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Questions tagged [gams-math]

GAMS (General Algebraic Modeling System) is a high-level modeling system for mathematical optimization.

The General Algebraic Modeling System (GAMS) is a high-level modeling system for mathematical optimization. GAMS is designed for modeling and solving linear, nonlinear, and mixed-integer optimization problems.

References:

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Declaration of Decision variables and equations in GAMS

In my Power Control Cptimization problem I have only power vector P(I) as decision variable. However, it involves in the calculation of SINR and system total power thus, my question is: do I need to declar SINR and system total power as variables…
Meriame
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track value changement in GAMS

I have a variable named Lambda and I want to track how this value change at each iteration. I used dynamic set in GAMS and I defined the following variable: test1.l(S)=(trackvalue.l(S-1)+trackvalue.l(S))/trackvalue.l(S); I could not use this in a…
Meriame
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CPLEX Error 3019: Failure to solve MIP subproblem

I have written my Mixed-Ineteger model (MIP) in GAMS and trying to solve it with CPLEX. I encountered this error: CPLEX Error 3019: Failure to solve MIP subproblem I have 4 cores and 16 GB RAM on my PC. The optimality gap is set to 1%. After a lot…
PM0087
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How to import data from multiple excel sheets in GAMS using loops?

I want to import the data for a three-dimensional parameter p(i,j,k) that is stored in in k excel sheets but GAMS does not let me use dollar control statements in loops. Is there any way to do that using loops or other flow control statements like…
Saeed Rastegar
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sum+sum equation issue in GAMS

I defined the following equation to calculate the sum of total power consumed by the system: TotalPower.. systemPower =e= sum(J,P(J)) + sum(I,CP(I)); However, the variable systemPower gets only the result of the second sum and not both!. The…
Meriame
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write sum in gams not for all member of set

i want to write sum in gams like this: sets s/A,B,C/ R(machinery,food) . . . machinery_product..sum(Destination,x(machinery,A,Destination))=e=0 but program give me error because A and machinery arent set and they are member of set how can i write…
Milad Mirzaee
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how to define exponential expression for a set in GAMS

I want to use the expression 2^P(I) in GAMS. I tried the following: PFUN.. P(I) =e=(2**P(I)); But I always get an error 149: Uncontrolled set entered as constant. Can anyone help me to define that expression properly in GAMS? Thank you in advance.
Meriame
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initialize decision variables in GAMS in form of a set + equation gives errors

I am trying to model a problem using GAMS. I have 2 questions: 1) How to initialize the decesion value P? it supose to be in the following form P(I)/ i1 25 i2 33 / 2) I am trying to calculate SINR as in SINR(I) =e= hh(I)*P(I) /…
Meriame
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re-use the same set name multiple times in Gams

I defined a set in GAMS to represent users number. I need to use the set multiple times to define transmission power for each user, the channel quality...etc. However, I think in GAMS you can not use the name of the set for different variables, My…
Meriame
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How to extract an array from a matrix in GAMS?

i'm trying to extract an array from a matrix in GAMS. For example, i want an array that is just one column (or one row) of the matrix. Is possible to do it?
Robert Franzoi
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counting infeasible solutions in GAMS software

I want to run several mathematical models in GAMS and count the number of infeasible solutions. How should I write the condition of IF statement?
user223276
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GAMS: Why is the value of the parameter pp(ss,ii) coming out as zero?

I have written the following code below in GAMS and it may not be the best in the world but I don't see why it keeps returning the value of the parameter pp(ss,ii) as all zeros when it should be a matrix of exactly 2 ones in each row. Could you…
Nabil Kenan
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How to write a while loop in GAMS

Can anyone help me with this problem please. I want to add to i one by one and put the amount of x(i) equal to 1 in each step, so i wrote it as below but it's not working loop(i, x('0')=1; t('0')=1; while(t>m, ord(i)=ord(i)+1; …
Sepideh Gh
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Defining Probability in GAMS

Does anybody know how to define the below probability in GAMS? Z=P(x
Sepideh Gh
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Using decision variables in data definition - GAMS

I am trying to make a matrix (currently as a table) in which I have constant values and values depending on a decision variables defined later. It kind looks like this: table g(i,j) limits 1 2 1 1 0.5*x("1",j) 2 1 …
Sebastian E
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