Data structures store the information on which a Genstat program operates. Structures can be defined, or declared, by a Genstat statement known as a declaration. The directive for declaring each type of structure has the same name as given to that type of structure, for example SCALAR to declare a scalar (or single-valued numerical structure), and so on. These are the directives, with details of their corresponding data structures:
SCALAR |
single number |
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VARIATE |
series of numbers |
TEXT |
series of character strings (or lines of text) |
FACTOR |
series of group allocations (using a pre-defined set of numbers or strings to indicate the groups) |
MATRIX |
rectangular matrix |
SYMMETRICMATRIX |
symmetric matrix |
DIAGONALMATRIX |
diagonal matrix |
TABLE |
table (to store tabular summaries like means, totals etc) |
DUMMY |
single identifier |
POINTER |
series of identifiers (e.g. to represent a set of structures) |
EXPRESSION |
arithmetic expression |
FORMULA |
model formula (to be fitted in a statistical analysis) |
LRV |
latent roots and vectors |
SSPM |
sums of squares and products with associated information such as means |
TREE |
tree (as used to represent classification trees, identification keys and regression trees) |
TSM |
model for Box-Jenkins modelling of time series |
You can rename a data structure, or create a new one with attributes the same as those of an existing structure.
RENAME |
renames a data structure, to give it a new identifier |
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DUPLICATE |
forms new data structures with attributes taken from an existing structure |
PDUPLICATE |
duplicates a pointer, with all its components |
SETNAME |
sets the identifier of a data structure to be one specified in a text |
You can also define data structures whose contents are customized for particular tasks.
STRUCTURE |
defines a customized data structure |
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DECLARE |
declares one or more customized data structures |
There are commands to access and display the attributes of data structures, and to work out the best formats for printing their values.
DUMP |
prints attributes of data structures and other internal information |
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DECIMALS |
sets the number of decimals for a structure, using its round-off |
GETATTRIBUTE |
accesses attributes of data structures |
LIST |
lists details of the data structures that currently exist in your program |
MINFIELDWIDTH |
calculates minimum field widths for printing data structures |