Subset counts so that all samples have the same number of observations.

rarefy(biom, depth = NULL, seed = 0)

## Arguments

biom |
A `matrix` , `simple_triplet_matrix` , or `BIOM`
object, as returned from read.biom. For matrices, the rows and
columns are assumed to be the taxa and samples, respectively. |

depth |
The number of observations to keep, per sample. If set to
`NULL` , a depth will be automatically selected. Samples that have
fewer than this number of observations will be dropped. If called on
data with non-integer abundances, values will be re-scaled to integers
between 1 and `depth` such that they sum to `depth` . |

seed |
An integer to use for seeding the random number generator. If
you need to create different random rarefactions of the same `BIOM`
object, set this seed value to a different number each time. |

## Value

A `matrix`

, `simple_triplet_matrix`

, or `BIOM`

object, depending on the input object type. The type of object provided
is the same type that is returned. The retained observations are randomly
selected, based on a seed value derived from the `BIOM`

object.
Therefore, rarefying the same biom to the same depth will always produce
the same resultant rarification.

## Examples

#> [1] 182 22117

#> [1] 1000 1000