|
|
|
When the program has been installed properly on your machine, you should be able to run it by supplying appropriate input. This document describes how input is organized. A few sample runs are contained in the distribution, see the Examples document for a description.
Input is structured by keywords, or keys. A key is a string of letters, dollar signs ($), and digits. It must not start with a digit. It must not contain any other character, in particular not any blank.
Key-controlled input occurs in two forms: either one record (which contains both the key and/or associated data) or a sequence of records, collectively denoted as a key block. The first record of the block specifies the key (and may supply additional information); the block is closed by the `end-key' code: a record containing only two asterisks ( ** ). The other records in the block provide data associated with the key.
The form to be used for a key is not optional: each admissible key corresponds to a particular form. The block form is used for keys that relate to 'lists' of data, such as atomic coordinates or basis functions.
The first and the last record of the input file are not key-controlled.
The first record of input is used as an identifying 'title' for the run and may contain any string. This is different from the molecular code, where the "title" is specified explicitly with the key "Title" and may be put on any record of the input file. Note carefully, that in BAND, the first line of input is always just the title; any `key' that you may intend to specify on the first line will be ignored.
The input file should end with a record END INPUT, that is, the program reads input until such a record is encountered or until the Fortran end-of-file condition becomes true, whichever comes first.
END INPUT is not a key.
Summarizing, the input file must have the following format: