The reader of this manual is likely to be a member of one of two classes: those who have used the SPROGS system and those who have not; the complement of the union of the classes is not catered for herein. Members of the former class will read from the Appendices and backwards - probably never getting this far. I hope that members of the latter class - who may read from here and forwards will not object to the ugly term "User" or to the user's being referred to as "him" at one or two points in the text. What lady likes to be thought of as a user anyway?
It has been decided to emphasise any term that has a technical meaning in the context of the SMOG system and to list such terms, with "First Used" section references in Appendix 1.
Abandoning all semblance of a syntactic ethic, subroutine names are treated as imperatives (as their "Descriptives" imply) but the word "CALL" has been excluded from their definitions to improve the reading. It is hoped that the resulting text, with subroutine arguments included for consistency, will not be unpalatable nor entirely unaesthetic.
The greatest acknowledgement is due to Alan Francis whose untiring effort and meticulous attention to detail brought together many nebulous ideas (and much disjoint coding) and from them made SMOG.
Acknowledgements are also due to the following:
A W Burraston
M F Chiu
J R Gallop
F R A Hopgood
M B Kashap
P M Nelson
D Ralphs
J M Rushby
W D Shaw
R E Thomas
Production Team:
B D Barrett
J B Chamberlain
K M Gascoigne
Mathematical problems - especially those derived from physical phenomena - are often solved when one can demonstrate a functional relationship of some sort and the drawing of a graph can often give a clue to the method to employ in attempting to discover the relationship. Some part of the numerical aspect of the problem has been represented graphically.
The ability of modern computers to generate vast quantities of numbers is often an embarrassment in that a "Result" is buried in reams of paper upon which small trends and subtle effects - often unsuspected by the researcher are obscured by the sheer amount of numerical information.
The advent of computer-driven graphical peripheral devices has enabled us again to "Draw a graph" and so obtain an intuitive understanding of the behaviour of a numerical system without having to examine every entry in dozens of tables.
The computer and its graphical peripheral device, when taken out of the field of mathematical problems, can function as a powerful graphical tool in its own right. Fast type-setting and the generation of "Animated" film-sequences are both now routine tasks for the modern machine.
In order to use the computer's graphical capabilities to the full, large graphical interface packages have been developed (eg. at ACL the GROATS ALGOL and SPROGS FORTRAN systems) and these offer the user the facilities of the printing-house (font-specification, page-setting, titling, masking etc) and the film studio (zooms, pans, wipes, fades, animated effects etc) and are, in consequence, so large that the physicist, say, who wishes merely to graph the variation of temperature across a cylinder in a computational experiment must load with his program all the graphical control apparatus that the film animator might require (even though he loads very few strictly graphical routines, the size of the interface demands that many controlling instructions be loaded with them). There is obviously a need for a "minimal" graphics package and the SMOG system is an important move in that direction.