How to avoid stopping the solver if no feasible solution has been found.

Archiver · October 22, 2012, 11:45pm

Hi

I am testing a model that more than 95% of the times gives an optimal or almost optimal solution within 90 seconds. So, I have used the command reslim=90; Usually if the solution is not optimal is a good enough starting solution for a subsequent problem.

However, eventually, in rare occasions it doesnâ€™t find a single feasible solution within that time.

Is it possible to indicate gams that it must stop at 90 seconds but only if it has found at least 1 feasible solution? If is not possible, would it be enough using the savpoint and restart options?

Thanks

Jose

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Archiver · October 23, 2012, 11:34am

Hi JosÃ©

You could use the model status information for a condition like if (status = infeasible, change the reslim to whatever you like, solve the model again);

Be careful, however to have some kind of stopping condition, if the model is really infeasibleâ€¦

You can get the model status by defining a parameter that stores the value:

Parameter modelstatus;

modelstatus = mymodel.modelstat;

(where mymodel is the name of the model).

If modelstatus = 6,

â€¦.

);

modelstat 6 means Solver terminated early and model was infeasible

For more information on this in McCarls User Guide (page 485, 711,712)

Cheers

Renger

Von: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] Im Auftrag von JosÃ© Miguel Quesada PÃ©rez
Gesendet: Monday, October 22, 2012 11:46 PM
An: gamsworld@googlegroups.com
Betreff: How to avoid stopping the solver if no feasible solution has been found.

Hi

I am testing a model that more than 95% of the times gives an optimal or almost optimal solution within 90 seconds. So, I have used the command reslim=90; Usually if the solution is not optimal is a good enough starting solution for a subsequent problem.

However, eventually, in rare occasions it doesnâ€™t find a single feasible solution within that time.

Is it possible to indicate gams that it must stop at 90 seconds but only if it has found at least 1 feasible solution? If is not possible, would it be enough using the savpoint and restart options?

Thanks

Jose

–
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Archiver · October 23, 2012, 7:36pm

Thank you very much Renger.

Iâ€™ll try to do it in that way. Iâ€™ll take care of not letting it run infinitely in case the problem is really infeasible.

Best Regards

JosÃ©

From: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] On Behalf Of Renger van Nieuwkoop
Sent: martes, 23 de octubre de 2012 04:35 a.m.
To: gamsworld@googlegroups.com
Subject: AW: How to avoid stopping the solver if no feasible solution has been found.

Hi JosÃ©

You could use the model status information for a condition like if (status = infeasible, change the reslim to whatever you like, solve the model again);

Be careful, however to have some kind of stopping condition, if the model is really infeasibleâ€¦

You can get the model status by defining a parameter that stores the value:

Parameter modelstatus;

modelstatus = mymodel.modelstat;

(where mymodel is the name of the model).

If modelstatus = 6,

â€¦.

);

modelstat 6 means Solver terminated early and model was infeasible

For more information on this in McCarls User Guide (page 485, 711,712)

Cheers

Renger

Von: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] Im Auftrag von JosÃ© Miguel Quesada PÃ©rez
Gesendet: Monday, October 22, 2012 11:46 PM
An: gamsworld@googlegroups.com
Betreff: How to avoid stopping the solver if no feasible solution has been found.

Hi

I am testing a model that more than 95% of the times gives an optimal or almost optimal solution within 90 seconds. So, I have used the command reslim=90; Usually if the solution is not optimal is a good enough starting solution for a subsequent problem.

However, eventually, in rare occasions it doesnâ€™t find a single feasible solution within that time.

Is it possible to indicate gams that it must stop at 90 seconds but only if it has found at least 1 feasible solution? If is not possible, would it be enough using the savpoint and restart options?

Thanks

Jose

–
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Archiver · October 23, 2012, 11:32pm

Hi Renger

I tryed it and it Works more or less, I mean, it works but begins solving again from scratchâ€¦I am using CPlex, how can the model solve again but from where it let the work previously?

Regards

MC. JosÃ© Miguel Quesada PÃ©rez
Departamento de IngenierÃa Industrial

TecnolÃ³gico de Monterrey, Campus QuerÃ©taro

52 (442) 238 3100 Ext: 6349

Fax: (442) 238 32 70

Enlace intercampus: 8 0 776 6349

cid:image002.png@01CD2C58.E47E9EA0

El contenido de este mensaje de datos no se considera oferta, propuesta o acuerdo, sino hasta que sea confirmado en documento por escrito que contenga la firma autÃ³grafa del apoderado legal del ITESM. El contenido de este mensaje de datos es confidencial y se entiende dirigido y para uso exclusivo del destinatario, por lo que no podrÃ¡ distribuirse y/o difundirse por ningÃºn medio sin la previa autorizaciÃ³n del emisor original. Si usted no es el destinatario, se le prohÃbe su utilizaciÃ³n total o parcial para cualquier fin.

The content of this data transmission is not considered as an offer, proposal, understanding, or agreement unless it is confirmed in a document signed by a legal representative of ITESM. The content of this data transmission is confidential and it is intended to be delivered only to the addresses, therefore, it shall not be distributed and/or disclosed through any mean without the original sender’s previous authorization. If you are not the addressee you are forbidden to use it, either totally or partially, for any purpose.

From: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] On Behalf Of Renger van Nieuwkoop
Sent: martes, 23 de octubre de 2012 04:35 a.m.
To: gamsworld@googlegroups.com
Subject: AW: How to avoid stopping the solver if no feasible solution has been found.

Hi JosÃ©

You could use the model status information for a condition like if (status = infeasible, change the reslim to whatever you like, solve the model again);

Be careful, however to have some kind of stopping condition, if the model is really infeasibleâ€¦

You can get the model status by defining a parameter that stores the value:

Parameter modelstatus;

modelstatus = mymodel.modelstat;

(where mymodel is the name of the model).

If modelstatus = 6,

â€¦.

);

modelstat 6 means Solver terminated early and model was infeasible

For more information on this in McCarls User Guide (page 485, 711,712)

Cheers

Renger

Von: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] Im Auftrag von JosÃ© Miguel Quesada PÃ©rez
Gesendet: Monday, October 22, 2012 11:46 PM
An: gamsworld@googlegroups.com
Betreff: How to avoid stopping the solver if no feasible solution has been found.

Hi

I am testing a model that more than 95% of the times gives an optimal or almost optimal solution within 90 seconds. So, I have used the command reslim=90; Usually if the solution is not optimal is a good enough starting solution for a subsequent problem.

However, eventually, in rare occasions it doesnâ€™t find a single feasible solution within that time.

Is it possible to indicate gams that it must stop at 90 seconds but only if it has found at least 1 feasible solution? If is not possible, would it be enough using the savpoint and restart options?

Thanks

Jose

–
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Archiver · October 24, 2012, 9:12am

Use savepoint ( see mccarls guide)
Renger

Sent from my iPhone

On 24.10.2012, at 09:11, “JosÃ© Miguel Quesada PÃ©rez” wrote:

Hi Renger

I tryed it and it Works more or less, I mean, it works but begins solving again from scratchâ€¦I am using CPlex, how can the model solve again but from where it let the work previously?

Regards

MC. JosÃ© Miguel Quesada PÃ©rez
Departamento de IngenierÃa Industrial

TecnolÃ³gico de Monterrey, Campus QuerÃ©taro

52 (442) 238 3100 Ext: 6349

Fax: (442) 238 32 70

Enlace intercampus: 8 0 776 6349

El contenido de este mensaje de datos no se considera oferta, propuesta o acuerdo, sino hasta que sea confirmado en documento por escrito que contenga la firma autÃ³grafa del apoderado legal del ITESM. El contenido de este mensaje de datos es confidencial y se entiende dirigido y para uso exclusivo del destinatario, por lo que no podrÃ¡ distribuirse y/o difundirse por ningÃºn medio sin la previa autorizaciÃ³n del emisor original. Si usted no es el destinatario, se le prohÃbe su utilizaciÃ³n total o parcial para cualquier fin.

The content of this data transmission is not considered as an offer, proposal, understanding, or agreement unless it is confirmed in a document signed by a legal representative of ITESM. The content of this data transmission is confidential and it is intended to be delivered only to the addresses, therefore, it shall not be distributed and/or disclosed through any mean without the original sender’s previous authorization. If you are not the addressee you are forbidden to use it, either totally or partially, for any purpose.

From: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] On Behalf Of Renger van Nieuwkoop
Sent: martes, 23 de octubre de 2012 04:35 a.m.
To: gamsworld@googlegroups.com
Subject: AW: How to avoid stopping the solver if no feasible solution has been found.

Hi JosÃ©

You could use the model status information for a condition like if (status = infeasible, change the reslim to whatever you like, solve the model again);

Be careful, however to have some kind of stopping condition, if the model is really infeasibleâ€¦

You can get the model status by defining a parameter that stores the value:

Parameter modelstatus;

modelstatus = mymodel.modelstat;

(where mymodel is the name of the model).

If modelstatus = 6,

â€¦.

);

modelstat 6 means Solver terminated early and model was infeasible

For more information on this in McCarls User Guide (page 485, 711,712)

Cheers

Renger

Von: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] Im Auftrag von JosÃ© Miguel Quesada PÃ©rez
Gesendet: Monday, October 22, 2012 11:46 PM
An: gamsworld@googlegroups.com
Betreff: How to avoid stopping the solver if no feasible solution has been found.

Hi

I am testing a model that more than 95% of the times gives an optimal or almost optimal solution within 90 seconds. So, I have used the command reslim=90; Usually if the solution is not optimal is a good enough starting solution for a subsequent problem.

However, eventually, in rare occasions it doesnâ€™t find a single feasible solution within that time.

Is it possible to indicate gams that it must stop at 90 seconds but only if it has found at least 1 feasible solution? If is not possible, would it be enough using the savpoint and restart options?

Thanks

Jose

–
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To unsubscribe from this group, send email to gamsworld+unsubscribe@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/gamsworld?hl=en.

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Archiver · October 25, 2012, 6:54pm

Thank you again Renger, Iâ€™ll test it.

52 (442) 238 3100 Ext: 6349

Fax: (442) 238 32 70

Enlace intercampus: 8 0 776 6349

cid:image002.png@01CD2C58.E47E9EA0

El contenido de este mensaje de datos no se considera oferta, propuesta o acuerdo, sino hasta que sea confirmado en documento por escrito que contenga la firma autÃ³grafa del apoderado legal del ITESM. El contenido de este mensaje de datos es confidencial y se entiende dirigido y para uso exclusivo del destinatario, por lo que no podrÃ¡ distribuirse y/o difundirse por ningÃºn medio sin la previa autorizaciÃ³n del emisor original. Si usted no es el destinatario, se le prohÃbe su utilizaciÃ³n total o parcial para cualquier fin.

The content of this data transmission is not considered as an offer, proposal, understanding, or agreement unless it is confirmed in a document signed by a legal representative of ITESM. The content of this data transmission is confidential and it is intended to be delivered only to the addresses, therefore, it shall not be distributed and/or disclosed through any mean without the original sender’s previous authorization. If you are not the addressee you are forbidden to use it, either totally or partially, for any purpose.

From: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] On Behalf Of Renger van Nieuwkoop
Sent: miÃ©rcoles, 24 de octubre de 2012 02:13 a.m.
To:
Subject: Re: How to avoid stopping the solver if no feasible solution has been found.

Use savepoint ( see mccarls guide)

Renger

Hi Renger

I tryed it and it Works more or less, I mean, it works but begins solving again from scratchâ€¦I am using CPlex, how can the model solve again but from where it let the work previously?

52 (442) 238 3100 Ext: 6349

Fax: (442) 238 32 70

Enlace intercampus: 8 0 776 6349

El contenido de este mensaje de datos no se considera oferta, propuesta o acuerdo, sino hasta que sea confirmado en documento por escrito que contenga la firma autÃ³grafa del apoderado legal del ITESM. El contenido de este mensaje de datos es confidencial y se entiende dirigido y para uso exclusivo del destinatario, por lo que no podrÃ¡ distribuirse y/o difundirse por ningÃºn medio sin la previa autorizaciÃ³n del emisor original. Si usted no es el destinatario, se le prohÃbe su utilizaciÃ³n total o parcial para cualquier fin.

The content of this data transmission is not considered as an offer, proposal, understanding, or agreement unless it is confirmed in a document signed by a legal representative of ITESM. The content of this data transmission is confidential and it is intended to be delivered only to the addresses, therefore, it shall not be distributed and/or disclosed through any mean without the original sender’s previous authorization. If you are not the addressee you are forbidden to use it, either totally or partially, for any purpose.

From: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] On Behalf Of Renger van Nieuwkoop
Sent: martes, 23 de octubre de 2012 04:35 a.m.
To: gamsworld@googlegroups.com
Subject: AW: How to avoid stopping the solver if no feasible solution has been found.

Hi JosÃ©

You could use the model status information for a condition like if (status = infeasible, change the reslim to whatever you like, solve the model again);

Be careful, however to have some kind of stopping condition, if the model is really infeasibleâ€¦

You can get the model status by defining a parameter that stores the value:

Parameter modelstatus;

modelstatus = mymodel.modelstat;

(where mymodel is the name of the model).

If modelstatus = 6,

â€¦.

);

modelstat 6 means Solver terminated early and model was infeasible

For more information on this in McCarls User Guide (page 485, 711,712)

Cheers

Renger

Von: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] Im Auftrag von JosÃ© Miguel Quesada PÃ©rez
Gesendet: Monday, October 22, 2012 11:46 PM
An: gamsworld@googlegroups.com
Betreff: How to avoid stopping the solver if no feasible solution has been found.

Hi

I am testing a model that more than 95% of the times gives an optimal or almost optimal solution within 90 seconds. So, I have used the command reslim=90; Usually if the solution is not optimal is a good enough starting solution for a subsequent problem.

However, eventually, in rare occasions it doesnâ€™t find a single feasible solution within that time.

Is it possible to indicate gams that it must stop at 90 seconds but only if it has found at least 1 feasible solution? If is not possible, would it be enough using the savpoint and restart options?

Thanks

Jose

–
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