Priority

Hi,

I’m building a model of optimization logistic flows.

I have several warehouses that will supply the factories. However I want to make a restriction requiring that the first factories thou be supplied by certain warehouses and only if these warehouse are not available is that the factories are supplied by other warehouse.

I basically want to implement a hierarchy of preferences among the warehouses. Anyone have ideas on how I can implement this?


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Hi ASaLu,

What about implementing two different “warehouses” sets (preferential
and complementary warehouses) and separating the flows into two
different variables ? From there, the way to write the constraints
would depend of what is the way you have to signal that a warehouse is
available (i.e. do you use a binary variable or force a zero flow ?).

Regards
Claudio

On Wed, Feb 12, 2014 at 1:16 PM, ASaLu wrote:

Hi,

I’m building a model of optimization logistic flows.

I have several warehouses that will supply the factories. However I want to
make a restriction requiring that the first factories thou be supplied by
certain warehouses and only if these warehouse are not available is that the
factories are supplied by other warehouse.

I basically want to implement a hierarchy of preferences among the
warehouses. Anyone have ideas on how I can implement this?


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Hi,

Thanks for the reply.

It could be a great idea. I will try to implement that.
I don’t use a binary variable because the warehouses are always available. The WH aren’t available only when they are empty. I use a positive flow between warehouses and the plants.

Quinta-feira, 13 de Fevereiro de 2014 14:52:50 UTC, Claudio Delpino escreveu:

Hi ASaLu,

What about implementing two different “warehouses” sets (preferential
and complementary warehouses) and separating the flows into two
different variables ? From there, the way to write the constraints
would depend of what is the way you have to signal that a warehouse is
available (i.e. do you use a binary variable or force a zero flow ?).

Regards
Claudio

On Wed, Feb 12, 2014 at 1:16 PM, ASaLu wrote:

Hi,

I’m building a model of optimization logistic flows.

I have several warehouses that will supply the factories. However I want to
make a restriction requiring that the first factories thou be supplied by
certain warehouses and only if these warehouse are not available is that the
factories are supplied by other warehouse.

I basically want to implement a hierarchy of preferences among the
warehouses. Anyone have ideas on how I can implement this?


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Hi again,

I tried to implent what you said, but without sucess…

What was your main idea for the constraints? I assume that all warehouses are available…

Quinta-feira, 13 de Fevereiro de 2014 14:52:50 UTC, Claudio Delpino escreveu:

Hi ASaLu,

What about implementing two different “warehouses” sets (preferential
and complementary warehouses) and separating the flows into two
different variables ? From there, the way to write the constraints
would depend of what is the way you have to signal that a warehouse is
available (i.e. do you use a binary variable or force a zero flow ?).

Regards
Claudio

On Wed, Feb 12, 2014 at 1:16 PM, ASaLu wrote:

Hi,

I’m building a model of optimization logistic flows.

I have several warehouses that will supply the factories. However I want to
make a restriction requiring that the first factories thou be supplied by
certain warehouses and only if these warehouse are not available is that the
factories are supplied by other warehouse.

I basically want to implement a hierarchy of preferences among the
warehouses. Anyone have ideas on how I can implement this?


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Hi, this requires a reformulation using binary variables, personally I can’t think of an easier way.

Using LOGMIP for reformulations seems to be a good option if you don’t know how to them on your own. Let me know if you need any further help. Something along the lines of:

0 wrote:

Hi again,

I tried to implent what you said, but without sucess…

What was your main idea for the constraints? I assume that all warehouses are available…

Quinta-feira, 13 de Fevereiro de 2014 14:52:50 UTC, Claudio Delpino escreveu:

Hi ASaLu,

What about implementing two different “warehouses” sets (preferential
and complementary warehouses) and separating the flows into two
different variables ? From there, the way to write the constraints
would depend of what is the way you have to signal that a warehouse is
available (i.e. do you use a binary variable or force a zero flow ?).

Regards
Claudio

On Wed, Feb 12, 2014 at 1:16 PM, ASaLu wrote:

Hi,

I’m building a model of optimization logistic flows.

I have several warehouses that will supply the factories. However I want to
make a restriction requiring that the first factories thou be supplied by
certain warehouses and only if these warehouse are not available is that the
factories are supplied by other warehouse.

I basically want to implement a hierarchy of preferences among the
warehouses. Anyone have ideas on how I can implement this?


“gamsworld” group.
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