ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 28 Nov 2022 15:45:48 +0100Can't use Edmonds_karp algorithm to find maximum flowhttps://ask.sagemath.org/question/65099/cant-use-edmonds_karp-algorithm-to-find-maximum-flow/Hello, I am new to Sagemath i wanted to use the algorithm of Edmonds_Karp to find maximum flow, but it seems that only Ford_Fulkerson is available in the documentation thought I found a file named Edmonds_karp in the files of sagemath, I can't seem to make it work with the source code. I wanted to know if someone has a way to use the algorithm or could tell me what i should do to make the source code work ?
colapstarMon, 28 Nov 2022 15:45:48 +0100https://ask.sagemath.org/question/65099/flow control in sage notebooks?https://ask.sagemath.org/question/46163/flow-control-in-sage-notebooks/ I would love to insert a *break* or *stop* command into sage files, in order to absolutly stop further processing. The interpreter (?) should not die or exit, but rather pretent to be done with the notebook.
I looked through the sage reference and didnt find something similar. actually i didnt find anything on the whole flow control topic. stockh0lmSun, 14 Apr 2019 21:00:24 +0200https://ask.sagemath.org/question/46163/Flow gives error for disconnected verticeshttps://ask.sagemath.org/question/41419/flow-gives-error-for-disconnected-vertices/ When calculating the flow between to vertices which are not connected in a graph, the method returns a ValueError. I would have assumed that it would just return 0. Here's a minimal example:
G=Graph({0:[],1:[]})
G.flow(0,1) # raises the error ValueError: vertex '0' is not in the (di)graph
If on the other hand one tries the shortest_path method it just returns a empty list, since there is not path between 0 and 1.
G.shortest_path(0,1) #returns []AckslWed, 07 Mar 2018 13:21:06 +0100https://ask.sagemath.org/question/41419/edge labels and vertex size causes problemshttps://ask.sagemath.org/question/10776/edge-labels-and-vertex-size-causes-problems/Hi,
I have several problems creating a graph. I want to misuse the graph tools in sagemath to create a flow diagram, but I encountered two problems:
First, the vertex_size option does not work at all in my code and
second, relating to the question
[here](http://ask.sagemath.org/question/1700/getting-edge-labels-in-a-digraph-to-display), is there now a possibility to shift the edge labels?
I work with sage 5.9 in a virtual box environment
from sage.graphs.graph_plot import GraphPlot
h = DiGraph({0:[1,2], 1:[3], 2:[4]})
for u,v,l in h.edges():
h.set_edge_label(u,v,'(' + str(u) + ',' + str(v) + ')')
h1=h.graphplot(save_pos=True, edge_labels=True, talk=True)
h1.show()
print h.get_pos()
h.set_pos({0:[0,0],1:[1,1],2:[1,-1],3:[2,1],4:[3,-1]})
h1=h.graphplot(save_pos=True, edge_labels=True, talk=True, vertex_size=0)
h1.set_vertices(vertex_shape='s')
h1.show()
Thanks in advance.god.oneTue, 26 Nov 2013 04:33:26 +0100https://ask.sagemath.org/question/10776/