In any input field, data can be entered in the form of expressions. Numbers and variables are special cases of expressions. An expression is typed in Fortran style and may contain any number of nested parenthesis. The standard intrinsic functions are also available (see next section). MOLPRO understands both arithmetic and logical expressions. The result of an arithmetic expression is a real (double precision) number. Internally, all integers are also converted to real numbers. The result of a logical expression is either .TRUE. or .FALSE.. Internally, .TRUE. is stored as a one (1.0), and .FALSE. as zero (0.0). Expressions may contain any number of variables.
The following standard operations can be performed :