3.2.7 The VARIABLES or COLUMNS Data Cards
(Variable/Column-Wise)

The VARIABLES or COLUMNS indicator cards are used interchangeably to announce the (problem) variables for the minimization. In addition, the entries for the linear elements are input here. The user may also give a scaling factor for the entries in any column. The syntax for data following this indicator card is given in Figure 3.8.

Figure 3.8: Possible data cards for VARIABLES or COLUMNS (column-wise)

The string varbl-name in data field 2 gives the name of the variable (or column) under consideration. This name may be up to ten characters long excepting that the name `SCALE' is not allowed. If data field 1 holds the character X or Z, an array of variables is to be defined. In this case, the expanded array name of the variables (or columns) must be valid and the integer indices must have been defined in a parameter assignment (see Section 3.2.3).

The string $$$$$$$$$$ in data field 3 is used for five purposes.

• If the string is empty, the card is just defining the name of a problem variable.
• It may be used to specify that the variable mentioned in field 2 occurs in the linear element for the group given in field 3. In this case, the string in field 3 must have been defined in the GROUPS section. If an array definition is being made, the string in field 3 must be an array name.
• It may be used to announce that all the entries in the linear elements for the variable under consideration are to be scaled; in this case field 3 will contain the string `SCALE'.
• It may be used to specify that the variable(s) mentioned in field 2 is(are) only allowed to take integer values. In this case field 3 will contain the string 'INTEGER'.
• It may be used to specify that the variable(s) mentioned in field 2 is(are) only allowed to take the values 0 or 1. In this case field 3 will contain the string 'ZERO-ONE'.

A numerical value, whose purpose depends on the string in the previous field, is now specified. On Z cards, the value is that previously associated with the real parameter r-p-a-name in field 5. On other cards, the actual numerical value numerical-vl may occupy up to 12 characters in data field 4.

If field 3 indicates that an entry for the linear element for a group is to be defined, the specified numerical value gives the coefficient of that entry. If, on the other hand, field 3 indicates that all entries for the variable in field 2 are to be scaled, the specified value gives the scale factor, that is the factor by which each entry is to be divided.

On non Z cards, the strings in fields 5 and 6 are optional and are used exactly as for strings 3 and 4 to define further entries or a scale factor.