Search found 87 matches

by Manassaldi
1 year ago
Forum: Syntax
Topic: Index change for constraints
Replies: 4
Views: 700

Re: Index change for constraints

Ok, you must start with the second value of i

eq(i)$(ord(i) ge 2).. T(i) =g= T(i-1);

Bye!
by Manassaldi
1 year ago
Forum: Syntax
Topic: Index change for constraints
Replies: 4
Views: 700

Re: Index change for constraints

Hi, Is T a binary or continuous variable?
Is "T(i)" greater (>) or greater than or equal (>=) than "T(i-1)" ?
Bye
by Manassaldi
1 year ago
Forum: Syntax
Topic: Question about replacing two sets
Replies: 6
Views: 1110

Re: Question about replacing two sets

I do not know if I understood correctly. Your goal is to express Data_2 in a simpler or more compact way? I hope this can help you set i /i1 * i12/ j /j1 * j3/ DATA(j,i) /j1.i1,j2.i5,j3.i9/ ; parameter Data_1(i) / i1 5 i2 3 i3 0 i4 6 i5 7 i6 9 i7 0 i8 12 i9 0 i10 2 i11 8 i12 1 / Data_2(j) ; Data_2(j...
by Manassaldi
1 year ago
Forum: Syntax
Topic: Matrix multiplication in GAMS
Replies: 1
Views: 969

Re: Matrix multiplication in GAMS

hi, the matrix dimensions must be compatible to carry out the multiplication.
Here are some examples:

Code: Select all

eq(i,j).. C(i,j) =e= sum(k,A(i,k)*B(k,j));
or

Code: Select all

eq(i,j).. C(i,j) =e=  sum((k,m)$(ord(m) eq ord(k)), A(i,k)*B(m,j) );
Bye!
by Manassaldi
1 year ago
Forum: Syntax
Topic: linearization of power function
Replies: 1
Views: 707

Re: linearization of power function

I think you should linearize the 4 possibilities and then using a binary variable to select one.
four possibilities: y^1 (linear) y^2 (non linear and convex) y^3 (non linear and convex) and y^4 (non linear and convex)
bye
by Manassaldi
1 year ago
Forum: Syntax
Topic: Syntax for sets
Replies: 2
Views: 611

Re: Syntax for sets

Is this code ok? This select the stream 4 for the mixer 2 and stream 7 for mixer 3. I hope it is useful to you Bye Set mxr number of mixers / 1*3 / Str process streams / 1*10 / imxr(mxr,str) mixer-stream (inlet) matches / 1.(1,2) , 2.(4,5), 3.(8,7) / smxr(mxr) mixer selected for linearization / 2,3 ...
by Manassaldi
1 year ago
Forum: Syntax
Topic: searching string in set
Replies: 11
Views: 1879

Re: searching string in set

In your code tac is a subset not a set... i think this is the problem
by Manassaldi
1 year ago
Forum: Syntax
Topic: searching string in set
Replies: 11
Views: 1879

Re: searching string in set

Or, if you need to use the set tid:

Code: Select all

set tid /2000*2014/;
alias(tid,tidp)
parameter
p
;
loop(tidp,
loop(tid$(ord(tid) eq card(tid) - (ord(tidp)-1)),
p=ord(tid);
display p;
););
by Manassaldi
1 year ago
Forum: Syntax
Topic: searching string in set
Replies: 11
Views: 1879

Re: searching string in set

I quickly think that it can be something like this:

set tid /2000*2014/;
parameter
p
;
loop(tid,
p=2014-(ord(tid) -1)
display p;
);
by Manassaldi
1 year ago
Forum: Syntax
Topic: searching string in set
Replies: 11
Views: 1879

Re: searching string in set

Hi, I think that order doesn't matter when you defining an equation.

set tid /2000*2014/;

equationx(tid)$condition(tid).. "an equation"