Search found 441 matches

by Renger
1 day ago
Forum: Syntax
Topic: Is there a way for GAMS interruption and re-run from where it lasted?
Replies: 5
Views: 75

Re: Is there a way for GAMS interruption and re-run from where it lasted?

Hi
You might have a look at savepoint and split your models in two files.
Cheers
Renger
by Renger
1 day ago
Forum: Archive Google Group
Topic: How to maximise a non-scalar objective?
Replies: 2
Views: 33

Re: How to maximise a non-scalar objective?

Hi
If you want to solve for every combination of i and t (ixt solves), you might wright a scalar function and scalar equations and loop your solve over i and t. Otherwise, it doesn't make much sense.
Cheers
Renger
by Renger
2 days ago
Forum: API
Topic: pySetup=0
Replies: 1
Views: 45

pySetup=0

Hi
Back to the discussion on setting up python using another Python distribution.
In the documentation/discussions it is said that one should use "pySetup=0" but it is not clear how to use this: In my code? When setting up python for Gams?
Any help would be appreciated.
Cheers
Renger
by Renger
2 days ago
Forum: Solvers
Topic: Couenne- NLP heuristic: time limit reached
Replies: 2
Views: 63

Re: Couenne- NLP heuristic: time limit reached

Hi Lily According to the documentation you can use reslim (in seconds). "GAMS/Couenne understands currently the following GAMS parameters: reslim (time limit), nodlim (node limit), cutoff, optca (absolute gap tolerance), and optcr (relative gap tolerance). Further, the option threads can be used to ...
by Renger
2 days ago
Forum: Syntax
Topic: Providing initial solution and reoptimizing
Replies: 3
Views: 82

Re: Providing initial solution and reoptimizing

Hi Nikou

You could do this as follows:

Code: Select all

MODEL MyModel /ALL/;
SOLVE MyModel USING MILP MAXIMIZING Z ;

model MyModel2 /... all equations without eq2/;
SOLVE MyModel2 USING MILP MAXIMIZING Z ;
Gams will automatically use the solution from your first solve for the next solve.

Cheers
Renger
by Renger
3 days ago
Forum: Syntax
Topic: Sum with index as a function
Replies: 5
Views: 95

Re: Sum with index as a function

Hi Here is a little example that you can use to implement your equation. I assume that a is a parameter. (you can't use a variable in a $-condition in an equation) set j /1*20/, i /1*20/; parameter a /-2/, b(i), x(j); x(j) = uniform(1,10); b(i) = Sum (j$(j.val = i.val - a + 1) , x(j)); display b, x;...
by Renger
4 days ago
Forum: Syntax
Topic: replicas model
Replies: 2
Views: 65

Re: replicas model

Hi Diana
You can use a loop to do this:

Code: Select all

set l Loops /l1*l20000/;

parameter results(l,*);
loop(l, 
    assign the random variable
    solve your model
    save the results in results(l,*)  results(l,"MyResult") = X.L;
Cheers
Renger
by Renger
4 days ago
Forum: Syntax
Topic: creation of vectors from normal distribution
Replies: 3
Views: 96

Re: creation of vectors from normal distribution

Hi Diana
If I understand you correctly, the table t contains several variables and you want to use the mean of these values for j.
You can then just sum over p and divide by the rank of p (which gives you the number of elements of p):

Code: Select all

a(i,j)= normal(x(j,i),sum(p,t(j,p))/rank(p));
Cheers
Renger
by Renger
5 days ago
Forum: Syntax
Topic: sets in gams
Replies: 1
Views: 45

Re: sets in gams

Hi You can either use card in the equation X(i,j,k)$(ord(k) = card(k)) = ... or use a dynamic set: SET k /1 * 3/, klast(k) ; klast(k)$(ord(k) = card(k))= YES; X(i,j,klast) = .... In both cases, you can change the cardinality of the set and this will be reflected in your assignment of X. Cheers Renger
by Renger
5 days ago
Forum: Archive Google Group
Topic: MCP solver Infeasible
Replies: 6
Views: 92

Re: MCP solver Infeasible

Hi

You mean that L(t) is exogenous in every period like L(t) = (1+n)**t.val * L0?
Cheers
Renger