GAMS World Forum

Hi Sue
Could you write out examples of the equation you want in point 1. It is not clear to me.
Point 2: You could use a set defining which elements you don't want (e.g. set src(nt) /n3/; and write the equation q4(nt)$(not src(nt)).

Cheers
Renger

Hi
The problem is that you use both i and j in two different ways: as an index for the equation and as summation index.
You need an alias:

Code: Select all

alias(i,ai), (j,aj);
eq6(i,j).. sum(ai, Q(ai,j)) =e= sum(aj, Q(i,aj));

This resolves the confusion on what to do with "i" and "j".
Cheers
Renger

Hi
I would do all the computation in Gams, save the results in gdx and use R to do the analysis and graphs.
You can generate random numbers in Gams and use loops (for each parameter you are changing one loop).
See also this post.

Cheers
Renger

Hi
It would be easier if you would paste your code in your post (use the button </> so it is formatted correctly).
Cheers
Renger

Hi You could use a nested loop for every parameter you want to do sensitivity analysis. Assume you use P1 and P2 for this and assume they can take the following three values 0.005, 0.01, and 0.0015. set n /1*3/ Set for the number of values; parameter P1s(n) Possible values P1, P2s(n) Possible values...

Hi YOu could do as follows: alias(i,ai), (j,aj); parameter frequency(i,j,ai,aj) Frequency of solutions; frequency(i,j,ai,aj)$(ord(i) = 1) = sum(k$(not sameas(i,ai) and not sameas(j,aj)), report(k,i,j)*report(k,ai,aj)) ; display frequency; this gives you index = 1 3 4 1.2 1.000 3.000 2.2 4.000 2.000 ...

Hi Thanks for the clarification. I think you can use mappings. These are multidimensional sets that assign elements of one set to another set. Afterwards you can use the mappings in your equations and assignments. Take a look here mappings . set P index set of products /p1*p3 L index set of producti...

Hi I am setting up my new laptop. I have the following questions with regard to Gams-Python (Gams 30'Beta): When I try to install the Python 3.7 with "python setup.py install", in the API3.7 directory, I get the error message "Fatal error: Trying to install GAMS Python API 3.7 using Python. I have t...

Hi
Your first figure isn't displayed correctly, so it is hard to answer your question.
Cheers
Renger

Hi
I assume that the problem is in the c' not equal to c. You can do this with an if condition:

Code: Select all


equation eq_sum(c,s)
alias(c, cc);

eq_sum(c,sc)
  ....   - sum(cc$(not sameas(cc,c), ...

Cheers
Renger

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