Bugs + Fixes

Fortunately there have not been many, nor very serious bug reports since we last reported about bugs and fixes in April 1993. Since then, three new minor release updates, 6.3, 6.4 and 6.5, have been made available.

Here are brief descriptions of some of the bugs that were fixed in these recent updates:

• When using the new editing possibilities of module 2.11 for adding and deleting nodes, problems could occur when all outgoing links were deleted and then new links added again to the same node. Also, in the same module, adding or deleting nodes caused the loss of the values of extra node attributes.
• A bug was found in option 2 of module 2.12: when initializing only the link table, leaving the node table unchanged, module 2.12 would abort when trying to add links to the same scenario later on.
• In multiclass auto assignments, when performing an additional options assignment using length as additional link attribute, wrong distance values were used for computing the additional path attribute during iteration 0.
• When analyzing individual transit trips with module 5.35, no paths were found for trips to and from the centroid with the lowest node number. All applications which use regular nodes for access and egress -which is the normal case- are not affected by this bug. This might explain why this bug went undetected ever since the introduction of module 5.35 in Release 4.
• On DOS systems only, due to a change in the error trapping behavior of the compiler, the execution of a module was aborted when an invalid floating point operand was detected. As such invalid operands do not occur under normal circumstances, but only as secondary effects after overflow or division-by-zero, this bug only occurs as side effect of data coding errors, and disappears as soon as the incorrect data is corrected.

All these problems have been corrected in release update 6.5. If any of the above mentioned bug are causing undue problems in your application, please contact INRO for the latest release update kit for your type of installation. If the version of EMME/2 which you use is already at update level 6.3 or 6.4, please check the supplementary release notes to find out which of the above errors are already corrected in your system.