RunFn: Run ageing error model

In nwfsc-assess/nwfscAgeingError: Source Code for Punt et al. (2008): Ageing Error and Imprecision

Run ageing error model

Description

Run the Punt et al. (2008) ADMB-based ageing error model from within R.

Usage

RunFn(
  Data,
  SigOpt,
  KnotAges,
  BiasOpt,
  NDataSets = 1,
  MinAge,
  MaxAge,
  RefAge,
  MinusAge,
  PlusAge,
  MaxSd,
  MaxExpectedAge,
  SaveFile,
  EffSampleSize = 0,
  Intern = TRUE,
  AdmbFile = NULL,
  JustWrite = FALSE,
  CallType = "system",
  ExtraArgs = " -est",
  verbose = TRUE
)

Arguments

Data	This is the data set with the first column being an integer providing the number of otoliths that are included in the row and the subsequent columns are the reader or lab estimated ag,e where each reader/lab has a unique reading error and bias. The modeling framework allows for, at most, 15 readers, i.e., 16 columns. There should not be any identical rows in the data frame because otoliths that have the exact same read from every reader/lab should be combined into a single row with the count as the first column. If you failed to combine identical rows prior to running the model, you will be alerted with an error and the XXX.rep file will have a properly formatted data which can be' cut-pasted into a XXX.dat file for use. Missing reads from a given reader/lab should be entered as -999. Order your reader/lab columns such that similar readers/labs are located next to one another because columns to the right can mirror columns to their immediate left in terms of parameter estimates.
SigOpt	This a vector with one entry for each reader (i.e., length(SigOpt) == NCOL(Data) -1). Each entry specifies the functional form of reading error as a function of true age. Possible entries include the following: -0-9+ Mirror the standard deviation of another reader, where the negative integer corresponds to the column of the reader/lab that is being mirrored minus one, e.g., -1 causes it to mirror reader/lab 1, for which data is stored in the second column of Data. This number must be lower than -1 times the current position in the vector. 0 No error. But, there could be potential bias. 1 Constant coefficient of variation, i.e., a 1-parameter linear relationship of the standard deviation with the true age. 2 Curvilinear standard deviation, i.e., a 3-parameter Hollings-form relationship of standard deviation with true age. 3 Curvilinear coefficient of variation, i.e., a 3-parameter Hollings-form relationship of coefficient of variation with true age. 5 Spline with estimated slope at beginning and end where the number of parameters is 2 + number of knots. 6 Linear interpolation with a first knot of 1 and a last knot of the maximum age, i.e., MaxAge.
KnotAges	Ages associated with each knot. This is a necessary input for SigOpt = 5 or SigOpt = 6.
BiasOpt	A vector with one entry for each reader/lab specifying the type of bias specific to each reader. Positive values lead to estimated parameters and negative values are used for shared parameters between readers, just like with SigOpt. Parameter sharing is common when there is more than one reader in a lab working together to refine their methods such that they have matching techniques. Possible entries include the following: -0-9+ Mirror the bias of another reader, where the negative integer corresponds to the column of the reader/lab that is being mirrored minus one, e.g., -1 causes it to mirror reader/lab 1, for which data is stored in the second column of Data. This number must be lower than -1 times the current position in the vector. 0 Unbiased, where at least one reader has to be unbiased. 1 Constant coefficient of variation, i.e., a 1-parameter linear relationship of bias with true age. 2 Curvilinear, i.e., a 2-parameter Hollings-form relationship of bias with true age. An example entry for the situation where you have seven readers and you assume that the first reader is unbiased, readers 2-7 have a curvilinear bias, reader 3 shares parameters with reader 2, reader 5 shares parameters with reader 4, and reader 7 shares parameters with reader 6 would look like c(0, 2, -2, 2, -4, 2, -6).
NDataSets	This is generally 1 and other values are not implemented.
MinAge	An integer, specifying the minimum possible "true" age.
MaxAge	An integer, specifying the maximum possible "true" age.
RefAge	An arbitrarily chosen age from which "true" age-composition fixed-effects are calculated as an offset. This has no effect on the answer but could potentially effect estimation speed.
MinusAge	The minimum age for which an age-specific age-composition is estimated. Ages below MinusAge have "true" proportion-at-age (P_{a}) estimated as P_a = P_{MinusAge}*exp^{(\beta*(MinusAge - a))} , where beta is an estimated log-linear trend in the "true" proportion-at-age. If MinusAge = MinAge, beta is not estimated.
PlusAge	Identical to MinusAge except defining the age above with age-specific age composition is not estimated.
MaxSd	An upper bound on possible values for the standard deviation of reading error.
MaxExpectedAge	Set to MaxAge.
SaveFile	Directory where agemat.exe is located and where all ADMB intermediate and output files should be located. If AdmbFile is specified then agemat.exe is copied from that directory to SaveFile.
EffSampleSize	Indicating whether effective sample size should be calculated. Missing values in the data matrix will cause this to be ineffective, in which case this should be set to 0.
Intern	A logical input that controls the amount of output displayed, where TRUE indicates that ADMB output should be displayed in R and FALSE leads to the suppression of this information.
AdmbFile	An optional character entry that specifies the directory from which agemat.exe is to be copied from to SaveFile.
JustWrite	A logical input that allows just the data files to be written without running ADMB executable.
CallType	Either "system" or "shell" depending on Operating System or how R is being run. The default is "system".
ExtraArgs	A string of characters providing extra arguments passed to ADMB. The default is " -est".
verbose	A logical input that controls the amount of feedback users receive from the program. The default is to provide the most output as possible with verbose = TRUE.

Details

The premise of Punt et al. (2008) is to calculate the likelihood of model parameters given an observed data set of otolith age reads from multiple age readers. For each reader/lab, two parameters are defined, one for standard deviation and one for bias. The model calculates the expected age of each read and the standard deviation of a normally distributed reading error given the true age of an otolith. These relationships can be linear or curvilinear.

The true age is obviously an unobserved process and can be considered a random effect. Thus, the software computes the likelihood while summing across all possible discrete values for the true age of each otolith. This true age requires a hyperdistribution that represents the prior probability that an otolith is any given age. The hyperdistribution is controlled by a set of hyperparameters and the parameters that govern the standard deviation and bias of each age reader/lab. Specifically, one hyperparameter is estimated for every age between and including the MinusAge and PlusAge. Ages outside of this range have a prior proportion at age defined as a loglinear deviation from the proportion at age for the extreme ages, i.e., MinusAge and PlusAge. The slope of these loglinear deviations thus constitutes an additional 1 or 2 fixed effect parameters. The true proportion at age is then calculated from these fixed effects and loglinear slope parameters by normalizing the resulting distribution such that it sums to one.

Author(s)

James T. Thorson, Ian J. Stewart, Andre E. Punt, Ian G. Taylor

See Also

• StepwiseFn() will run multiple models.

• PlotOutputFn() will help summarize the output.

Examples

example(SimulatorFn)
## Not run: 
utils::write.csv(AgeReads,
  file = file.path(getwd(), "Simulated_data_example.csv"))

## End(Not run)

##### Format data
Nreaders <- ncol(AgeReads)
# Change NA to -999 (which the Punt software considers missing data)
AgeReads <- ifelse(is.na(AgeReads), -999, AgeReads)

# Potentially eliminate rows that are only read once
# These rows have no information about reading error, but are potentially
# informative about latent age-structure. It is unknown whether eliminating
# these rows degrades estimation of error and bias, and is currently
# recommended to speed up computation
if (FALSE) {
  KeepRow <- ifelse(
    rowSums(ifelse(AgeReads == -999, 0, 1), na.rm = TRUE) <= 1,
    FALSE, TRUE
  )
  AgeReads <- AgeReads[KeepRow, ]
}

# AgeReads2 is the correctly formatted data object
AgeReads2 <- rMx(c(1, AgeReads[1, ]))

# Combine duplicate rows
for (RowI in 2:nrow(AgeReads)) {
  DupRow <- NA
  for (PreviousRowJ in 1:nrow(AgeReads2)) {
    if (all(
      AgeReads[RowI,1:Nreaders] == AgeReads2[PreviousRowJ,1:Nreaders+1]
    )) {
      DupRow <- PreviousRowJ
    }
  }
  if (is.na(DupRow)) {# Add new row to AgeReads2
    AgeReads2 <- rbind(AgeReads2, c(1, AgeReads[RowI, ]))
  }
  if(!is.na(DupRow)){# Increment number of samples for previous duplicate
    AgeReads2[DupRow,1] <- AgeReads2[DupRow,1] + 1
  }
}

######## Determine settings for ADMB
# Define minimum and maximum ages for integral across unobserved ages
MinAge <- 1
MaxAge <- ceiling(max(AgeReads2[,-1])/10)*10
BiasOpt <- c(0, -1, 0, -3)
SigOpt <- c(1, -1, 6, -3)
# Necessary for SigOpt option 5 or 6
KnotAges <- list(NA, NA, c(1, 10, 20, MaxAge), NA)

##### Run the model (MAY TAKE 5-10 MINUTES)
## Not run: 
fileloc <- file.path(tempdir(), "age")
dir.create(fileloc, showWarnings = FALSE)
RunFn(Data = AgeReads2, SigOpt = SigOpt, KnotAges = KnotAges,
  BiasOpt = BiasOpt,
  NDataSets = 1, MinAge = MinAge, MaxAge = MaxAge, RefAge = 10,
  MinusAge = 1, PlusAge = 30, SaveFile = fileloc,
  AdmbFile = file.path(system.file("executables",
    package = "nwfscAgeingError"), .Platform$file.sep),
  EffSampleSize = 0, Intern = FALSE, JustWrite = FALSE, CallType = "shell"
)

## End(Not run)

nwfsc-assess/nwfscAgeingError documentation built on Sept. 24, 2023, 10:19 a.m.