose_kwargs)

Returns True if all functions have the same abscissa

Parameters

**allclose_kwargs (various) – Arguments to np.allclose to specify tolerances

Returns

True if all functions have the same abscissa

Return type

bool

zero_pad(num_samples=0, update_abscissa=True, left=False, right=True, use_next_fast_len=False)

Add zeros to the beginning or end of a signal

Parameters

• num_samples (int, optional) – Number of zeros to add to the function. If not specified, no zeros are added unless use_next_fast_len is True

• update_abscissa (bool, optional) – If True, modify the abscissa to keep the same abscissa spacing. The function must have equally spaced abscissa for this to work. If False, the added abscissa will have a value of zero. The default is True.

• left (bool, optional) – Add zeros to the left side (beginning) of the function. The default is False. If both left and right are specified, the zeros will be split half on the left and half on the right.

• right (bool, optional) – Add zeros to the right side (end) of the function. The default is True. If both left and right are specified, the zeros will be split half on the left and half on the right

• use_next_fast_len (bool, optional) – If True, potentially add additional zeros to the value specified by num_samples to allow the total length of the final signal to reach fast values for FFT as specified by scipy.fft.next_fast_len.

Returns

The zero-padded version of the function

Return type

NDDataArray subclass