## Search found 60 matches

1 week ago
Forum: Modeling
Topic: To binary or not to binary...
Replies: 4
Views: 120

### Re: To binary or not to binary...

Hi, you can use a bounded continuous variable.
positive variable
T
;
T.lo=50;
T.up=150;

This works, except if you need that the variable take integer values.
Bye
1 month ago
Forum: Modeling
Topic: Xii >= Xij how to code in GAMS
Replies: 2
Views: 102

### Re: Xii >= Xij how to code in GAMS

Hi, it's simple

set i warehouse /1*3/;
alias(i,j);

eq(i,j)\$(ord(i) ne ord(j)).. X(i,i) =g= X(i,j);

Bye
2 months ago
Forum: Syntax
Topic: kind request: Setting two variables equal in GAMS
Replies: 1
Views: 115

### Re: kind request: Setting two variables equal in GAMS

Hi,
what is J, K, RJ and KR?
Can you explain what each set means?

An alternative can be:

eq(J,K,RJ,KR)\$(sameas(J,RJ) and sameas(K,KR)).. FlowMSAsMEN(J,K) =E= FlowMSAsREG(RJ,KR);

Bye
2 months ago
Forum: Syntax
Topic: logical equations & binary variables
Replies: 13
Views: 986

### Re: logical equations & binary variables

Hi, I think you can try a simple big-M reformulation. I assume that "HS(j)" is continuous and positive. The new variable TWC_HS(j) correspond to TWC(j)*HS(j) x(j) is a binary variable: x(j)=1 if HS(j) >=1000. x(j)=0 if HS(j) < 1000 eq1(j).. HS(j) =g= 1000*x(j); eq2(j).. TWC_HS(j) =g= 3.21*HS(j) - 3....
4 months ago
Forum: Modeling
Topic: converting an integer variable into a binary variable
Replies: 2
Views: 308

### Re: converting an integer variable into a binary variable

Hi, try these equations:

eq.. X =l= M*Y
eq.. X =g= Y

M is a parameter and the upper bound of X

If Y =1
X =l= M
X =g= 1

if Y = 0
X =l= 0
X =g= 0

Bye!
5 months ago
Forum: Syntax
Topic: logical equations & binary variables
Replies: 13
Views: 986

### Re: logical equations & binary variables

Hi, To avoid taking the first element, in my opinion, it is preferable to use this code:

e_T_pi(i)\$(ord(i) gt 1) .. T_pi(i)*(m_rc_pb(i)+m_ts_pb(i)) =e= (m_rc_pb(i)*T_ro + m_ts_pb(i)*T_to(i));

Bye!
5 months ago
Forum: Syntax
Topic: logical equations & binary variables
Replies: 13
Views: 986

### Re: logical equations & binary variables

Hi, In another post I suggested this equation

e_T_pi(i+1) .. T_pi(i+1)*(m_rc_pb(i+1)+m_ts_pb(i+1)) =e= (m_rc_pb(i+1)*T_ro + m_ts_pb(i+1)*T_to(i+1));
5 months ago
Forum: Syntax
Topic: logical equations & binary variables
Replies: 13
Views: 986

### Re: logical equations & binary variables

Hi, the equation listing and column Listing shows the value on the initial point, not in the solution. The equations are fine.
You should review the SolEQU and SolVAR section.
Bye!
5 months ago
Forum: Syntax
Topic: logical equations & binary variables
Replies: 13
Views: 986

### Re: logical equations & binary variables

Hi, It's similar

eq1.. m =g= m.lo*(1-x);
eq2.. m =l= m.up*(1-x)

Bye!
5 months ago
Forum: Syntax
Topic: logical equations & binary variables
Replies: 13
Views: 986

### Re: logical equations & binary variables

Hi, try these equations

eq1.. m =g= m.lo*x;
eq2.. m =l= m.up*x;

m.lo (lower bound)
m.up (upper bound)

if x=1
m greater than m.lo*1;
m lower than m.up*1
if x=0
m greater than m.lo*0;
m lower than m.up*0;
so, m = 0

Bye!