MX is a flexible interactive matrix manipulation program which incorporates virtually all matrix operations required by SATURN users. It includes options to build matrices, change them (e.g. by factoring) and analyse them. The flexibility means, for example, that users can carry out their own trip matrix demand model procedures involving e.g., trip distribution (constrained or otherwise), modal split, park and ride etc using the facilities within MX, even if those procedures are not explicitly included within MX (as some are; see 10.20).
Although MX has been constructed as a perfectly general matrix manipulation program clearly its primary use will be based on SATURN and transport planning applications. Indeed the vast majority of matrices which MX handles will be origin-destination trip matrices. This is very often reflected in the language used in the documentation; for example “row” and “column” are used interchangeably with “origin” and “destination” and sometimes cell values are referred to explicitly as “trips”, e.g. when discussing distribution models. Equally “O-D” and “I-J” will be used interchangeably when referring to individual cell locations.
MX includes all the facilities previously provided in earlier SATURN versions by the separate programs M1 through M7 plus many new ones. The original historical program names tend to live on within, e.g., batch files names and some internal options within MX. See 10.9.2, 10.20 and Appendix W.
MX operates essentially on a single “internal” matrix stored in RAM although operations involving up to 10 “external” matrices are also permitted. More details are given in 10.3.
In operational terms MX is an interactive menu-based program, largely but not exclusively text-based (see 19.5), and the general principles outlined in Section 19.2 apply.