Use this if you are using igraph from R
| curve_multiple {igraph} | R Documentation | 
If graphs have multiple edges, then drawing them as straight lines does not show them when plotting the graphs; they will be on top of each other. One solution is to bend the edges, with diffenent curvature, so that all of them are visible.
curve_multiple(graph, start = 0.5)
| graph | The input graph. | 
| start | The curvature at the two extreme edges. All edges will have a
curvature between  | 
curve_multiple calculates the optimal edge.curved vector for
plotting a graph with multiple edges, so that all edges are visible.
A numeric vector, its length is the number of edges in the graph.
Gabor Csardi csardi.gabor@gmail.com
igraph.plotting for all plotting parameters,
plot.igraph, tkplot and rglplot
for plotting functions.
g <- graph( c(0,1,1,0,1,2,1,3,1,3,1,3,
              2,3,2,3,2,3,2,3,0,1)+1 )
curve_multiple(g)
## Not run: 
set.seed(42)
plot(g)
## End(Not run)