How to specify dashed edges in SageMath?

asked 2024-03-18 10:29:23 +0100

licheng gravatar image

updated 2024-10-15 05:38:19 +0100

I would like to present some subgraphs of a graph. Considering that the printed version is in black and white, I would like the highlighted subgraphs to appear as red dashed lines. However, I have only seen settings for color. I am not sure how to set the dashed lines.

g=Graph([(0, 1), (0, 3), (0, 4), (0, 5), (0, 6), (0, 7), (0, 8), (1, 3), (1, 5), (1, 7), (1, 8), (1, 9), (1, 10), 
       (3, 4), (3, 5), (3, 10), (4, 5), (5, 6), (5, 7), (5, 9), (5, 10), (6, 7), (7, 8), (7, 9)])
g.plot(layout="planar",save_pos=True)
s=g.hamiltonian_cycle()
s1=s.edges(labels=False)
#print(s1)
def plot_with_highlight(G, highlight_edges):
    highlight_vertices = list(set().union(*highlight_edges))
    G.plot(edge_colors={'red': highlight_edges}, vertex_colors={'red': highlight_vertices}).show()
plot_with_highlight(g,s1)

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Comments

Have look here https://ask.sagemath.org/question/35638/drawing-auslander-reiten-quivers-with-sage-possible/. I rember also that you can force the vertices to a desired locations. In such a way an edge could not intersect or recover a vertex

Cyrille gravatar imageCyrille ( 2024-03-18 15:14:05 +0100 )edit

Great, but it feels like this method isn't a modification, but rather a reconstruction of the plot.

licheng gravatar imagelicheng ( 2024-03-19 01:46:46 +0100 )edit

As shown in the documentation of g.plot, you may use edge_style='dashed'. But unfortunately, it plots every edge to be dashed.

A contribution is more than welcome to make this argument take a dictionnary as input like for edge_colors input.

Sébastien gravatar imageSébastien ( 2024-10-15 12:21:47 +0100 )edit
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