`vignettes/BayLum.Rmd`

`BayLum.Rmd`

`'BayLum'`

provides a collection of various
**R** functions for Bayesian analysis of luminescence data.
Amongst others, this includes data import, export, application of age
models and palaeodose modelling.

Data can be processed simultaneously for various samples, including the input of multiple BIN/BINX-files per sample for single grain (SG) or multi-grain (MG) OSL measurements. Stratigraphic constraints and systematic errors can be added to constrain the analysis further.

For those who already know how to use **R**,
`'BayLum'`

won’t be difficult to use, for all others, this
brief introduction may be of help to make the first steps with
**R** and the package `'BayLum'`

as convenient
as possible.

If you read this document before having installed **R**
itself, you should first visit the R
project website and download and install **R**. You may
also consider installing Rstudio, which
provides an excellent desktop working environment for
**R**; however it is not a prerequisite.

You will also need the external software *JAGS* (Just Another
Gibs Sampler). Please visit the JAGS webpage and follow the
installation instructions. Now you are nearly ready to work with
‘BayLum’.

If you have not yet installed ‘BayLum’, please run the following two
**R** code lines to install ‘BayLum’ on your computer.

```
if(!require("BayLum"))
install.packages("BayLum", dependencies = TRUE)
```

Alternatively, you can load an already installed **R**
package (here ‘BayLum’) into your session by using the following
**R** call.

Measurement data can be imported using two different options as detailed in the following:

- Option 1: Using the conventional ‘BayLum’ folder structure (old)
- Option 2: Using a single-setting config file (new)

Let us consider the sample named *samp1*, which is the example
dataset coming with the package. All information related to this sample
is stored in a subfolder called also *samp1*. To test the package
example, first, we add the path of the example dataset to the object
`path`

.

`path <- paste0(system.file("extdata/", package = "BayLum"), "/")`

Please note that for your own dataset (i.e. not included in the package) you have to replace this call by something like:

`path <- "Users/Master_of_luminescence/Documents/MyFamousOSLData"`

In our example the folder contains the following subfolders and files:

1 | example.yml |

2 | FER1/bin.bin |

3 | FER1/Disc.csv |

4 | FER1/DoseEnv.csv |

5 | FER1/DoseSource.csv |

6 | FER1/rule.csv |

7 | samp1/bin.bin |

8 | samp1/DiscPos.csv |

9 | samp1/DoseEnv.csv |

10 | samp1/DoseSource.csv |

11 | samp1/rule.csv |

12 | samp2/bin.bin |

13 | samp2/DiscPos.csv |

14 | samp2/DoseEnv.csv |

15 | samp2/DoseSource.csv |

16 | samp2/rule.csv |

17 | yaml_config_reference.yml |

See *“What are the required files in each subfolder?”* in the
manual of `Generate_DataFile()`

function for the meaning of
these files.

To import your data, simply call the function
`Generate_DataFile()`

:

```
DATA1 <-
Generate_DataFile(
Path = path,
FolderNames = "samp1",
Nb_sample = 1,
verbose = FALSE)
```

```
Warning in Generate_DataFile(Path = path, FolderNames = "samp1", Nb_sample = 1, : 'Generate_DataFile' is deprecated.
Use 'create_DataFile()' instead.
See help("Deprecated")
```

The import may take a while, in particular for large BIN/BINX-files. This can become annoying if you want to play with the data. In such situations, it makes sense to save your imported data somewhere else before continuing.

To save the obove imported data on your hardrive use

`save(DATA1, file = "YourPath/DATA1.RData")`

To load the data use

`load(DATA1, file = "YourPath/DATA1.RData")`

To see the overall structure of the data generated from the BIN/BINX-file and the associated CSV-files, the following call can be used:

`str(DATA1)`

```
List of 9
$ LT :List of 1
..$ : num [1, 1:7] 2.042 0.842 1.678 3.826 4.258 ...
$ sLT :List of 1
..$ : num [1, 1:7] 0.344 0.162 0.328 0.803 0.941 ...
$ ITimes :List of 1
..$ : num [1, 1:6] 15 30 60 100 0 15
$ dLab : num [1:2, 1] 1.53e-01 5.89e-05
$ ddot_env : num [1:2, 1] 2.512 0.0563
$ regDose :List of 1
..$ : num [1, 1:6] 2.3 4.6 9.21 15.35 0 ...
$ J : num 1
$ K : num 6
$ Nb_measurement: num 16
```

It reveals that `DATA1`

is basically a list with 9
elements:

Element | Content |
---|---|

`DATA1$LT` |
\(L_x\)/\(T_x\) values from each sample |

`DATA1$sLT` |
\(L_x\)/\(T_x\) error values from each sample |

`DATA1$ITimes` |
Irradiation times |

`DATA1$dLab` |
The lab dose rate |

`DATA1$ddot_env` |
The environmental dose rate and its variance |

`DATA1$regDose` |
The regenerated dose points |

`DATA1$J` |
The number of aliquots selected for each BIN-file |

`DATA1$K` |
The number of regenerated dose points |

`DATA1$Nb_measurement` |
The number of measurements per BIN-file |

To get an impression on how your data look like, you can visualise
them by using the function `LT_RegenDose()`

:

```
LT_RegenDose(
DATA = DATA1,
Path = path,
FolderNames = "samp1",
SampleNames = "samp1",
Nb_sample = 1,
nrow = NULL
)
```

```
Warning in LT_RegenDose(DATA = DATA1, Path = path, FolderNames = "samp1", : 'LT_RegenDose' is deprecated.
Use 'plot_RegDosePoints()' instead.
See help("Deprecated")
```

Note that here we consider only one sample, and the name of the
folder is the name of the sample. For that reason the argumetns were set
to `FolderNames = samp1`

and
`SampleNames = samp1`

.

For a multi-grain OSL measurements, instead of
`Generate_DataFile()`

, the function
`Generate_DataFile_MG()`

should be used with similar
parameters. The functions differ by their expectations:
*Disc.csv* instead of *DiscPos.csv* file for Single-grain
OSL Measurements. Please check type `?Generate_DataFile_MG`

for further information.

`create_DataFile()`

With `'BayLum'`

>= v0.3.2 we introduced a new function
called `create_DataFile()`

, which will at some point in time
replace the function `Generate_DataFile()`

and
`Generate_DataFile_MG()`

. `create_DataFile()`

works conceptionally very different from the approach detailed above.
Key differences are:

- The function uses a single configuration file for all samples and all measurement files
- The very error prone subfolder structure is no longer needed
- Measurement data can be imported with
`create_DataFile()`

, but also outside of the function and then passed on the functions. This enables the possibility of extensive pre-processing and selection of measurement data.

The configuration follows the so-called YAML format specification. For single sample the file looks as follows:

```
- sample: "samp1"
files: null
settings:
dose_source: { value: 0.1535, error: 0.00005891 }
dose_env: { value: 2.512, error: 0.05626 }
rules:
beginSignal: 6
endSignal: 8
beginBackground: 50
endBackground: 55
beginTest: 6
endTest: 8
beginTestBackground: 50
endTestBackground: 55
inflatePercent: 0.027
nbOfLastCycleToRemove: 1
```

In the case above, the configuration file assumes that data for
`samp1`

are already imported and treated and a R object
called `samp1`

is available in the global environment. The
following example code reproduces this case:

```
## get example file path from package
yaml_file <- system.file("extdata/example.yml", package = "BayLum")
samp1_file <- system.file("extdata/samp1/bin.bin", package = "BayLum")
## read YAML manually and select only the first record
config_file <- yaml::read_yaml(yaml_file)[[1]]
## import BIN/BINX files and select position 2 and grain 32 only
samp1 <- Luminescence::read_BIN2R(samp1_file, verbose = FALSE) |>
subset(POSITION == 2 & GRAIN == 32)
## create the data file
DATA1 <- create_DataFile(config_file, verbose = FALSE)
```

To compute the age of the sample *samp1*, you can run the
following code:

```
Age <- Age_Computation(
DATA = DATA1,
SampleName = "samp1",
PriorAge = c(10, 100),
distribution = "cauchy",
LIN_fit = TRUE,
Origin_fit = FALSE,
Iter = 10000
)
```

```
Compiling model graph
Resolving undeclared variables
Allocating nodes
Graph information:
Observed stochastic nodes: 6
Unobserved stochastic nodes: 9
Total graph size: 139
Initializing model
```

```
>> Sample name <<
----------------------------------------------
samp1
>> Results of the Gelman and Rubin criterion of convergence <<
----------------------------------------------
Point estimate Uppers confidence interval
A 1.016 1.04
D 1.015 1.038
sD 1.181 1.266
---------------------------------------------------------------------------------------------------
*** WARNING: The following information are only valid if the MCMC chains have converged ***
---------------------------------------------------------------------------------------------------
parameter Bayes estimate Credible interval
----------------------------------------------
A 27.598
lower bound upper bound
at level 95% 10 81.783
at level 68% 10 28.852
----------------------------------------------
D 68.636
lower bound upper bound
at level 95% 19.327 202.298
at level 68% 21.336 73.265
----------------------------------------------
sD 49.155
lower bound upper bound
at level 95% 0.529 156.114
at level 68% 0.48 34.838
```

This also works if `DATA1`

is the output of
`Generate_DataFile_MG()`

.

If MCMC trajectories did not converge, you can add more iteration with the parameter

`Iter`

in the function`Age_Computation()`

, for example`Iter = 20000`

or`Iter = 50000`

. If it is not desirable to re-run the model from scratch, read theTo increase the precision of prior distribution, if not specified before you can use the argument

`PriorAge`

. For example:`PriorAge= c(0.01,10)`

for a young sample and`PriorAge = c(10,100)`

for an old sample.If the trajectories are still not convergering, you should whether the choice you made with the argument

`distribution`

and dose-response curves are meaningful.

`LIN_fit`

and `Origin_fit`

,
dose-response curves option
- By default, a saturating exponential plus linear dose response curve
is expected. However, you choose other formula by changing arguments
`LIN_fit`

and`Origin_fit`

in the function.

`distribution`

, equivalent dose dispersion
option
By default, a *cauchy* distribution is assumed, but you can
choose another distribution by replacing the word `cauchy`

by
`gaussian`

, `lognormal_A`

or
`lognormal_M`

for the argument `distribution`

.

The difference between the models: *lognormal_A* and
*lognormal_M* is that the equivalent dose dispersion are
distributed according to:

- a log-normal distribution with mean or average equal to the palaeodose for the first model
- a log-normal distribution with median equal to the palaeodose for the second model.

`SavePdf`

and `SaveEstimates`

option
These two arguments allow to save the results to files.

`SavePdf = TRUE`

create a PDF-file with MCMC trajectories of parameters`A`

(age),`D`

(palaeodose),`sD`

(equivalent doses dispersion). You have to specify`OutputFileName`

and`OutputFilePath`

to define name and path of the PDF-file.`SaveEstimates = TRUE`

saves a CSV-file containing the Bayes estimates, the credible interval at 68% and 95% and the Gelman and Rudin test of convergence of the parameters`A`

,`D`

,`sD`

. For the export the arguments`OutputTableName`

and`OutputTablePath`

have to be specified.

`PriorAge`

option
By default, an age between 0.01 ka and 100 ka is expected. If the
user has more informations on the sample, `PriorAge`

should
be modified accordingly.

For example, if you know that the sample is an older, you can set
`PriorAge=c(10,120)`

. In contrast, if you know that the
sample is younger, you may want to set
`PriorAge=c(0.001,10)`

. Ages of \(<=0\) are not possible. The minimum
bound is 0.001.

**Please note that the setting of PriorAge is not
trivial, wrongly set boundaries are likely biasing your
results.**

In the previous example we considered only the simplest case: one
sample, and one BIN/BINX-file. However, ‘BayLum’ allows to process
multiple BIN/BINX-files for one sample. To work with multiple
BIN/BINX-files, the names of the subfolders need to beset in argument
`Names`

and both files need to be located unter the same
`Path`

.

For the case

`Names <- c("samp1", "samp2")`

the call `Generate_DataFile()`

(or
`Generate_DataFile_MG()`

) becomes as follows:

```
##argument setting
nbsample <- 1
nbbinfile <- length(Names)
Binpersample <- c(length(Names))
##call data file generator
DATA_BF <- Generate_DataFile(
Path = path,
FolderNames = Names,
Nb_sample = nbsample,
Nb_binfile = nbbinfile,
BinPerSample = Binpersample,
verbose = FALSE
)
```

```
Warning in Generate_DataFile(Path = path, FolderNames = Names, Nb_sample = nbsample, : 'Generate_DataFile' is deprecated.
Use 'create_DataFile()' instead.
See help("Deprecated")
```

```
##calculate the age
Age <- Age_Computation(
DATA = DATA_BF,
SampleName = Names,
BinPerSample = Binpersample
)
```

```
Compiling model graph
Resolving undeclared variables
Allocating nodes
Graph information:
Observed stochastic nodes: 12
Unobserved stochastic nodes: 15
Total graph size: 221
Initializing model
```

```
>> Sample name <<
----------------------------------------------
samp1 samp2
>> Results of the Gelman and Rubin criterion of convergence <<
----------------------------------------------
Point estimate Uppers confidence interval
A 1.076 1.101
D 1.082 1.11
sD 1.155 1.244
---------------------------------------------------------------------------------------------------
*** WARNING: The following information are only valid if the MCMC chains have converged ***
---------------------------------------------------------------------------------------------------
parameter Bayes estimate Credible interval
----------------------------------------------
A 2.377
lower bound upper bound
at level 95% 1.1 3.529
at level 68% 1.73 2.744
----------------------------------------------
D 5.918
lower bound upper bound
at level 95% 2.999 8.687
at level 68% 4.563 6.842
----------------------------------------------
sD 0.942
lower bound upper bound
at level 95% 0 2.546
at level 68% 0 0.761
```

The function `Generate_DataFile()`

(or
`Generate_DataFile_MF()`

) can process multiple files
simultaneously including multiple BIN/BINX-files per sample.

We assume that we are interested in two samples named:
*sample1* and *sample2*. In addition, we have two
BIN/BINX-files for the first sample named: *sample1-1* and
*sample1-2*, and one BIN-file for the 2nd sample named
*sample2-1*. In such case, we need three subfolders named
*sample1-1*, *sample1-2* and *sample2-1*; which
each subfolder containing only one BIN-file named
**bin.bin**, and its associated files
**DiscPos.csv**, **DoseEnv.csv**,
**DoseSourve.csv** and **rule.csv**. All of
these 3 subfolders must be located in *path*.

To fill the argument corectly `BinPerSample`

: \(binpersample=c(\underbrace{2}_{\text{sample 1: 2
bin files}},\underbrace{1}_{\text{sample 2: 1 bin file}})\)

```
Names <-
c("sample1-1", "sample1-2", "sample2-1") # give the name of the folder datat
nbsample <- 2 # give the number of samples
nbbinfile <- 3 # give the number of bin files
DATA <- Generate_DataFile(
Path = path,
FolderNames = Names,
Nb_sample = nbsample,
Nb_binfile = nbbinfile,
BinPerSample = binpersample
)
```

`combine_DataFiles()`

If the user has already saved informations imported with
`Generate_DataFile()`

function (or
`Generate_DataFile_MG()`

function) these data can be
concatenate with the function `combine_DataFiles()`

.

For example, if `DATA1`

is the output of sample named
“GDB3”, and `DATA2`

is the output of sample “GDB5”, both data
can be merged with the following call:

```
data("DATA1", envir = environment())
data("DATA2", envir = environment())
DATA3 <- combine_DataFiles(L1 = DATA2, L2 = DATA1)
str(DATA3)
```

```
List of 11
$ LT :List of 2
..$ : num [1:188, 1:6] 4.54 2.73 2.54 2.27 1.48 ...
..$ : num [1:101, 1:6] 5.66 6.9 4.05 3.43 4.97 ...
$ sLT :List of 2
..$ : num [1:188, 1:6] 0.333 0.386 0.128 0.171 0.145 ...
..$ : num [1:101, 1:6] 0.373 0.315 0.245 0.181 0.246 ...
$ ITimes :List of 2
..$ : num [1:188, 1:5] 40 40 40 40 40 40 40 40 40 40 ...
..$ : num [1:101, 1:5] 160 160 160 160 160 160 160 160 160 160 ...
$ dLab : num [1:2, 1:2] 1.53e-01 5.89e-05 1.53e-01 5.89e-05
$ ddot_env : num [1:2, 1:2] 2.512 0.0563 2.26 0.0617
$ regDose :List of 2
..$ : num [1:188, 1:5] 6.14 6.14 6.14 6.14 6.14 6.14 6.14 6.14 6.14 6.14 ...
..$ : num [1:101, 1:5] 24.6 24.6 24.6 24.6 24.6 ...
$ J : num [1:2] 188 101
$ K : num [1:2] 5 5
$ Nb_measurement: num [1:2] 14 14
$ SampleNames : chr [1:2] "samp 1" "samp 1"
$ Nb_sample : num 2
- attr(*, "originator")= chr "create_DataFile"
```

The data structure should become as follows

- 2
`list`

s (1`list`

per sample) for`DATA$LT`

,`DATA$sLT`

,`DATA1$ITimes`

and`DATA1$regDose`

- A
`matrix`

with 2 columns (1 line per sample) for`DATA1$dLab`

,`DATA1$ddot_env`

- 2
`integer`

s (1`integer`

per BIN files here we have 1 BIN-file per sample) for`DATA1$J`

,`DATA1$K`

,`DATA1$Nb_measurement`

.

Single-grain and multiple-grain OSL measurements can be merged in the
same way. To plot the \(L/T\) as a
function of the regenerative dose the function
`LT_RegenDose()`

can be used again:

`plot_RegDosePoints(DATA3)`

*Note: In the example DATA3 contains information from
the samples ‘GDB3’ and ‘GDB5’, which are single-grain OSL measurements.
For a correct treatment the argument SG has to be manually
set by the user. Please see the function manual for further
details.*

If no stratigraphic constraints were set, the following code can be
used to analyse the age of the sample *GDB5* and *GDB3*
simultaneously.

```
priorage = c(1, 10, 10, 100)
Age <- AgeS_Computation(
DATA = DATA3,
Nb_sample = 2,
SampleNames = c("GDB5", "GDB3"),
PriorAge = priorage,
distribution = "cauchy",
LIN_fit = TRUE,
Origin_fit = FALSE,
Iter = 1000,
jags_method = "rjags"
)
```

`Warning: No initial values were provided - JAGS will use the same initial values for all chains`

```
Compiling rjags model...
Calling the simulation using the rjags method...
Adapting the model for 1000 iterations...
Burning in the model for 4000 iterations...
Running the model for 5000 iterations...
Simulation complete
Calculating summary statistics...
Calculating the Gelman-Rubin statistic for 6 variables....
Finished running the simulation
```

```
>> Results of the Gelman and Rubin criterion of convergence <<
----------------------------------------------
Sample name: GDB5
---------------------
Point estimate Uppers confidence interval
A_GDB5 1.001 1.001
D_GDB5 1.011 1.037
sD_GDB5 1.005 1.019
----------------------------------------------
Sample name: GDB3
---------------------
Point estimate Uppers confidence interval
A_GDB3 1.001 1.006
D_GDB3 1.009 1.034
sD_GDB3 1.005 1.018
---------------------------------------------------------------------------------------------------
*** WARNING: The following information are only valid if the MCMC chains have converged ***
---------------------------------------------------------------------------------------------------
>> Bayes estimates of Age, Palaeodose and its dispersion for each sample and credible interval <<
----------------------------------------------
Sample name: GDB5
---------------------
Parameter Bayes estimate Credible interval
A_GDB5 7.137
lower bound upper bound
at level 95% 5.818 8.642
at level 68% 6.265 7.667
Parameter Bayes estimate Credible interval
D_GDB5 17.787
lower bound upper bound
at level 95% 16.599 18.921
at level 68% 17.126 18.347
Parameter Bayes estimate Credible interval
sD_GDB5 4.472
lower bound upper bound
at level 95% 3.317 5.456
at level 68% 3.845 4.88
----------------------------------------------
Sample name: GDB3
---------------------
Parameter Bayes estimate Credible interval
A_GDB3 47.057
lower bound upper bound
at level 95% 36.444 58.321
at level 68% 40.758 51.507
Parameter Bayes estimate Credible interval
D_GDB3 104.848
lower bound upper bound
at level 95% 96.736 112.302
at level 68% 101.188 109.194
Parameter Bayes estimate Credible interval
sD_GDB3 15.951
lower bound upper bound
at level 95% 9.912 22.37
at level 68% 12.604 18.94
----------------------------------------------
```

**Note:** For an automated parallel processing you can
set the argument `jags_method = "rjags"`

to
`jags_method = "rjparallel"`

.

As for the function `Age_computation()`

, the age for each
sample is set by default between 0.01 ka and 100 ka. If you have more
informations on your samples it is possible to change
`PriorAge`

parameters. `PriorAge`

is a vector of
`size = 2*$Nb_sample`

, the two first values of
`PriorAge`

concern the 1st sample, the next two values the
2nd sample and so on.

For example, if you know that sample named *GDB5* is a young
sample whose its age is between 0.01 ka and 10 ka, and *GDB3* is
an old sample whose age is between 10 ka and 100 ka, \[PriorAge=c(\underbrace{0.01,10}_{GDB5\ prior\
age},\underbrace{10,100}_{GDB3\ prior\ age})\]

With the function `AgeS_Computation()`

it is possible to
take the stratigraphic relations between samples into account and define
constraints.

For example, we know that *GDB5* is in a higher
stratigraphical position, hence it likely has a younger age than sample
*GDB3*.

To take into account stratigraphic constraints, the information on
the samples need to be ordered. Either you enter a sample name
(corresponding to subfolder names) in `Names`

parameter of
the function `Generate_DataFile()`

, ordered by order of
increasing ages or you enter saved .RData informations of each sample in
`combine_DataFiles()`

, ordered by increasing ages.

```
# using Generate_DataFile function
Names <- c("samp1", "samp2")
nbsample <- 2
DATA3 <- Generate_DataFile(
Path = path,
FolderNames = Names,
Nb_sample = nbsample,
verbose = FALSE
)
```

```
Warning in Generate_DataFile(Path = path, FolderNames = Names, Nb_sample = nbsample, : 'Generate_DataFile' is deprecated.
Use 'create_DataFile()' instead.
See help("Deprecated")
```

```
# using the function combine_DataFiles()
data(DATA1, envir = environment()) # .RData on sample GDB3
data(DATA2, envir = environment()) # .RData on sample GDB5
DATA3 <- combine_DataFiles(L1 = DATA1, L2 = DATA2)
```

Let `SC`

be the matrix containing all information on
stratigraphic relations for this two samples. This matrix is defined as
follows:

matrix dimensions: the row number of

`StratiConstraints`

matrix is equal to`Nb_sample+1`

, and column number is equal to \(Nb\_sample\).first matrix row: for all \(i\) in \(\{1,...,Nb\_Sample\}\),

`StratiConstraints[1,i] <- 1`

, means that the lower bound of the sample age given in`PriorAge[2i-1]`

for the sample whose number ID is equal to \(i\) is taken into accountsample relations: for all \(j\) in ${2,…,Nb_Sample+1}$ and all \(i\) in \(\{j,...,Nb\_Sample\}\),

`StratiConstraints[j,i] <- 1`

if the sample age whose ID is equal to \(j-1\) is lower than the sample age whose ID is equal to \(i\). Otherwise,`StratiConstraints[j,i] <- 0`

.

To the define such matrix the function *SCMatrix()* can be
used:

In our case: 2 samples, `SC`

is a matrix with 3 rows and 2
columns. The first row contains `c(1,1)`

(because we take
into account the prior ages), the second line contains
`c(0,1)`

(sample 2, named *samp2* is supposed to be
older than sample 1, named *samp1*) and the third line contains
`c(0,0)`

(sample 2, named *samp2* is not younger than
the sample 1, here named *samp1*). We can also fill the matrix
with the stratigraphic relations as follow:

```
Age <-
AgeS_Computation(
DATA = DATA3,
Nb_sample = 2,
SampleNames = c("samp1", "samp2"),
PriorAge = priorage,
distribution = "cauchy",
LIN_fit = TRUE,
Origin_fit = FALSE,
StratiConstraints = SC,
Iter = 1000,
jags_method = 'rjags')
```

`Warning: No initial values were provided - JAGS will use the same initial values for all chains`

```
Compiling rjags model...
Calling the simulation using the rjags method...
Adapting the model for 1000 iterations...
Burning in the model for 4000 iterations...
Running the model for 5000 iterations...
Simulation complete
Calculating summary statistics...
Calculating the Gelman-Rubin statistic for 6 variables....
Finished running the simulation
```

```
>> Results of the Gelman and Rubin criterion of convergence <<
----------------------------------------------
Sample name: samp1
---------------------
Point estimate Uppers confidence interval
A_samp1 1.009 1.015
D_samp1 1.001 1.004
sD_samp1 1.001 1.004
----------------------------------------------
Sample name: samp2
---------------------
Point estimate Uppers confidence interval
A_samp2 1 1
D_samp2 1.006 1.021
sD_samp2 1 1.001
---------------------------------------------------------------------------------------------------
*** WARNING: The following information are only valid if the MCMC chains have converged ***
---------------------------------------------------------------------------------------------------
>> Bayes estimates of Age, Palaeodose and its dispersion for each sample and credible interval <<
----------------------------------------------
Sample name: samp1
---------------------
Parameter Bayes estimate Credible interval
A_samp1 9.723
lower bound upper bound
at level 95% 9.154 10
at level 68% 9.685 10
Parameter Bayes estimate Credible interval
D_samp1 29.329
lower bound upper bound
at level 95% 23.671 34.544
at level 68% 26.608 32.013
Parameter Bayes estimate Credible interval
sD_samp1 67.499
lower bound upper bound
at level 95% 51.782 84.37
at level 68% 56.664 73.926
----------------------------------------------
Sample name: samp2
---------------------
Parameter Bayes estimate Credible interval
A_samp2 10.417
lower bound upper bound
at level 95% 10 11.245
at level 68% 10.001 10.475
Parameter Bayes estimate Credible interval
D_samp2 18.246
lower bound upper bound
at level 95% 17.14 19.437
at level 68% 17.637 18.815
Parameter Bayes estimate Credible interval
sD_samp2 4.561
lower bound upper bound
at level 95% 3.503 5.605
at level 68% 4.006 5.09
----------------------------------------------
```

Thee results can be also be used for an alternative graphical representation:

`plot_Ages(Age, plot_mode = "density")`

```
SAMPLE AGE HPD68.MIN HPD68.MAX HPD95.MIN HPD95.MAX ALT_SAMPLE_NAME AT
1 samp1 9.723 9.685 10.000 9.154 10.000 NA 2
2 samp2 10.417 10.001 10.475 10.000 11.245 NA 1
```

If MCMC trajectories did not converge, it means we should run
additional MCMC iterations.

For `AgeS_computation()`

and `Age_OSLC14()`

models
we can run additional iterations by supplying the function output back
into the parent function. In the following, notice we are using the
output of the previous `AgeS_computation()`

example, namely
`Age`

. The key argument to set/change is
`DATA`

.

```
Age <- AgeS_Computation(
DATA = Age,
Nb_sample = 2,
SampleNames = c("GDB5", "GDB3"),
PriorAge = priorage,
distribution = "cauchy",
LIN_fit = TRUE,
Origin_fit = FALSE,
Iter = 1000,
jags_method = "rjags"
)
```

```
Calling the simulation using the rjags method...
Note: the model did not require adaptation
Burning in the model for 4000 iterations...
Running the model for 5000 iterations...
Simulation complete
Calculating summary statistics...
Calculating the Gelman-Rubin statistic for 6 variables....
Finished running the simulation
```

```
>> Results of the Gelman and Rubin criterion of convergence <<
----------------------------------------------
Sample name: GDB5
---------------------
Point estimate Uppers confidence interval
A_GDB5 1.003 1.004
D_GDB5 1.001 1.001
sD_GDB5 1 1.002
----------------------------------------------
Sample name: GDB3
---------------------
Point estimate Uppers confidence interval
A_GDB3 1.005 1.008
D_GDB3 1.01 1.037
sD_GDB3 1.011 1.041
---------------------------------------------------------------------------------------------------
*** WARNING: The following information are only valid if the MCMC chains have converged ***
---------------------------------------------------------------------------------------------------
>> Bayes estimates of Age, Palaeodose and its dispersion for each sample and credible interval <<
----------------------------------------------
Sample name: GDB5
---------------------
Parameter Bayes estimate Credible interval
A_GDB5 9.724
lower bound upper bound
at level 95% 9.18 10
at level 68% 9.689 10
Parameter Bayes estimate Credible interval
D_GDB5 29.376
lower bound upper bound
at level 95% 24.082 34.372
at level 68% 26.946 32.151
Parameter Bayes estimate Credible interval
sD_GDB5 67.626
lower bound upper bound
at level 95% 49.601 83.822
at level 68% 58.144 74.668
----------------------------------------------
Sample name: GDB3
---------------------
Parameter Bayes estimate Credible interval
A_GDB3 10.415
lower bound upper bound
at level 95% 10 11.244
at level 68% 10 10.472
Parameter Bayes estimate Credible interval
D_GDB3 18.373
lower bound upper bound
at level 95% 17.111 19.592
at level 68% 17.747 18.97
Parameter Bayes estimate Credible interval
sD_GDB3 4.638
lower bound upper bound
at level 95% 3.726 5.866
at level 68% 4.188 5.272
----------------------------------------------
```

Combès, B., Philippe, A., Lanos, P., Mercier, N., Tribolo, C., Guerin, G., Guibert, P., Lahaye, C., 2015. A Bayesian central equivalent dose model for optically stimulated luminescence dating. Quaternary Geochronology 28, 62-70. doi: 10.1016/j.quageo.2015.04.001

Combès, B., Philippe, A., 2017. Bayesian analysis of individual and systematic multiplicative errors for estimating ages with stratigraphic constraints in optically stimulated luminescence dating. Quaternary Geochronology 39, 24–34. doi: 10.1016/j.quageo.2017.02.003

Philippe, A., Guérin, G., Kreutzer, S., 2019. BayLum - An R package for Bayesian analysis of OSL ages: An introduction. Quaternary Geochronology 49, 16-24. doi: 10.1016/j.quageo.2018.05.009

Robert and Casella, 2009. Introducing Monte Carlo Methods with R. Springer Science & Business Media.

Tribolo, C., Asrat, A., Bahain, J. J., Chapon, C., Douville, E., Fragnol, C., Hernandez, M., Hovers, E., Leplongeon, A., Martin, L., Pleurdeau, D., Pearson, O., Puaud, S., Assefa, Z., 2017. Across the Gap: Geochronological and Sedimentological Analyses from the Late Pleistocene-Holocene Sequence of Goda Buticha, Southeastern Ethiopia. PloS one, 12(1), e0169418. doi: 10.1371/journal.pone.0169418