pyspinw.util

Generally helpful functions that don’t obviously live anywhere else in particular

Functions

arraylike_equality(array_1, array_2[, abs_tol])	Check for approximate equality of arrays that may or may not have the same shape
connected_components(adjacency_matrix)	Get the connected components of a graph specied by an adjacency matrix
demo_triple_product_matrix()	Show an example of making a matrix that does the triple product
is_diagonal(m)	Check whether an array is diagonal
problematic_sites(sites, implied_sites, ...)	Find sites that are contradictory in terms of magnetism
rotation_from_z(target_vector)	Rotation matrix from (0,0,1) to the target vector direction
rotation_matrix(angle, axis)	Create a rotation matrix
triple_product_matrix(v)	Find the matrix, M, such that for all vectors X, Y

Classes

IncrementalPointHistogram([tolerance])

Histogramming method for finding nearest neighbour distances in lattices

class pyspinw.util.IncrementalPointHistogram(tolerance=1e-10)

Bases: Generic[T]

Histogramming method for finding nearest neighbour distances in lattices

add(distance, entry: T)

Add an entry to the collection

group_sizes()

Size of each group

groups()

Groups in order of distance

n_groups()

Number of groups at different distances

pyspinw.util.arraylike_equality(array_1: ArrayLike, array_2: ArrayLike, abs_tol=1e-08)

Check for approximate equality of arrays that may or may not have the same shape

pyspinw.util.connected_components(adjacency_matrix: ndarray) → list[list[int]]

Get the connected components of a graph specied by an adjacency matrix

Parameters:

adjacency_matrix – n-by-n numpy array of dtype bool representing the adjacency matrix

Returns:

list of subgraphs, themselves lists of indices for the adjacency matrix

pyspinw.util.demo_triple_product_matrix()

Show an example of making a matrix that does the triple product

pyspinw.util.is_diagonal(m: ndarray)

Check whether an array is diagonal

pyspinw.util.problematic_sites(sites: list[Site], implied_sites: list[Site], site_to_implied_site: list[list[int]])

Find sites that are contradictory in terms of magnetism

These sites have an image with same position but negated spin

Parameters:

• sites – Asymmetric cell sites

• implied_sites – Sites inferred by symmetry

• site_to_implied_site – mapping from site index to implied site index

Returns:

Indices of sites with this problem

pyspinw.util.rotation_from_z(target_vector)

Rotation matrix from (0,0,1) to the target vector direction

pyspinw.util.rotation_matrix(angle, axis)

Create a rotation matrix

pyspinw.util.triple_product_matrix(v: ndarray)

Find the matrix, M, such that for all vectors X, Y

X^T M Y = V . (X x Y)