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Equation based on set number
Posted: Sat Dec 02, 2017 4:22 am
by sinagilassi
Hi,
I defined a set and a parameter as
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Sets i /1, 2/;
Positive Variable X_V_ce(i);
one of the constraints is
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Z1(i).. X_V_ce(i) =e= X_V_ce(i+1) + ....
How it can be defined, i cannot be set i+1 !!
What can I do to add 1 or 2 to an element?
Regards
Re: Equation based on set number
Posted: Mon Dec 04, 2017 11:38 am
by Renger
Hi
This is not a problem for Gams. For i = 2, it writes the equation as
Z1(i).. X_V_ce("2") =e= 0;
If you want another formulation for this case, you could use the cardinality of set i (the number of elements):
Z1(i).. X_V_ce(i) =e= X_V_ce(i+1)$(ord(i) ne card(i) + (.....)$(ord(i) eq card(i);
Hope this answers your question
Cheers
Renger
Re: Equation based on set number
Posted: Mon Dec 04, 2017 7:25 pm
by sinagilassi
Hi Renger,
Thank you for your help
Renger wrote: ↑6 years ago
Hi
This is not a problem for Gams. For i = 2, it writes the equation as
Z1(i).. X_V_ce("2") =e= 0;
If you want another formulation for this case, you could use the cardinality of set i (the number of elements):
Z1(i).. X_V_ce(i) =e= X_V_ce(i+1)$(ord(i) ne card(i) + (.....)$(ord(i) eq card(i);
Hope this answers your question
Cheers
Renger