In this column, we try to keep you up to date with the EMME/2 development work that is currently going on. We will only tell you about the things that, at the time of writing, have already been implemented and are now in the phase of being tested. While it might still be a while before these new features will be distributed as part of a regular EMME/2 release, the list below should give you an indication on where our priorities are and on what to expect in the next release. Detailed technical discussions of these features will be given when the new release is officially announced.
A lot of activity is aimed at making EMME/2 more colorful. The color index approach, discussed in the last issue, has now been integrated into modules 6.22 and 2.13. The network editor, module 2.12, has been modified to use different colors to make network modifications on the work sheet stand out more clearly. When comparing histograms with module 3.16, the two histograms are now displayed in different colors, as are the legend on the right hand margin and and the x-axis annotations indicating means and standard deviations of the 2 histograms. The color of the hatching between the histograms corresponds to the color of the higher valued histogram.
A new switch, no. 11, has been defined. Depending on its state, only those batch input cards on which an error is detected are echoed on the report that is generated. This produces much shorter reports and makes tracing of the erroneous cards much easier. So far, the two modules that produce the most voluminous output, 2.11 and 3.11, have implemented this switch.
The handling of algebraic expressions has been improved. The evaluation
priorities have been adjusted so that now less parentheses will be required.
Also, the symbolic forms of the comparison operators ("<",">","==", ...)
are now allowed in expressions. The new intrinsic functions put() and
get() allow efficient reuse of common subexpressions.
Much work has also been done to make data bases portable between systems of different size. To achieve this goal, the number of transit lines, the length of the demarcation sets and the size of the log book may now be chosen by the user at the time of data base creation. With these changes, data bases may be run on any size system that is large enough, independent of the size of the system on which it was created originally. Thus, it is now possible for a user to upgrade his system to a bigger size, without any need to redo the existing data bases.
Module 2.15, "Plot shortest paths on base network", has been enhanced to newly allow also visualizing shortest path trees and forests to nodes (as opposed to from nodes). The new menu command "dim" displays the dimensions of the current data base. Default speed, cost and energy coefficients can now go up to 999.99 (instead of 99.99). The maximum data base size is no longer limited to 64 Megabytes; the new limit is set to 1 Gigabyte, which should be plenty for even the largest applications.