Graph options¶
Directed graphs¶
Directed graphs can be obtained by using the directed parameter in the graph constructor.
If this parameter is None, an undirected graph will be produced.
Otherwise, for a directed graph, directed can take one of the following values:
left_to_right:Edge directions go from left to right according to the series temporal x axis.
top_to_bottom:Edge directions go from top to bottom according to the series y axis.
Note
If both endpoints of an edge have the exact same y value then the direction is ambiguous and no consistent direction is guaranteed.
Weighted graphs¶
Weighted graphs can be obtained by using the weighted parameter in the graph constructor.
If this parameter is None, an unweighted graph will be produced.
Otherwise, for a weighted graph, weighted can take one of the following values
(assuming directed edges going from point \((x_i, y_i)\) to point \((x_j, y_j)\)):
distance:Euclidean distance. Calculated as:
\[\sqrt{(x_j - x_i)^2 \cdot (y_j - y_i)^2}\]sq_distance:Squared Euclidean distance (quicker to compute than regular Euclidean distance). Calculated as:
\[(x_j - x_i)^2 \cdot (y_j - y_i)^2\]v_distance:Vertical distance. Calculated as:
\[y_j - y_i\]abs_v_distance:Absolute vertical distance. Calculated as:
\[\left| y_j - y_i \right|\]h_distance:Horizontal distance. Calculated as:
\[x_j - x_i\]abs_h_distance:Absolute horizontal distance. Calculated as:
\[\left| x_j - x_i \right|\]slope:Slope, in the range (-∞, +∞). Calculated as:
\[\frac{y_j - y_i}{x_j - x_i}\]abs_slope:Absolute slope, in the range (0, +∞). Calculated as:
\[\left| \frac{y_j - y_i}{x_j - x_i} \right|\]angle:Slope angle in radians, in the range (-π/2, +π/2). Calculated as:
\[\arctan \left( \frac{y_j - y_i}{x_j - x_i} \right)\]abs_angle:Absolute slope angle in radians, in the range (0, +π/2). Calculated as:
\[\arctan \left( \left| \frac{y_j - y_i}{x_j - x_i} \right| \right)\]num_penetrations:In limited penetrable visibility graphs this is the number of obstructing intermediate data points that the edge is penetrating. In non-penetrable (the default) visibility graphs this is always 0 by definition.
Note
Asymmetrical weight functions (like v_distance, h_distance, slope, angle) depend on the edge direction,
the direction specified in the directed parameter is used.
If the graph is undirected, a ‘left to right’ edge direction is used by default.