# Import MCMC Samples

#### A. Philippe, M.-A. Vibet and N. Frerebeau

#### 2025-09-22

This vignette uses data available through the ArchaeoData package which is available in a separate repository. ArchaeoData provides MCMC outputs from ChronoModel, OxCal and BCal.

    ## Install data package
    install.packages("ArchaeoData", repos = "https://archaeostat.r-universe.dev")

    ## Load package
    library(ArchaeoPhases)

# 1 ChronoModel

Two different files are generated by ChronoModel: `Chain_all_Events.csv` that contains the MCMC samples of each event created in the modeling, and `Chain_all_Phases.csv` that contains all the MCMC samples of the minimum and the maximum of each group of dates if at least one group is created.

    ## Construct the path to the data
    path_events <- file.path("chronomodel", "ksarakil", "Chain_all_Events.csv")
    output_events <- system.file(path_events, package = "ArchaeoData")

    ## Read events from ChronoModel
    chrono_events <- read_chronomodel_events(output_events)

    ## Plot events
    plot(chrono_events)

plot of chunk read-chronomodel-events

    ## Construct the path to the data
    path_phases <- file.path("chronomodel", "ksarakil", "Chain_all_Phases.csv")
    output_phases <- system.file(path_phases, package = "ArchaeoData")

    ## Read phases from ChronoModel
    chrono_phases <- read_chronomodel_phases(output_phases)

    ## Plot phases
    plot(chrono_phases)

plot of chunk read-chronomodel-phases

# 2 Oxcal

Oxcal generates a CSV file containing the MCMC samples of all parameters (dates, start and end of phases).

    ## Construct the path to the data
    path_oxcal <- file.path("oxcal", "ksarakil", "MCMC_Sample.csv")
    output_oxcal <- system.file(path_oxcal, package = "ArchaeoData")

    ## Read OxCal MCMC samples
    oxcal_mcmc <- read_oxcal(output_oxcal)

    ## Plot events
    plot(oxcal_mcmc)

plot of chunk read-oxcal

The phase boundaries cannot be extracted automatically from Oxcal output. Use `as_phases()` to get the phase boundaries:

    ## Get phases boundaries from OxCal
    oxcal_phases <- phases(
      x = oxcal_mcmc,
      groups = list(IUP = c(2, 4), Ahmarian = c(5, 18),
                    UP = c(19, 23), EPI = c(24, 26))
    )

    ## Plot phase boundaries
    plot(oxcal_phases)

plot of chunk oxcal-phases

# 3 BCal

BCal generates a CSV file containing the MCMC samples of all parameters (dates, start and end of groups).

    ## Construct the path to the data
    path_bcal <- file.path("bcal", "fishpond.csv")
    output_bcal <- system.file(path_bcal, package = "ArchaeoData")

    ## Read BCal MCMC samples
    bcal_mcmc <- read_bcal(output_bcal)

The group boundaries cannot be extracted automatically from BCal output. Use `as_phases()` to get the group boundaries:

    ## Get groups boundaries from BCal
    bcal_phases <- phases(
      x = bcal_mcmc,
      groups = list(`Layer II` = c(6, 1), `Layer III` = c(9, 7))
    )

    ## Plot group boundaries
    plot(bcal_phases)

plot of chunk bcal-phases