# GrowthRates: Calculates growth rates (AGR, PGR, RGRdiff) between pairs of... In growthPheno: Functional Analysis of Phenotypic Growth Data to Smooth and Extract Traits

 GrowthRates R Documentation

## Calculates growth rates (AGR, PGR, RGRdiff) between pairs of values in a vector

### Description

Calculates either the Absolute Growth Rate (AGR), Proportionate Growth Rate (PGR) or Relative Growth Rate (RGR) between pairs of time points, the second of which is `lag` positions before the first. in `x`.

### Usage

``````AGRdiff(x, time.diffs, lag=1)
PGR(x, time.diffs, lag=1)
RGRdiff(x, time.diffs, lag=1)``````

### Arguments

 `x` A `numeric` from which the growth rates are to be calculated. `time.diffs` a `numeric` giving the time differences between successive values in `x`. `lag` A `integer` specifying, for the second value in the pair to be operated on, the number positions it is ahead of the current value.

### Details

The AGRdiff is calculated as the difference between a pair of values divided by the `time.diffs`. The PGR is calculated as the ratio of a value to a second value which is `lag` values ahead of the first in `x` and the ratio raised to the power of the reciprocal of `time.diffs`. The RGRdiff is calculated as the `log` of the PGR and so is equal to the difference between the logarithms of a pair of values divided by the `time.diffs`. The differences and ratios are obtained using `calcLagged` with `lag = 1`.

### Value

A `numeric` containing the growth rates which is the same length as `x` and in which the first `lag` values `NA`.

### Author(s)

Chris Brien

`byIndv4Intvl_GRsAvg`, `byIndv4Intvl_GRsDiff`, `byIndv4Times_GRsDiff`, `byIndv4Times_SplinesGRs`,
`calcLagged`
``````data(exampleData)