# Generate a random bipartite web

### Description

Generates a random bipartite web, based on `r2dtable`

and lognormal marginal distributions.

### Usage

1 | ```
genweb(N1 = 10, N2 = 30, dens = 2)
``` |

### Arguments

`N1` |
Number of species in the lower trophic level; or a vector of length 2 giving number of lower and higher trophic level species. Defaults to 10. Large values (>70) will take much longer! |

`N2` |
Number of species in the higher trophic level. Ignored if N1 a vector of length 2. Defaults to 30. Large values (>70) will take much longer! |

`dens` |
Interaction density, i.e. how many interactions there shall be, on average, for each |

### Details

This function can be used to create simple, but not necessarily realistic, bipartite webs for given dimensionality and interaction density. Marginal distributions are assumed to be lognormal, mean and standard deviation are calculated from N1, N2 and dens (see code for details).

### Value

A matrix with N1 x N2 species.

### Note

Can be a bit time-consuming for large webs, because the absolute values for both dimensions have to match perfectly. This involves a rather inelegant `while`

-loop.

### Author(s)

Jochen Fründ and Carsten F. Dormann

### Examples

1 | ```
genweb()
``` |