pyspecdata.core.nddata

class pyspecdata.core.nddata(*args, **kwargs)

This is the detailed API reference. For an introduction on how to use ND-Data, see the Main ND-Data Documentation.

__init__(*args, **kwargs)

initialize nddata – several options. Depending on the information available, one of several formats can be used.

3 arguments:

nddata(inputarray, shape, dimlabels)

inputarray:ndarray storing the data – note that the size is ignored and the data is reshaped as needed shape:a list (or array, etc.) giving the size of each dimension, in order dimlabels:a list giving the names of each dimension, in order

2 arguments:

nddata(inputarray, dimlabels)

inputarray:ndarray storing the data – the data is not reshaped dimlabels:a list giving the names of each dimension, in order

2 arguments:

nddata(inputarray, single_dimlabel)

inputarray:ndarray storing the data – must be 1D inputarray is also used to label the single axis single_dimlabel:  a list giving the name of the single axis

1 argument:

nddata(inputarray, shape, dimlabels)

inputarray:ndarray storing the data – reduced to 1D A single dimension, called “INDEX” is set. This suppresses the printing of axis labels. This is used to store numbers and arrays that might have error and units, but aren’t gridded data.

keyword args

these can be used to set the labels, etc, and are passed to __my_init__()

Methods

__init__(*args, **kwargs)	initialize nddata – several options.
add_noise(intensity)	Add Gaussian (box-muller) noise to the data.
aligndata(arg)	This is a fundamental method used by all of the arithmetic operations.
argmax(*args, **kwargs)	find the max along a particular axis, and get rid of that axis, replacing it with the index number of the max value
argmin(*axes, **kwargs)	If argmin(‘axisname’) find the min along a particular axis, and get rid of that axis, replacing it with the index number of the max value.
axis(axisname)	returns a 1-D axis for further manipulation
axlen(axis)	return the size (length) of an axis, by name
axn(axis)	Return the index number for the axis with the name “axis”
cdf([normalized, max_bins])	calculate the Cumulative Distribution Function for the data along axis_name
check_axis_coords_errors()
chunk(axisin, *otherargs)	“Chunking” is defined here to be the opposite of taking a direct product, increasing the number of dimensions by the inverse of the process by which taking a direct product decreases the number of dimensions. This function chunks axisin into multiple new axes arguments.:
chunk_auto(axis_name, which_field[, dimname])	assuming that axis “axis_name” is currently labeled with a structured array, choose one field (“which_field”) of that structured array to generate a new dimension Note that for now, by definition, no error is allowed on the axes.
circshift(axis, amount)
contiguous(lambdafunc[, axis])	Return contiguous blocks that satisfy the condition given by lambdafunc
contour([labels])	Contour plot – kwargs are passed to the matplotlib contour function.
convolve(axisname, filterwidth[, convfunc])	Perform a convolution.
copy([data])	Return a full copy of this instance.
copy_axes(other)
copy_props(other)	Copy all properties (see get_prop()) from another nddata object – note that these include properties pertaining the the FT status of various dimensions.
copyaxes(other)
cropped_log([subplot_axes, magnitude])	For the purposes of plotting, this generates a copy where I take the log, spanning “magnitude” orders of magnitude This is designed to be called as abs(instance).cropped_log(), so it doesn’t make a copy
diff(thisaxis[, backwards])
dot(arg)	Tensor dot of self with arg – dot all matching dimension labels.
extend(axis, extent[, fill_with, tolerance])	If axis is uniformly ascending with spacing \(dx\), then extend by adding a point every \(dx\) until the axis includes the point extent.
extend_for_shear(altered_axis, propto_axis, …)	this is propto_axis helper function for .fourier.shear
fld(dict_in[, noscalar])	flatten dictionary – return list
fourier_shear(altered_axis, propto_axis, …)	the fourier shear method – see .shear() documentation
fromaxis(*args, **kwargs)	Generate an nddata object from one of the axis labels.
ft(axes[, tolerance, cosine, verbose])	This performs a Fourier transform along the axes identified by the string or list of strings axes.
ft_clear_startpoints(axis[, t, f, nearest])	Clears memory of where the origins in the time and frequency domain are.
ft_state_to_str(*axes)	Return a string that lists the FT domain for the given axes.
ftshift(axis, value)	FT-based shift.
get_covariance()	this returns the covariance matrix of the data
get_error(*args)	get a copy of the errors either set_error(‘axisname’,error_for_axis) or set_error(error_for_data)
get_ft_prop(axis[, propname])	Gets the FT property given by propname.
get_plot_color()
get_prop([propname])	return arbitrary ND-data properties (typically acquisition parameters etc.) by name (propname)
get_units(*args)
getaxis(axisname)
getaxisshape(axisname)
gnuplot_save(filename)
hdf5_write(h5path[, directory])	Write the nddata to an HDF5 file.
histogram(**kwargs)
human_units()
ift(axes[, n, tolerance, verbose])	This performs an inverse Fourier transform along the axes identified by the string or list of strings axes.
indices(axis_name, values)	Return a string of indeces that most closely match the axis labels corresponding to values.
inhomog_coords(direct_dim, indirect_dim[, …])	Apply the “inhomogeneity transform,” which rotates the data by \(45^{\circ}\), and then mirrors the portion with \(t_2<0\) in order to transform from a \((t_1,t_2)\) coordinate system to a \((t_{inh},t_{homog})\) coordinate system.
integrate(thisaxis[, backwards, cumulative])	Performs an integration – which is similar to a sum, except that it takes the axis into account, i.e., it performs: \(\int f(x) dx\) rather than \(\sum_i f(x_i)\)
interp(axis, axisvalues[, past_bounds, …])	interpolate data values given axis values
invinterp(axis, values, **kwargs)	interpolate axis values given data values
item()	like numpy item – returns a number when zero-dimensional
labels(*args)	label the dimensions, given in listofstrings with the axis labels given in listofaxes – listofaxes must be a numpy array; you can pass either a dictionary or a axis name (string)/axis label (numpy array) pair
like(value)	provide “zeros_like” and “ones_like” functionality
linear_shear(along_axis, propto_axis, shear_amnt)	the linear shear – see self.shear for documentation
matchdims(other)	add any dimensions to self that are not present in other
matrices_3d([also1d, invert, max_dimsize, …])	returns X,Y,Z,x_axis,y_axis matrices X,Y,Z, are suitable for a variety of mesh plotting, etc, routines x_axis and y_axis are the x and y axes
max()
mayavi_surf()	use the mayavi surf function, assuming that we’ve already loaded mlab during initialization
mean(*args, **kwargs)	Take the mean and (optionally) set the error to the standard deviation
mean_all_but(listofdims)	take the mean over all dimensions not in the list
mean_nopop(axis)
mean_weighted(axisname)	perform the weighted mean along axisname (use $sigma$ from $sigma = $self.get_error() do generate $1/sigma$ weights) for now, it clears the error of self, though it would be easy to calculate the new error, since everything is linear
meshplot([stride, alpha, onlycolor, light, …])	takes both rotation and light as elevation, azimuth only use the light kwarg to generate a black and white shading display
min()
mkd(*arg, **kwargs)	make dictionary format
multimin(minfunc, axisname, filterwidth, …)
name(*arg)	args: .name(newname) –> Name the object (for storage, etc) .name() –> Return the name
nnls(dimname, newaxis_dict, kernel_func[, l])	Perform regularized non-negative least-squares “fit” on self.
normalize(axis[, first_figure])
oldtimey([alpha, ax, linewidth, …])
plot_labels(labels[, fmt])	this only works for one axis now
polyfit(axis[, order, force_y_intercept])	polynomial fitting routine – return the coefficients and the fit ..note: later, should probably branch this off as a new type of fit class
popdim(dimname)
random_mask(axisname[, threshold, inversion])	generate a random mask with about ‘threshold’ of the points thrown out
register_axis(arg[, nearest])	Interpolate the data so that the given axes are in register with a set of specified values.
rename(previous, new)
reorder(*axes, **kwargs)	Reorder the dimensions the first arguments are a list of dimensions
replicate_units(other)
repwlabels(axis)
retaxis(axisname)
run(*args)	run a standard numpy function on the nddata:
run_avg(thisaxisname[, decimation, centered])	a simple running average
run_nopop(func, axis)
runcopy(*args)
secsy_transform(direct_dim, indirect_dim[, …])	Shift the time-domain data backwards by the echo time.
secsy_transform_manual(direct_dim, indirect_dim)	Shift the time-domain data backwards by the echo time.
set_error(*args)	set the errors: either
set_ft_prop(axis[, propname, value])	Sets the FT property given by propname.
set_plot_color(thiscolor)
set_prop(*args)	set a ‘property’ of the nddata This is where you can put all unstructured information (e.g.
set_to(otherinst)	Set data inside the current instance to that of the other instance.
set_units(*args)
setaxis(*args)	set or alter the value of the coordinate axis
shear(along_axis, propto_axis, shear_amnt[, …])	Shear the data \(s\):
smoosh(dimstocollapse[, dimname, noaxis])	Collapse (smoosh) multiple dimensions into one dimension.
sort(axisname[, reverse])
sort_and_xy()
squeeze([return_dropped])	squeeze singleton dimensions
sum(axes)
sum_nopop(axes)
to_ppm()	Function that converts from Hz to ppm using Bruker parameters
unitify_axis(axis_name[, is_axis])	this just generates an axis label with appropriate units
units_texsafe(*args)
unset_prop(arg)	remove a ‘property’
waterfall([alpha, ax, rotation, color, …])

Attributes

C	shortcut for copy
angle	Return the angle component of the data
imag	Return the imag component of the data
real	Return the real component of the data
want_to_prospa_decim_correct