creategroups {biotools} | R Documentation |

## Creating Homogeneous Groups

### Description

A function to create homogeneous groups of named objects according to an objective function evaluated at a covariate. It can be useful to design experiments which contain a fixed covariate factor.

### Usage

```
creategroups(x, ngroups, sizes, fun = mean, tol = 0.01, maxit = 200)
```

### Arguments

`x` |
a numeric vector of a covariate at which to evaluate the objective function. |

`ngroups` |
the number of groups to create. |

`sizes` |
a numeric vector of length equal to |

`fun` |
the objective function, i.e., to create groups with similar |

`tol` |
the tolerance level to define the groups as homogenenous; see details. |

`maxit` |
the maximum number of iterations; default is 200. |

### Details

`creategroups`

uses a `tol`

value to evaluate the following statistic:
`h = \sum_{j}^{ngroups} abs( t_{j+1} - t_j ) / ngroups`

, where `t_j = fun(group_j)`

.
If `h \leq tol`

, the groups are considered homogeneous.

### Value

A list of

`covar` |
a character indicating the name of the covariate. |

`func` |
a character indicating the name of the objective function. |

`val.func` |
a numeric vector containing the values evaluated by |

`niter` |
the number of iteration require to achieve convergence. |

`labels` |
a list containing the labels of the objects in each group. |

`groups` |
a list of named vectors containing the values for the groups |

### Author(s)

Anderson Rodrigo da Silva <anderson.agro@hotmail.com>

### Examples

```
x <- rnorm(10, 1, 0.5)
names(x) <- letters[1:10]
creategroups(x, ngroups = 2, sizes = c(5, 5))
creategroups(x, ngroups = 3, sizes = c(3, 4, 3), tol = 0.05)
# End (not run)
```

*biotools*version 4.2 Index]