These functions implement evolving network models based on different vertex types.

## Arguments

- nodes
The number of vertices in the graph.

- types
The number of different vertex types.

- edge.per.step
The number of edges to add to the graph per time step.

- type.dist
The distribution of the vertex types. This is assumed to be stationary in time.

- pref.matrix
A matrix giving the preferences of the given vertex types. These should be probabilities, i.e. numbers between zero and one.

- directed
Logical constant, whether to generate directed graphs.

- ...
Passed to the constructor,

`sample_traits()`

or`sample_traits_callaway()`

.- k
The number of trials per time step, see details below.

## Details

For `sample_traits_callaway()`

the simulation goes like this: in each
discrete time step a new vertex is added to the graph. The type of this
vertex is generated based on `type.dist`

. Then two vertices are
selected uniformly randomly from the graph. The probability that they will
be connected depends on the types of these vertices and is taken from
`pref.matrix`

. Then another two vertices are selected and this is
repeated `edges.per.step`

times in each time step.

For `sample_traits()`

the simulation goes like this: a single vertex is
added at each time step. This new vertex tries to connect to `k`

vertices in the graph. The probability that such a connection is realized
depends on the types of the vertices involved and is taken from
`pref.matrix`

.

## See also

Random graph models (games)
`erdos.renyi.game()`

,
`sample_()`

,
`sample_bipartite()`

,
`sample_correlated_gnp()`

,
`sample_correlated_gnp_pair()`

,
`sample_degseq()`

,
`sample_dot_product()`

,
`sample_fitness()`

,
`sample_fitness_pl()`

,
`sample_forestfire()`

,
`sample_gnm()`

,
`sample_gnp()`

,
`sample_grg()`

,
`sample_growing()`

,
`sample_hierarchical_sbm()`

,
`sample_islands()`

,
`sample_k_regular()`

,
`sample_last_cit()`

,
`sample_pa()`

,
`sample_pa_age()`

,
`sample_pref()`

,
`sample_sbm()`

,
`sample_smallworld()`

,
`sample_tree()`

## Author

Gabor Csardi csardi.gabor@gmail.com