Search found 108 matches
- 6 years ago
- Forum: Modeling
- Topic: Avoiding unnecessary scanning of solution Space
- Replies: 1
- Views: 2426
Re: Avoiding unnecessary scanning of solution Space
Nice analysis! I have a warning and a suggestion to make: The warning: Have in mind that in most cases CPLEX chooses to use its propietary and secret "dynamic search"... It is (AFAIK) "impossible" (unless you stop the solver at every iteration) to really know which nodes are bein...
- 6 years ago
- Forum: Modeling
- Topic: Constraint Problem
- Replies: 2
- Views: 2737
Re: Constraint Problem
I didn't understand well... but, I want that when x11 is equal to 1 (i1=math and k1=booklet1), z11 is equal to y11 or z12 is equal to y12 or z13 is equal to y13 or z14 is equal to y14. What about something like ? Uses an auxiliary variable w(i,k,o) z(i,o)-y(k,o) =l= ( 1- w(i,k,o) ) for all o z(i,o)-...
- 6 years ago
- Forum: Syntax
- Topic: remove element from a set
- Replies: 2
- Views: 4964
Re: remove element from a set
This is totally valid GAMS: Set G /'A','B','C'/ G1 /'A','B'/ G2 /'A','C'/; display G,G1,G2; G('A')=no; display G,G1,G2; The secret, as the original error message stated, is not to use G as the domain of G1/G2 and any other symbol. This is the positive side of not having domain definitions. The negat...
- 6 years ago
- Forum: Syntax
- Topic: Set labels based on another
- Replies: 0
- Views: 2699
Set labels based on another
Hi all, I am facing a situation with model structure which I don't know what would be an elegant way to solve. In a prior version of a model I have a symbol which has dimension three: aSymbol(*,*,*) But now I want to use this symbol projected over a fourth set. aSymbol(aSet,*,*,*). This is of course...
- 6 years ago
- Forum: Syntax
- Topic: Using Indices in Model Set
- Replies: 4
- Views: 5017
- 6 years ago
- Forum: Syntax
- Topic: Error 57 with MIP code
- Replies: 1
- Views: 13669
Re: Error 57 with MIP code
Hi, checkout viewtopic.php?f=2&t=10058
- 6 years ago
- Forum: Modeling
- Topic: how to get index of variables and constraints
- Replies: 0
- Views: 3016
Re: how to get index of variables and constraints
Do you mean, Which of the elements of set time appear together with device B on a constraint or variable ?
- 6 years ago
- Forum: Syntax
- Topic: equation control
- Replies: 0
- Views: 3271
Re: equation control
Hi Yan: Check out this example, inspired with the help of the great Erwin at http://yetanothermathprogrammingconsultant.blogspot.it/2015/04/operating-on-empty-set.html $onempty set a /a1*a10/ set b(*) / /; variable x(a),dummy; equation r1,fobj; r1(a,b).. x(a)=e=1; fobj.. dummy=e=1; model c /all/; so...
- 6 years ago
- Forum: Syntax
- Topic: Writing results to Excel
- Replies: 2
- Views: 3160
Re: Writing results to Excel
Hi:
What do you want to accomplish ? Why not directly write the set IOZ to the file?
A parameter is intended to store a value mapped to each element of a set.
Good luck
What do you want to accomplish ? Why not directly write the set IOZ to the file?
A parameter is intended to store a value mapped to each element of a set.
Good luck
- 6 years ago
- Forum: Syntax
- Topic: How to find the set elements that verify a condition
- Replies: 2
- Views: 3333
Re: How to find the set elements that verify a condition
Hi Lenilein, Is TC(i,j) a parameter (fixed in an instance of a solve) or a variable ? I get from your question that you intend to use it as a variable. Be aware that if it is a variable in your model, the smin() operator would require a DNLP solver ( http://old.gams.com/latest/docs/userguides/mccarl...