the Index Display Matrix Pointer Vector; for, as mentioned earlier,

analysis on variable indices will largely be performed on their Index

Display Matrices. The third word serves as a flag which indicates

whether or not the variable index has been output set assigned. If it

has, the next word indicates what the output is if it is a simple offset

from the function index. If the output is not a simple offset the Index

Display Matrix must be examined to determine the index output. The

fifth word of the VIDV cell is a flag indicating whether or not the

variable index is defined by a range or a list. The sixth word

indicates whether the index is to be incremented in ascending or

descending order. The rest of the VIDV cell depends on whether the

index is defined by a range or a list.

 If the index is defined by a range, the length of the VIDV cell is

 fixed, as there are five more entries for a range defined index. The

 first entry indicates whether the lower limit of the range is offset

 from the lower limit of the function index or from the function index

 itself. The next entry indicates what that offset is. The next two

 entries serve the same purpose for the variable index range upper limit.

 The last entry is the range increment. If the index is defined by a

 list, the length of the VIDV cell is variable. This is because the

 number of list elements is variable. Within the list definition section

 of the VIDV cell, the first entry indicates how many list elements

 there are. Subsequently each list element occupies two entries, the

 first of these being the offset from the function index value and the

 second being a weight which is used by some of the analysis routines.

 To facilitate analyses performed on function and variable indices