# spd2rc: Computes rates of change from SPDs In rcarbon: Calibration and Analysis of Radiocarbon Dates

## Description

Function for computing rates of change between abutting user-defined time-blocks.

## Usage

 ```1 2 3 4 5 6``` ```spd2rc( spd, breaks = NULL, backsight = NULL, changexpr = expression((t1/t0)^(1/d) - 1) ) ```

## Arguments

 `spd` Summed Probability Distribution obtained using the `spd` function. `breaks` A vector giving the breakpoints between the time-blocks. `backsight` A single numeric value defining the distance in time between the focal year and the backsight year for computing the rate of change. `changexpr` An expression defining how the rate of change is calculated, where `t1` is the summed probability for a focal block or year, `t0` is the summed probability for previous block or backsight year, and `d` is the duration of the block or the length of the backsight. Default is a geometric growth rate (i.e `expression((t1/t0)^(1/d)-1)`).

## Details

When the argument `breaks` is supplied the function aggregates the summed probability within each time-block and compared them across abutting blocks using the expression defined by `changexpr`. When the argument `backsight` is provided he expression is based on the comparison between the summed probability of each year and the associated backsight year.

## Value

An object of class `spdRC`.

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11``` ```## Not run: data(emedyd) caldates <- calibrate(x=emedyd\$CRA, errors=emedyd\$Error, normalised=FALSE, calMatrix=TRUE) bins <- binPrep(sites=emedyd\$SiteName, ages=emedyd\$CRA, h=50) emedyd.spd <- spd(caldates,bins,timeRange=c(16000,9000),runm=100) emedyd.gg <- spd2rc(emedyd.spd,breaks=seq(16000,9000,-1000)) emedyd.gg2 <- spd2rc(emedyd.spd,backsight=10) plot(emedyd.gg) plot(emedyd.gg2) ## End(Not run) ```

rcarbon documentation built on Jan. 13, 2021, 7:09 p.m.