# Calculate proportionality metric rho.

### Description

`perb`

returns a `propr`

object containing a measure of proportionality.

### Usage

1 | ```
perb(counts, ivar = 0, select)
``` |

### Arguments

`counts` |
A data.frame or matrix. A "count matrix" with subjects as rows and features as columns. |

`ivar` |
A numeric scalar. Specificies a reference feature for additive log-ratio transformation. Argument will now accept the feature name instead of index. |

`select` |
Subsets via |

### Details

Let d represent any number of features measured across n biological replicates subjected to a binary or continuous event E. For example, E could represent case-control status, treatment status, treatment dose, or time. This function converts a "count matrix" with n rows and d columns into a proportionality matrix of d rows and d columns containing rho measurements for each feature pair. One can think of the resultant matrix as equivalent to a correlation matrix.

This function uses a centered log-ratio transformation of the data by default,
but will use an additive log-ratio transformation of the data if a non-zero
`ivar`

is provided. When using an additive log-ratio transformation,
this function will return `rho = 0`

for each pair containing the
reference feature.

### Value

Returns a `propr`

object.

### See Also

`propr`

, `propr-class`

, `phit`

### Examples

1 2 3 |