Re: [Help-glpk] Ordered bin packing

[Dmitri Goutnik]

Hi Jeff,

Thanks, yes that would be preferable packing. My goal is to pack items as "tightly" as possible while preserving even (within some predefined margin) weight distribution between bins.

Best regards,

Dmitri

On 27/01/2013, at 13:40, Jeffrey Kantor <address@hidden> wrote:

Hi Dmitri,

This could be done through the objective function. But before going there, I'm wondering a bit

about the solution you're showing for your example.  Wouldn't you want move item 7 from Bin 3 to Bin 2 to meet your primary objective?

Jeff

On Sun, Jan 27, 2013 at 1:34 PM, Dmitri Goutnik <address@hidden> wrote:

Hello everyone,

I modified bpp.mod to pack items in predefined number of bins of unlimited capacity so that weight is (approximately) evenly distributed between bins. In addition to weight, each item has an "order" or "position". Is there a way to write an additional model constraint so that items are preferably packed in compact order, e.g. items with sequential positions should go to the the same container? For example, for this solution:

Bin 1: total weight 110
        item 1 (40)
        item 4 (70) <--

Bin 2: total weight 90
        item 5 (50)
        item 6 (40)

Bin 3: total weight 130
        item 2 (60) -->
        item 3 (30)
        item 7 (15)
        item 8 (25)

is there a way to add such constraint so item 2 would preferably be packed to bin 1?

Thanks,
Dmitri
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