7.6 Data

Data are defined as a sequence of numbers, expressions, or strings, separated by commas or blanks. Generally, the order of data is essential. Empty fields are interpreted as zeros. Strings and variables must begin with a character [A-Z]. If $+$ or $-$ follows blank and directly precedes a number or variable it is interpreted as sign and not a binary operator. If there are no blanks before and after such operators, or blanks follow them, they are interpreted as binary operators. Examples:

3 - 4 4	yields [-1,4]
3-4 4	yields [-1,4]
3 -4 4	yields [3,-4,4]
3,-4 4	yields [3,-4,4]
3, -4, 4	yields [3,-4,4]

Expressions (including numbers) may contain variables.

Examples for the use of data: geometry and basis input, LATTICE, OCC, CLOSED, CORE, WF directives.

In some cases several lines of data are needed for a certain command or directive; in such cases the data must follow directly the corresponding command$\vert$directive, and must be enclosed in square brackets:

COMMAND,options
$\left[ data \right]$

Normally, the input format of data is MOLPRO style, i.e., numbers are separated by commas, and variables as well as expressions can be used.

If data are included using external files, the input format of data is free format: no commas are needed, but no variables and expressions can be used.