1.6. igraph_layout_kamada_kawai — Places the vertices on a plane according the Kamada-Kawai algorithm.

1.6. `igraph_layout_kamada_kawai` — Places the vertices on a plane according the Kamada-Kawai algorithm.

int igraph_layout_kamada_kawai(const igraph_t *graph, igraph_matrix_t *res,
			       igraph_integer_t niter, igraph_real_t sigma, 
			       igraph_real_t initemp, igraph_real_t coolexp,
			       igraph_real_t kkconst, igraph_bool_t use_seed);

This is a force directed layout, see Kamada, T. and Kawai, S.: An Algorithm for Drawing General Undirected Graphs. Information Processing Letters, 31/1, 7--15, 1989. This function was ported from the SNA R package.

Arguments:

`graph`:	A graph object.
`res`:	Pointer to an initialized matrix object. This will contain the result and will be resized if needed.
`niter`:	The number of iterations to perform.
`sigma`:	Sets the base standard deviation of position change proposals.
`initemp`:	Sets the initial temperature for the annealing.
`coolexp`:	The cooling exponent of the annealing.
`kkconst`:	The Kamada-Kawai vertex attraction constant.
`use_seed`:	Boolean, whether to use the values cupplied in the `res` argument as the initial configuration. If zero then a random initial configuration is used.

Returns:

Error code.

Time complexity: O(|V|^2) for each iteration, |V| is the number of vertices in the graph.