Problem description - Installations
Hello,

the problem description states that split deliveries are not allowed. Yet, I could not find any information for installations. From the solution format one could derive that split installations aren't possible as well.

The problem description also states that "[...] each machine must be installed by a technician at
the customer location." and that a penalty is incurred for each idle day. Considering a request with multiple machines of one kind, I'd interpret the above quoted line as follows: installing a request with M machines of kind K consumes M installations and a single idle day would incur M times the penalty of K. This interpretation would render the given example instance infeasible as of requests (4) and (7).

Could you clarify whether installations and penalties are per machine or per request respectively.

Kind regards and thanks in advance
bg
<hidden> - September 19, 2018 2:53 PM
3 Replies:
Dear bg,
I am not part of the organizing team, so this is no official response, but I can tell you this: The online-checker (where you upload your solution) accepts solutions with the following properties...
The number of stops for each technician is given in the instance file as the "maximum number of installations". This means that each stop at a customer is counted as *one* installation, independent from the actual number of machines. This differs from your interpretation. However, your interpretation of how the machine idle time penalty is computed appears to be correct: M times the penalty of K for each day (at least this is how the checker does it).
Hope this helps,
Kind regards,
MJG
<hidden> - September 21, 2018 2:32 PM ( 5 months ago )
Dear MJG,
thank you for that information.

Kind regards
bg
<hidden> - September 21, 2018 6:09 PM ( 5 months ago )
Dear BG,

Our apologies for the confusion about the machine installations and penalties. The answer given by MJG – thank you very much for your reply! - is correct: if a technician can do two installations per day, this means that the technician can install all machines from at most two requests per day.
Regarding the idle costs: the number of machines does indeed matter. The idle costs are calculated as follows: IDLE_MACHINE_COSTS * DAYS * NR_OF_REQUESTED_MACHINES.
We will clarify this on the website as soon as possible.

Kind regards,
VSC2019
VSC 2019 Organization - September 24, 2018 10:05 AM ( 5 months ago )