Search found 30 matches

by parag_patil
2 years ago
Forum: Modeling
Topic: Help in writing linear equations based on conditionality in GAMS (9 variables)
Replies: 6
Views: 4207

Help in writing linear equations based on conditionality in GAMS (9 variables)

I have tried following problem, but I could not solve it. Can you please help me in this? I have 8 binary variables : a,b,c,d,e,f,g,h I want to define a variable (x) with the help of linear equations with following conditions: x=0, if a+b+c+d+e+f+g+h≤1 x=1, if a+b+c+d+e+f+g+h>1 Further, in my proble...
by parag_patil
2 years ago
Forum: Modeling
Topic: Model a equation for following condition
Replies: 3
Views: 2384

Re: Model a equation for following condition

Thank you for your reply.

But I only want a one set of equations which will satisfy the conditions
by parag_patil
2 years ago
Forum: Modeling
Topic: Model a equation for following condition
Replies: 3
Views: 2384

Model a equation for following condition

I have three variables : A, B, C.

I want to write a linear equation such that

X = 1 if atleast 2 of A,B,C are ones.

X= 0 if only one of A,B,C is one.

A,B and C are binary (0,1).

Kindly suggest a linear equation for this.

Thank you.
by parag_patil
2 years ago
Forum: Solvers
Topic: Solving an MILP (MIP) problem within MIP problem
Replies: 1
Views: 3133

Solving an MILP (MIP) problem within MIP problem

Dear all , I have following doubt: My problem is roughly of following nature: sets it "iter" /it1*it10/ ; variables x(it) ,y(it) loop (it, MIP_problem(it) ) For each iteration above, I solve MIP problem to get x(it) and y(it) Now, I have to solve another MIP problem, which should be as fol...
by parag_patil
2 years ago
Forum: Syntax
Topic: Require a linear function
Replies: 2
Views: 2135

Re: Require a linear function

Thank you for your answer. Yes. I did the same.

It seems that linearization is more of an art and less of a science. :D
by parag_patil
2 years ago
Forum: Solvers
Topic: Getting wrong answer for an MINLP
Replies: 3
Views: 3887

Re: Getting wrong answer for an MINLP

Thank you for your answer. Indeed, I got global solution when I wrote, x.l = 3. But I did not understand two things: 1. What do you mean by 'local solver' ? I did not choose any. Meaning, I did not wrote any option. The solver is by default. --- DICOPT: Starting major iteration 1 --- DICOPT: Setting...
by parag_patil
2 years ago
Forum: Solvers
Topic: Getting wrong answer for an MINLP
Replies: 3
Views: 3887

Getting wrong answer for an MINLP

I should get x = 3 ; but I am getting x = 1 as the answer for following MINLP. Can you please tell me, why is it so? integer variable x; x.lo = 1; x.up = 3; scalar p1 /5/ p2 /10/ p3 /15/; variable cost, y; equations con1_eqn; con1_eqn.. y =e= (x-1)*(x-2)*p3 + (x-2)*(x-3)*p1 + (x-3)*(x-1)*p2; model a...
by parag_patil
2 years ago
Forum: Syntax
Topic: Require a linear function
Replies: 2
Views: 2135

Require a linear function

Dear all , I want to have a linear function , y = f(x,y1,y2,y3) The above function should give the following answers : y = y1 , if x = x1 y = y2 , if x = x2 y = y2 , if x = x3 The variable, x is an integer variable, which will only take values, x1, x2 and x3. I can do it when x is binary (0,1) as fo...
by parag_patil
2 years ago
Forum: Modeling
Topic: save variables as parameters
Replies: 2
Views: 2265

Re: save variables as parameters

Hi,

Thank you for your reply.
by parag_patil
2 years ago
Forum: Modeling
Topic: save variables as parameters
Replies: 2
Views: 2265

save variables as parameters

Dear all,
My problem setting is as follows:

1. I have set of linear equations, the variables obtained after solving these are X1,X2...,Xn and Y1,Y2...,Yn.
2. Once the above variables are obtained, these are required as parameters in the rest of the problem.

Can you please tell me how to do it?