Search found 81 matches

by Manassaldi
6 days ago
Forum: Syntax
Topic: logical equations & binary variables
Replies: 16
Views: 1894

Re: logical equations & binary variables

Hi, if p (n) is a parameter, I think it is better to reformulate the intervals definition: if th >= p(n) then a(n) =0; else if th < p(n) and th >= p(n) * 10^-.5 then a(n) = .2; else if th < p(n)*10^-.5 and th >= p(n) * 10^-1 then a(n) = .4; else if th < p(n)*10^-1 and th >= p(n) * 10^-1.5 then a(n) ...
by Manassaldi
1 week ago
Forum: Tools
Topic: Generate an array of random numbers
Replies: 6
Views: 124

Re: Generate an array of random numbers

I did not know the shuffle option. Thanks for sharing dirkse!
by Manassaldi
2 weeks ago
Forum: Tools
Topic: Generate an array of random numbers
Replies: 6
Views: 124

Re: Generate an array of random numbers

Hi dirkse, i like your compact implementation.
I tested your code but sometimes I got less than seven items with a value of 1 and sometimes more.
i'm right?
by Manassaldi
2 weeks ago
Forum: Tools
Topic: Generate an array of random numbers
Replies: 6
Views: 124

Re: Generate an array of random numbers

Hi, this is a good challenged! I think this can work. *reset the seed for the random number generator. execseed = 1 + gmillisec(jnow); Set W /1*10/ select(W); alias(W,Wp); select(W)=NO; Parameter Coef(W) p A /70/ ; loop(W$(ord(w) le floor(A*card(W)/100)), p = uniformInt(1,card(W)); while( sum(Wp$(or...
by Manassaldi
2 weeks ago
Forum: Syntax
Topic: Index change for constraints
Replies: 4
Views: 130

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
2 weeks ago
Forum: Syntax
Topic: Index change for constraints
Replies: 4
Views: 130

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 month ago
Forum: Syntax
Topic: Question about replacing two sets
Replies: 6
Views: 254

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
2 months ago
Forum: Syntax
Topic: Matrix multiplication in GAMS
Replies: 1
Views: 127

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
3 months ago
Forum: Syntax
Topic: linearization of power function
Replies: 1
Views: 303

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
4 months ago
Forum: Syntax
Topic: Syntax for sets
Replies: 2
Views: 212

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 ...