# curve_multiple

From igraph v1.0.0
by Gabor Csardi

##### Optimal edge curvature when plotting graphs

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.

- Keywords
- graphs

##### Usage

`curve_multiple(graph, start = 0.5)`

##### Arguments

- graph
- The input graph.
- start
- The curvature at the two extreme edges. All edges will have a
curvature between
`-start`

and`start`

, spaced equally.

##### Details

`curve_multiple`

calculates the optimal `edge.curved`

vector for
plotting a graph with multiple edges, so that all edges are visible.

##### Value

- A numeric vector, its length is the number of edges in the graph.

##### See Also

`igraph.plotting`

for all plotting parameters,
`plot.igraph`

, `tkplot`

and `rglplot`

for plotting functions.

##### Examples

```
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)
set.seed(42)
plot(g)
```

*Documentation reproduced from package igraph, version 1.0.0, License: GPL (>= 2)*

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