Hi,
In most versions of Gecode's cumulative and unary constraints, you need
to provide the start, duration and end times for tasks. For the ECLiPSe
cumulative and unary constraints, you only need to provide the start and
duration times. I understand that having the end times for task allows
for more opportunities for propagation, but are they needed (or more
precisely, are the extra constraints end = start + duration needed). if
the end times are not used anywhere.
The reason I am asking is that in the ECLiPSe interface to Gecode, one
of the aim is to provide compatibility to existing ECLiPSe code, so this
means providing cumulative/unary constraints with flexible durations,
but without end times, which is what ECLiPSe has. For these constraints,
the user would have no access to the end times, but currently I still
post the extra constraints end = start + duration for each task, as the
Gecode call requires the end times, and MPG suggest that these
constraints should be posted. But when I was looking at the code
yesterday, I started to wonder if this makes sense if the user cannot
see (and so cannot post constraints that will affect) the end times. So
my question is, does it make sense to post these constraints under these
conditions?
Thanks and cheers,
Kish
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