Hello GAMS community,

I am still working on a model containing time periods (eg. years 1995-2005). The model itself is running, but not with all constraints.

I assume that the error comes from “endpoint control”, as the infeasible equations are in the last period.

In the model I am using constraints such as

constraint(t,i)… x(t,i) =l= x(t+1,i);

Can someone explain to me how endpoints are handled in GAMS? Will GAMS create an equation such as x(2005,i) =l= x(2006,i) even though 2006 is not part of the set, because I have no endpoint control? May this lead to the error?

Thanks and have a great day!

–

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If you use the option limrow= number of periods you can see in your listing all the equations that Gams will use ( with the time periods explicitly written) From there you can infer the answer to your question.

Chers

Renger

Sent from my iPhone

Am 21.11.2012 um 14:23 schrieb “JapanGo” :

Hello GAMS community,

I am still working on a model containing time periods (eg. years 1995-2005). The model itself is running, but not with all constraints.

I assume that the error comes from “endpoint control”, as the infeasible equations are in the last period.

In the model I am using constraints such as

constraint(t,i)… x(t,i) =l= x(t+1,i);

Can someone explain to me how endpoints are handled in GAMS? Will GAMS create an equation such as x(2005,i) =l= x(2006,i) even though 2006 is not part of the set, because I have no endpoint control? May this lead to the error?

Thanks and have a great day!

–

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–

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Hello Renger,

great to hear from you.

I figured that this was the problem.

Where do I put the “limrow=11” in the model? Option file? Would be great to see all the related constraints…

So far I am only able to do the endpoint control via $(ord(t) lt 11) so that non existing period 12 (=2006) is not evaluated. But I guess there is a more sophisticated way… (as indicated in the GAMS manual with lag/lead operators and subset like lastperiod or firstperiod of set period)

Am Mittwoch, 21. November 2012 14:43:22 UTC+1 schrieb Renger van Nieuwkoop:

If you use the option limrow= number of periods you can see in your listing all the equations that Gams will use ( with the time periods explicitly written) From there you can infer the answer to your question.

Chers

Renger

Sent from my iPhone

Am 21.11.2012 um 14:23 schrieb “JapanGo” :

```
Hello GAMS community,
I am still working on a model containing time periods (eg. years 1995-2005). The model itself is running, but not with all constraints.
I assume that the error comes from "endpoint control", as the infeasible equations are in the last period.
In the model I am using constraints such as
constraint(t,i).. x(t,i) =l= x(t+1,i);
Can someone explain to me how endpoints are handled in GAMS? Will GAMS create an equation such as x(2005,i) =l= x(2006,i) even though 2006 is not part of the set, because I have no endpoint control? May this lead to the error?
Thanks and have a great day!
--
To view this discussion on the web visit https://groups.google.com/d/msg/gamsworld/-/J2TTO_iUWLMJ.
To post to this group, send email to gams...@googlegroups.com.
To unsubscribe from this group, send email to gamsworld+...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/gamsworld?hl=en.
```

–

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See the manual or Mccarl

Renger

Sent from my iPhone

Am 21.11.2012 um 15:10 schrieb “JapanGo” :

Hello Renger,

great to hear from you.

I figured that this was the problem.

Where do I put the “limrow=11” in the model? Option file? Would be great to see all the related constraints…

So far I am only able to do the endpoint control via $(ord(t) lt 11) so that non existing period 12 (=2006) is not evaluated. But I guess there is a more sophisticated way… (as indicated in the GAMS manual with lag/lead operators and subset like lastperiod or firstperiod of set period)

Am Mittwoch, 21. November 2012 14:43:22 UTC+1 schrieb Renger van Nieuwkoop:

```
If you use the option limrow= number of periods you can see in your listing all the equations that Gams will use ( with the time periods explicitly written) From there you can infer the answer to your question.
Chers
Renger
Sent from my iPhone
Am 21.11.2012 um 14:23 schrieb "JapanGo" :
```

```
Hello GAMS community,
I am still working on a model containing time periods (eg. years 1995-2005). The model itself is running, but not with all constraints.
I assume that the error comes from "endpoint control", as the infeasible equations are in the last period.
In the model I am using constraints such as
constraint(t,i).. x(t,i) =l= x(t+1,i);
Can someone explain to me how endpoints are handled in GAMS? Will GAMS create an equation such as x(2005,i) =l= x(2006,i) even though 2006 is not part of the set, because I have no endpoint control? May this lead to the error?
Thanks and have a great day!
--
To view this discussion on the web visit https://groups.google.com/d/msg/gamsworld/-/J2TTO_iUWLMJ.
To post to this group, send email to gams...@googlegroups.com.
To unsubscribe from this group, send email to gamsworld+...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/gamsworld?hl=en.
```

–

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–

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