\documentclass[a4paper]{article}
%\VignettePackage{scape}
%\VignetteIndexEntry{Importing results}
\usepackage{parskip}
\usepackage{hyperref}
\newcommand{\p}[1]{{\fontseries{b}\selectfont #1}}
\newcommand{\R}{\textsf{R}}
\newcommand{\scape}{{\fontseries{b}\selectfont scape}}
\begin{document}

\title{Importing results from a\\statistical catch-at-age model}
\author{Arni Magnusson}
\maketitle

\section*{Introduction}

This is a brief description of how to import statistical catch-at-age model
output from any stock assessment into \scape. The user is expected to be
familiar with basic \R\ concepts, such as reading data from text files and
manipulating lists and data frames.

A general introduction to the \p{scape} and \p{plotMCMC} packages is in the
vignette \href{dsc-vignette.pdf}{R goes fishing}.

First, take a look at how the example assessments were imported using
\verb|importCol()|, which is custom-made for Coleraine output files:

{\footnotesize
\begin{verbatim}
x.cod  <- importCol("c:/scape/data/cod.res", Dev=T, Survey=T, CAc=T, CAs=T)
x.oreo <- importCol("c:/scape/data/oreo.res", CPUE=T, Survey=T, CLc=T, CLs=T, LA=T)
x.sbw  <- importCol("c:/scape/data/sbw.res", Dev=T, Survey=T, CAc=T)
x.ling <- importCol("c:/scape/data/ling.res", Dev=T, CPUE=T, Survey=T, CAs=T, CLc=T)
edit(importCol)
\end{verbatim}
}

The \verb|cod|, \verb|ling|, and \verb|sbw| assessments were run in Coleraine
3.2 and all data and fitted values are stored in `data/cod.res' and
`data/sbw.res'. The oreo assessment, on the other hand, was run in Coleraine 4.2
which incorporates uncertainty about the von Bertalanffy growth curve. The oreo
data and fitted values are extracted from `oreo.res', `oreo.txt', and
`l\_at\_age.dat'. Although the `*.res' files may not be the best examples of how
to organize model output, the \verb|importCol()| function demonstrates some
parsing techniques. The key functions are:

{\footnotesize
\begin{verbatim}
?read.table  # creates data frame
?scan        # creates vector, where each element is one token
?readLines   # creates vector, where each element is one line of text
\end{verbatim}
}

Now take a close look at each element:

{\footnotesize
\begin{verbatim}
library(gdata)
ll(x.cod)
x.cod$N       # N@A
x.cod$B       # biomass, yield, recruitment
x.cod$SelMat  # selectivity, maturity
x.cod$Dev     # recruitment deviates
x.cod$Survey  # survey abundance indices
x.cod$CAc     # commercial C@A
x.cod$CAs     # survey C@A
\end{verbatim}
}

Notice how tabular data like N\@A and C\@A are in long format, and look more
familiar when cross-tabbed:

{\footnotesize
\begin{verbatim}
xtabs(N~Year+Age, data=x.cod$N)
\end{verbatim}
}

\section*{Three approaches}

There are mainly three approaches for importing assessment model results into
\scape:

\begin{enumerate}
  \item Read in text file(s) in whatever format output by the model, and rearrange.

  This approach is recommended when the assessment model code should not be
  changed and/or when file size matters. Coleraine output files, for example,
  have remained the same for years and other software depends on the current
  format. \R\ is quite good at parsing data from text files, and any
  standardized format will do. A well formed output file might start each entry
  with a unique label, followed by the dimensions, and then the data in a
  compact layout:

  {\footnotesize
\begin{verbatim}
Commercial C@A
Years 1971-2002
Ages  1-8
SS    50
Obs
0.000000000 0.000000000 0.084548800 ...
0.000000000 0.000000000 0.069520400 ...
0.000000000 0.000000000 0.270907000 ...
...
Fit
0.000638965 0.005390050 0.051482100 ...
0.000409886 0.013909100 0.051432000 ...
0.000714247 0.008321580 0.123764000 ...
...
\end{verbatim}
  }

  \item Read in text file(s) where results are rolled out, like in \scape.

  This approach is recommended for model developers who would like to make it
  easy to import the results into \R\ and \scape. The assessment model is
  specifically coded to write output files that are easily digested by \scape,
  resulting in a simple \verb|importModel()| function, and verbose text files:

  {\footnotesize
\begin{verbatim}
Commercial C@A
Gear Year SS Sex    Age Obs        Fit
1    1971 50 Unisex 1   0.00000000 0.000638965
1    1971 50 Unisex 2   0.00000000 0.005390050
1    1971 50 Unisex 3   0.08454880 0.051482100
...
\end{verbatim}
  }

  \item Read in \R\ code.

  The estimation model could output \R\ code, instead of text files. For
  example, `results.R' could look similar to the R source code created by
  \verb|dump("x.cod", file="x.cod.R")|. Prager and Williams
  (http://cran.r-project.org/contrib/extra/x2r/00ReadMe-X2R.html) have written
  C++ and Fortran libraries to enable the model developer to write data as \R\
  objects.

\end{enumerate}

\end{document}
