spinedb_api.graph_layout_generator

This module defines the GraphLayoutGenerator class.

Module Contents

Classes

GraphLayoutGenerator

A class to build an optimised layout for an undirected graph.
class spinedb_api.graph_layout_generator.GraphLayoutGenerator(vertex_count, src_inds=(), dst_inds=(), spread=0, heavy_positions=None, max_iters=12, weight_exp=-2, is_stopped=lambda : ..., preview_available=lambda x, y: ..., layout_available=lambda x, y: ..., layout_progressed=lambda iter: ...)[source]

A class to build an optimised layout for an undirected graph. This can help visualizing the Spine data structure of multi-dimensional entities.

Parameters:

  • vertex_count (int) – The number of vertices in the graph. Graph vertices will have indices 0, 1, 2, …

  • src_inds (tuple, optional) – The indices of the source vertices of each edge.

  • dst_inds (tuple, optional) – The indices of the destination vertices of each edge.

  • spread (int, optional) – the ideal edge length.

  • heavy_positions (dict, optional) – a dictionary mapping vertex indices to another dictionary with keys “x” and “y” specifying the position it should have in the generated layout.

  • max_iters (int, optional) – the maximum numbers of iterations of the layout generation algorithm.

  • weight_exp (int, optional) – The exponential decay rate of attraction between vertices. The higher this number, the lesser the attraction between distant vertices.

  • is_stopped (function, optional) – A function to call without arguments, that returns a boolean indicating whether the layout generation process needs to be stopped.

  • preview_available (function, optional) – A function to call after every iteration with two lists, x and y, representing the current layout.

  • layout_available (function, optional) – A function to call after the last iteration with two lists, x and y, representing the final layout.

  • layout_progressed (function, optional) – A function to call after each iteration with the current iteration number.

compute_layout()[source]

Computes the layout using VSGD-MS and returns x and y coordinates for each vertex in the graph.

Returns:

x and y coordinates

Return type:

tuple(list,list)