kairos (version 2.2.0)

apportion: Chronological Apportioning

Description

Chronological Apportioning

Usage

apportion(object, ...)
# S4 method for data.frame
apportion(
  object,
  s0,
  s1,
  t0,
  t1,
  from = min(s0),
  to = max(s1),
  step = 25,
  method = c("uniform", "truncated"),
  z = 2,
  progress = getOption("kairos.progress")
)
# S4 method for matrix
apportion(
  object,
  s0,
  s1,
  t0,
  t1,
  from = min(s0),
  to = max(s1),
  step = 25,
  method = c("uniform", "truncated"),
  z = 2,
  progress = getOption("kairos.progress")
)

Value

A CountApportion object.

Arguments

object

A \(m \times p\) numeric matrix or data.frame of count data (absolute frequencies giving the number of individuals for each category, i.e. a contingency table). A data.frame will be coerced to a numeric matrix via data.matrix().

...

Currently not used.

s0

A length-\(m\) numeric vector giving the site beginning dates expressed in CE years (BCE years must be given as negative numbers).

s1

A length-\(m\) numeric vector giving the site end dates expressed in CE years (BCE years must be given as negative numbers).

t0

A length-\(p\) numeric vector giving the type beginning dates expressed in CE years (BCE years must be given as negative numbers).

t1

A length-\(p\) numeric vector giving the type end dates expressed in CE years (BCE years must be given as negative numbers).

from

A length-one numeric vector giving the beginning of the period of interest (in years CE).

to

A length-one numeric vector giving the end of the period of interest (in years CE).

step

A length-one integer vector giving the step size, i.e. the width of each time step for apportioning (in years CE; defaults to \(25\)).

method

A character string specifying the distribution to be used (type popularity curve). It must be one of "uniform" (uniform distribution) or "truncated" (truncated standard normal distribution). Any unambiguous substring can be given.

z

An integer value giving the lower and upper truncation points (defaults to \(2\)). Only used if method is "truncated".

progress

A logical scalar: should a progress bar be displayed?

Author

N. Frerebeau

References

Roberts, J. M., Mills, B. J., Clark, J. J., Haas, W. R., Huntley, D. L. & Trowbridge, M. A. (2012). A Method for Chronological Apportioning of Ceramic Assemblages. Journal of Archaeological Science, 39(5): 1513-20. tools:::Rd_expr_doi("10.1016/j.jas.2011.12.022").

See Also

Other chronological analysis: fit(), plot_fit

Examples

## Replication of Roberts et al. 2012
bayless <- matrix(
  data = c(4, 333, 11, 11, 13, 1605, 252, 9, 48), nrow = 1,
  dimnames = list(c("Bayless"), c("CWW", "CBW", "LMGRW", "LTB", "MMS",
                                  "PBW", "RRW", "SCBW", "TBBW"))
)

## Set ware start and end dates
start <- c(550, 800, 1200, 1150, 1275, 200, 1275, 1200, 750)
end <- c(1325, 1400, 1450, 1300, 1400, 1450, 1450, 1450, 1300)

## Apportion ceramic assemblage under flat/uniform distribution
app <- apportion(bayless, s0 = 1200, s1 = 1350, t0 = start, t1 = end,
                 step = 50, method = "uniform")

## Apportion ceramic assemblage under truncated standard normal distribution
app <- apportion(bayless, s0 = 1200, s1 = 1350, t0 = start, t1 = end,
                 step = 50, method = "truncated", z = 2)

## Array of results
head(app)