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.
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–
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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.
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–
To view this discussion on the web visit https://groups.google.com/d/msg/gamsworld/-/vpZfqnJ1oZkJ.
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