Re: [Help-glpk] Building a Contract Scenario

[Andrew Makhorin]

On Wed, 2017-08-02 at 16:11 -0400, Peter Quincy Ng wrote:
> Hello,
> Thank you for your previous response it was quite helpful. I am having
> trouble with another problem and wasn't able to find this in the GLPK
> GNU manual.
> 
> So, I have a contract scenario where I want to start and end contracts
> to meet demand. My problem is that I want to list the long-term
> contracts so that meet demand over several days, but cannot be started
> on certain days, so the value for long-term will be zero.
> 
> So I have this dataset:
> 
> set DATES :=
> 
> 4.01
> 4.02
> 4.03
> 4.04
> 4.05
> 4.06
> 4.07
> 4.08
> 
> And have the following demand:
> 
> param NumDemand :=
> 
> 4.01  0
> 
> 4.02  1
> 
> 4.03  5
> 
> 4.04  2
> 
> 4.05  0
> 
> 4.06  1
> 
> 4.07  9
> 
> 4.08  12
> 
> So I have a constraint where short-term contracts and long-term
> contracts must meet demand so:
> 
> ShortTerm + LongTerm >= NumDemand
> 
> But long terms can only start on 4.03 to 4.06, so I need to put the
> values for 4.01, 4.02, 4.07 and 4.08 when I optimize.

I think you need to define two sets of dates: one for long-term and
other for short-term contracts, and then use them as indexing sets.

[Please post your questions to the help-glpk list, not to me.]

> 
> I hope that makes sense,
> 
> Thanks,
> Peter
>