# double arrow in GraphPlot

Is it possible to combine two edges into one with a double arrow?

For example:

GraphPlot[{1 -> 2, 2 -> 1}, VertexLabeling -> True,
DirectedEdges -> True]


results something like

Is it possible to change it to something like

without using the drawing tool to edit the graphics directly?

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Which version of Mathematica are you using? – Szabolcs Apr 20 '13 at 19:02
version 8 on Mac. – user0501 Apr 20 '13 at 19:05

This is a hack, but it'll work with GraphPlot:
GraphPlot[{1 -> 2, 2 -> 1, 1 -> 3, 3 -> 2}, MultiedgeStyle -> .001,

@user0501 Unfortunately no. I'd have to search the docs more for that and right now I do not have the time. Also, ideally there should be a solution for Graph objects, not just GraphPlot. My answer is by no means complete. – Szabolcs Apr 20 '13 at 19:35
@user0501 I'm trying to do the same thing with LayeredGraphPlot with little success, so I might try Szabolcs solution. However, from your comment, to deal with the thicker double arrow, could you add something in such that if a rule and its inverse are both found, to reduce the thickness of each resulting edge by 50%? – iwantmyphd Jun 12 '15 at 19:47