When starting the code (e.g. type ./tetr), it first checks if the variable $HOME_TETR is set correctly:
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...... TETR is an interface to VASP/SIESTA/etc .......
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>>>>>>>> 1st release: 25.07.1994
>>>>>>>> Version : 3.92h
>>>>>>>> Build : Tue Jun 21 19:39:20 BST 2005
>>>>>>>> today : Wed Jul 13 00:52:31 BST 2005
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...... inquiries to L. Kantorovich .........
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OK! File /home/lev/TOOLS/TETR/tetr exists!
.... TETR home directory: /home/lev/TOOLS/TETR
OK! File /home/lev/TOOLS/TETR/symgrp.rep exists!
OK! File /home/lev/TOOLS/TETR/collect_forces exists!
OK! File /home/lev/TOOLS/TETR/get_forces exists!
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It must find the executables tetr and get_forces, a script collect_forces and the file symgrp.rep. At the same time, the current date and version are shown.
Next, the following first menu is displayed that prompts a user to choose the input format for the geometry, the so-called Input-menu:
Choose the input format:
1. open input as CASTEP [ *.geom]
2. open input as CETEP / old CASTEP
3. open input as VASP
4. open input as SIESTA [ *.fdf ]
5. open output as SIESTA [ *.XV ]
6. open as XYZ-type file [ *.xyz ]
7. NEW or go directly to the main menu
8. QUIT
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Options 1-6 imply existing files of the specified formats; you will then be prompted to choose the file name, and the input file will be read in. If successful, you will be prompted to the main menu, described in Section 2.6.1. If not (e.g. due to an error in the input file or becuase the latter does not exist), you will be prompted again to the menu above.
The option 7 corresponds to starting from scratch rather then reading an existing input file of one of the DFT codes. In this case a new input file is to be constructed and then saved in one of known formats.