GAMS World Forum

Hi Harry
There are some nice models in the GAMS model library. For example, SROUTE, TRAFFIC. I would have a close look at the techniques they use (especially the mappings) to write down a network.
Cheers
Renger

Hi I do not understand what you are trying to achieve. The code you show is obviously not doing anything as d(i,j), a parameter, should, during the solve, change according to values of Y, a variable. d(i,j) should, therefore, be a variable. Perhaps you are looking for an iterative (loop) for doing t...

Hi Your error comes from adding the same set elements twice (line 40 and line 42 are equal. 40 HK.SG.1.HK1.JK1.sr1, 41 HK.SG.1.JK1.SG1.sr1, 42 HK.SG.1.HK1.JK1.sr1, ... This is not the first mistake in your code. Always correct the earlier error before you proceed with the following ones, but the lat...

Hi If you have a very urgent error, you should at least provide the complete code that produces the error, otherwise it will be just guessing. So at least provide the code inclusive of the part that produces the error. Have a look at the "Rules" of this forum ( https://forum.gamsworld.org/...

Hi
You just make one constraint and multiply the number 20-part on both sides by(x(i,jm,) and the 21-part by (1 - x(i,j,m)) .
If x(i,j,m) = 1, only the 20-parts are used, if x(i,jm) = 0, only the 21-parts will be used.
CHeers
Renger

Hi Here is a small example with uniformly distributed random date set i /r1*r3/, j /c1*c3/, iter /1*3/; parameter randval(i,j) Random values, randvalloop(iter, i,j) Store the random values; * Set uniform random values between 1 and 10 * and set the seed so we can reproduce the results $set seed 1234...

Hi You use the wrong index for investments: in your table, it is indexed by "SI", and in your model by "S-I". - You should force GAMS to check your table on errors like these by defining SAM over the set of all SAM elements. E.g.: set ac All SAM elements /a_min, apetroil, a_ael, ...

Hi I only use the f loop because you use K(i,t) in an equation with the additional index f. i and t are on both sides of the assignment but f is missing on the right: loop(f, eq_net9("K", i,f,t) = K.L(i,t); ); If K was also defined over f, you don't have to use a loop to assign values and ...

Hi You defined the variables over i, j and t, so if you solve the model for a smaller subset, the variables that are not part of the subset aren't changed and keep the values of the previous solve. If you add some lines where you initialize all the variable with EPS loop(... loop(... loop(.. x.L ( i...

just redefine the parameter as and adjust the export command as follows: This will correct the order and you will have the output according to equations.
CHeers
Renger