17. GET2COL

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General introduction

GET2COL is a utility for post-processing standard results files produced by the models within HGSYSTEM, creating output files for submission to suitable user-selected plotting packages.
The GET2COL program selects any two columns from a multi-column HGSYSTEM results file and puts these two columns in a new file. These two columns can then be plotted.
GET2COL can in fact be used for any multi-column input file.

The GET2COL utility has been completely revised for HGSYSTEM version 3.0. It can now be run in 'batch' mode, that is it can be used as all other main HGSYSTEM modules, and GET2COL reads its input data from an input file having the same structure as all other HGSYSTEM input files.

Range of applications and limitations

As well as HGSYSTEM result files the post-processor can handle any file as long as the format is standard ASCII and not binary.

Guidance for use

When first used to post-process the HGSYSTEM output for a new case, it is recommended that the row numbers are not specified by the user, but allowed to take default values. Such usage has the advantage of requiring no data analysis by the user, enabling automatic running of the post-processor and the production of an initial useful output file, assuming the output column requirements are already known and specified. If needed, further refinement of the row requirements can then be made in a meaningful manner.

Despite the above recommendation, restraint should be shown if the result file to be post-processed is likely to be very large. This may happen, for example, where very small output steps or very stringent termination criteria were selected when running the model to produce the result file. In such cases, it is recommended that the user looks at the full range of data using a large row extraction frequency, or looks in detail at a section of the data using a small row extraction frequency. Such usage also avoids the danger of exceeding size limitations in the user's preferred plotting package.

Care should be taken when using GET2COL with files which have so called problem columns containing blank or non-numeric values. Such files are post-processed successfully if both columns selected by the user lie to the left of any problem columns, otherwise incorrect values are obtained. Such a situation should not arise for existing HGSYSTEM 3.0 result files.

A standard report file 'casename.G2R' containing the number of data-pairs read from the multi-column input file and written to the 2-column output file, is always produced.

GET2COL INPUT FILE PARAMETERS

A description of all the input parameters that can occur in a GET2COL input file will be given.

The GET2COL input file has the DOS filename 'casename.G2I', where 'casename' is the user-supplied name of the problem.

When creating an input file the user should ensure that each specified output file has a unique filename, and that existing files having such names are deleted or renamed before GET2COL is run, because GET2COL assumes that files with the specified names do not yet exist. An error will occur if the file does exist.

In the following, actual keywords are given in capitals and in bold. The descriptions of less important parameters or parameters that need not normally be set by the user, are given in a smaller font.

All parameters occur in blocks preceded by a specific block keyword. For GET2COL these block keywords are: FILES, COLUMNS and ROWS.

The FILES block is mandatory and specifies the filenames of the input and output files.

INFILE Filename of the multi-column input file 'filename.ext' (full pathname if required).
  At most 40 alphanumeric characters.
  Mandatory.
OUTFILE Filename of the two-column output file 'filename.ext' (full pathname if required).
  At most 40 alphanumeric characters.
  Mandatory.

COLUMNS block is mandatory and specifies the two column numbers from the multi-column input file required to produce the two-column output file.
COLUMN1 First column required (-).
  1 <= COLUMN1 <= 19.
  Mandatory.
COLUMN2 Second column required (-).
  2 <= COLUMN2 <= 20.
  Mandatory.
  Must be greater than COLUMN1.

ROWS block is optional and may be used to specify the row numbers from the multi-column input file required to produce the two-column output file. If this block is not used, the default is to include all rows from the input file, up to a maximum of 100000 rows.

ROWMIN First row required (-).
  1 <= ROWMIN <= 99999.
  Optional, default 1.
ROWMAX Last row required (-).
  2 <= ROWMAX <= 100000.
  Optional, default 100000.
  ROWMAX must be greater than ROWMIN.
FREQ Frequency for extracting data (-).
  1 <= FREQ <= 10000.
  Optional, default 1.

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