astrodendro.structure.Structure¶

class astrodendro.structure.Structure(indices, values, children=[], idx=None, dendrogram=None)¶

A structure in the dendrogram, for example a leaf or a branch.

A structure that is part of a dendrogram knows which other structures it is related to. For example, it is possible to get the parent structure containing the present structure s by using the parent attribute:

>>> s.parent
<Structure type=branch idx=2152>

Likewise, the children attribute can be used to get a list of all sub-structures:

>>> s.children
[<Structure type=branch idx=1680>, <Structure type=branch idx=5771>]

A number of attributes and methods are available to explore the structure in more detail, such as the indices and values methods, which return the indices and values of the pixels that are part of the structure. These and other methods have a subtree= option, which if True (the default) returns the quantities related to structure and all sub-structures, and if False includes only the pixels that are part of the structure, but excluding any sub-structure.

Attributes

`is_leaf`	Whether the present structure is a leaf.
`is_branch`	Whether the present structure is a branch.
`vmin`	The minimum value of pixels belonging to the branch (excluding sub-structure).
`vmax`	The maximum value of pixels belonging to the branch (excluding sub-structure).
`height`	This is defined as the minimum value in the children structures, or the peak value of the present structure if it has no children.
`ancestor`	Find the ancestor of this leaf/branch non-recursively.
`parent`	The parent structure containing the present structure.
`children`	A list of all the sub-structures contained in the present structure.
`descendants`	Get a flattened list of all child leaves and branches.
`level`	The level of the structure, i.e.
`newick`

Methods

`indices`([subtree])	The indices of the pixels in this branch.
`values`([subtree])	The values of the pixels in this branch.
`get_npix`([subtree])	Return the number of pixels in this structure.
`get_peak`([subtree])	Return (index, value) for the pixel with maximum value.
`sorted_leaves`([sort_key, reverse, subtree])	Return a list of sorted leaves.
`get_mask`([shape, subtree])	Return a boolean mask outlining the structure.

Methods (detail)

indices(subtree=True)¶

The indices of the pixels in this branch.

Parameters:

subtree : bool, optional

Whether to recursively include all sub-structures

values(subtree=True)¶

The values of the pixels in this branch.

Parameters:

subtree : bool, optional

Whether to recursively include all sub-structures

get_npix(subtree=True)¶

Return the number of pixels in this structure.

Parameters:

subtree : bool, optional

Whether to recursively include all sub-structures when counting the pixels.

Returns:

n_pix : int

The number of pixels in this structure

get_peak(subtree=True)¶

Return (index, value) for the pixel with maximum value.

Parameters:

subtree : bool, optional

Whether to recursively include all sub-structures when searching for the peak.

Returns:

index : tuple

The n-dimensional index of the peak pixel

value : float

The value of the peak pixel

sorted_leaves(sort_key=<function <lambda>>, reverse=False, subtree=True)¶

Return a list of sorted leaves.

Parameters:

sort_key : function, optional

A function which given a structure will return a scalar that is then used for sorting. By default, this is set to a function that returns the peak value of a structure (including descendants).

reverse : bool, optional

Whether to reverse the sorting.

subtree : bool, optional

Whether to recursively include all sub-structures in the list.

Returns:

leaves : list

A list of sorted leaves

get_mask(shape=None, subtree=True)¶

Return a boolean mask outlining the structure.

Parameters:

shape : tuple, optional

The shape of the array upon which to compute the mask. This is only required if the structure is not attached to a dendrogram.

subtree : bool, optional

Whether to recursively include all sub-structures in the mask.

Returns:

mask : ndarray

The mask outlining the structure (False values are used outside the structure, and True values inside).