In order to help keep track of your files, you may want to adopt a file naming standard, at least as far as the file name extensions are concerned. Here are some suggestions for file name extensions:

.LG4        model files (Windows only),

.LNG        model files in text format,

.LTF        script files,

.LDT        included data files,

.LGR        report files.

 

A Note to Windows Users:

If you use the default LINGO format (.LG4) for a model, the file will be saved in a special binary format. Files in this format will only be readable by Windows versions of LINGO, and will appear garbled if read into other applications. This binary format allows LINGO models to function as both Object Linking and Embedding (OLE) containers and servers, allows for embedding of objects (e.g., bitmaps), and permits custom formatting of model text. Thus, you will generally want to use the .LG4 format. Cases where you must use a text format are:

 

         1. a model that must be transferred to another platform or application,

         2. a LINGO script file, or

         3. a LINGO data file to be included with @FILE.

 

LINGO anticipates this by saving any file with an extension other than .LG4 as text.

You can force LINGO to always use the .LNG text format for models by checking the .LNG box on the Interface tab of the Solver|Options dialog box. Any special formatting of the text (e.g. bold fonts) will be lost when a model is saved in this format. Also, models saved as text may not function as OLE containers or servers.

 

On platforms other than Windows, LINGO always saves files in text format.