6.2 Data File

The data file is mandatory. It gives the traits to be analysed, and all information on effects in the model of analysis. It is expected to have the following features:



1. There is no ’default’ name for the data file. File names up to 30 characters long are accommodated.
2. Variables in the data file should be in fixed width columns, separated by spaces.
3. Each column, up to the maximum number of columns to be considered (= number of variables specified in the parameter file), must have a numerical value – even if this column is not used in the analysis, i.e. no ‘blank’ values !
4. All codes of effects to be considered (fixed, random or ‘extra’ effects) must be positive integer variables, i.e. consist of a string of digits only.
The maximum value allowed for a code is 2147483647  , i.e. just over 2 billion.
5. All traits and covariables (including control variables) are read as real values, i.e. may contain digits, plus or minus signs, and Fortran type formatting directives only.

N.B.: Calculations in WOMBAT use an operational zero (default value:  − 8
10  ), treating all smaller values as zero. To avoid numerical problems, please ensure your traits are scaled so that their variances are in a moderate range (something like 10−5  to 105  ).


6. Any alphanumeric strings in the part of the data file to be read by WOMBAT are likely to produce errors !
7. For multi-trait analyses, there should be one record for each trait recorded for an individual1. The trait number for the record should be given in the first column.

No special codes for ’missing values’ are available – missing traits are simply absent records in the data file.
8. The data file must be sorted in ascending order, according to :

i)
the individual (or ’subject’) for which traits are recorded, and
ii)
according to the trait number within individual.
iii)
For RR analyses, records are expected to be sorted according to the value of the control variable (within individual and trait number) in addition.

N.B.: WOMBAT does not allow ‘repeated’ records for individual points on the trajectory in RR analyses, i.e. you can not have multiple observations for an individual with the same value of the control variable.


9. For multivariate analyses combining traits with repeated and single records, the traits with repeated records need to have a lower trait number than those with single records only.

To facilitate annotation of the data file (e.g. column headers, date of creation, source), WOMBAT will skip lines with a ’#’ (hash sign) in column 1 at the beginning of the file - there is no limit on the number, n  , of such lines, but they must represent the first n  lines (any ’#’ elsewhere will cause an error).

1Yes, this may result in some duplication of codes, if the model is the same for all traits !