Code Manual for CONTAIN 2.0 - Federation of American Scientists

The ordering requirements within an input block are based on a hierarchy indicated in the template
by the level of indentation used to display a group of keywords and variables. Thus, the lowest level
in the hierarchy is occupied by the group placed furthest to the right.
The first type of ordering requirement is related to the order of variables: a contiguous group of
variables must be specified in the input in the order given in the template. A group of variables is
considered contiguous if the variables are all at the same level in the hierarchy and are not separated
by a keyword at any level. (Note that a contiguous group of variables may and often does consist
of only one variable, especially one following a keyword.) Furthermore, a contiguous group of
variables that immediately follows a keyword at the same level in the hierarchy must be specified
immediately after that keyword. Most variables follow such a keyword. However, in some cases
they do not. In such cases, the leading variable of the contiguous group has the same function as a
keyword in defining ordering requirements. Such leading variables are often character variables
representing the name of an option or material.
As an example, a keyword PVALUE that has “n” values of a variable “p” associated with it might
be displayed in the template in the form:
PVALUE n (p)
where the parentheses imply that the enclosed item(s) should be repeated as necessary. This group
of keywords and variables is considered to be at the same (the fust) level in the hierarchy, since only
one (the zero) level of indentation is used for the group. The variables are contiguous and follow
a keyword in the template and thus must be specified in the order given immediately after the
keyword. If there are four values 1.0, 2.0, 3.0, and 4.0 of “p” associated with PVALUE, the
corresponding input would have the form:
PVALUE 41.02.03 .04.0
The second type of ordering requirement involves sub-blocks of data. A sub-block at a given level
in the hierarchy is basically a contiguous group of keywords and variables at the given level or lower
that is not separated by keywords or variables at a higher level. The sub-block boundaries are not
uniquely specified according to this definition. For present purposes additional rules are needed to
make the division into sub-blocks at a given level unique. Because of the variety of ways that subblocks
are recognized in the code, these rules are rather complex: (1) With the exception of an
end-of-information (EOl) keyword, a keyword or leading variable at the same ievel as the sub-block
marks the beginning of a new sub-block, as does an indentation to a lower level than the sub-block.
If such a keyword or leading variable is present, it is considered included in the sub-block it begins
and also is considered to terminate the sub-block at the same level immediately preceding it, if one
exists. If such a keyword is present, it is called a leading keyword. An EOI keyword at a given level
has a different effect: it terminates the preceding sub-block at the same level and is considered
included in the sub-block it terminates. Note that a sub-block can have at most one non-EOI
keyword or leading variable at the same level as the sub-block. Thus, at the lowest level in an input
block, individual non-EOI keywords and leading variables each represent a different sub-block.
Rev O 14-7 6/30/97