Re: [Help-glpk] how to defne an array (something like pointer to pointer in C)
> thank you all,it worked well,but i have another question:
> i have a parameter Ec: AB BC CD DE:=
> AB 0 1 1 0
> BC 1 0 1 1
> CD 1 1 0 1
> DE 0 1 1 0;
> and it means that for example nodes AB and BC are connected, and AB and
> CD are also connected. Ec has a 1 value for each two nodes that are
> connected.
> the problem is that i want to define a var x like this:
> var x {u in Vc, v in Vc} binary >=0; ""if (u,v) in Ec""
> and we have: Vc := AB BC CD DE;
> i mean i want to have var x just for those pairs of Vc that have value 1
> in Ec, i want to define something like this:
> if EC[u,v]==1 then var x {u in Vc, v in Vc} binary >=0;
> but i don't know how to write if clauses.
> i'd be really grateful if you could help me with this problem too.
var x{u un Vc, v in Vc: EC[u,v] = 1}, binary;
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Re: [Help-glpk] how to defne an array (something like pointer to pointer in C)
thank you all,it worked well,but i have another question:
i have a parameter Ec: AB BC CD DE:=
AB 0 1 1 0
BC 1 0 1 1
CD 1 1 0 1
DE 0 1 1 0;
and it means that for example nodes AB and BC are connected, and AB and CD
are also connected. Ec has a 1 value for each two nodes that are connected.
the problem is that i want to define a var x like this:
var x {u in Vc, v in Vc} binary >=0; ""if (u,v) in Ec""
and we have: Vc := AB BC CD DE;
i mean i want to have var x just for those pairs of Vc that have value 1 in
Ec, i want to define something like this:
if EC[u,v]==1 then var x {u in Vc, v in Vc} binary >=0;
but i don't know how to write if clauses.
i'd be really grateful if you could help me with this problem too.
Many thanks.
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Re: [Help-glpk] how to defne an array (something like pointer to pointer in C)
> I am new to glpk and MathProg. I am trying to model a problem in glpk
> and solve it. The problem is that I don’t know how should I define the
> following :
> We have E[i] for each i that is member of N :
> N is a set that contains A B C D E,
> So, we have E[A], E[B], E[C], E[D], E[E]
> The value for each of these members is as follows, for example:
> E[A]:= AB
> E[B] := AB BC
> E[C] := BC CD
> E[D] := CD DE
> E[E] := DE
> The problem is that I don’t know how to define E with the above
> specifications!
> I have tested the followings and it didn’t work:
> 1)
> param E:=
> A AB;
> B AB BC
> C BC CD
> D CD DE
> E DE;
> 2)
> param E :
> if i==A
> then AB
> else if i==B
> then AB BC
> else if i==C
> then BC CD
> else if i==D
> then CD DE
> else if i==E
> then DE;
> 3)
> set EA; /*set of edges connected to node A*/
> set EB; /*set of edges connected to node B*/
> set EC; /*set of edges connected to node C*/
> set ED; /*set of edges connected to node D*/
> set EE; /*set of edges connected to node E*/
> set EA := AB;
> set EB := AB BC;
> set EC := BC CD;
> set ED := CD DE;
> set EE := DE;
> and also we have:
> u can be AB BC CD DE
> and after defining the E, I have to check something like this:
> for each I in N, for each u that is in E[i] ….some condition……
> I really don’t know how should I solve this problem,how to define E,
> and it is very essential to solve this problem..
> Please do me a favor and help!
> Many thanks in advance.
You may try something like this:
set N;
set E{i in N}, dimen 2;
display E;
data;
set N := A B C D E;
set E[A] := (A,B);
set E[B] := (A,B) (B,C);
set E[C] := (B,C) (C,D);
set E[D] := (C,D) (D,E);
set E[E] := (D,E);
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Re: [Help-glpk] how to defne an array (something like pointer to pointer in C)
Hello Maryam,
you could use the following formulation
set N;
set E{n in N};
display E;
data;
set N:= A B C D E;
set E[A]:= A AB;
set E[B]:= AB BC;
set E[C]:= BC CD;
set E[D]:= CD DE;
set E[E]:= DE;
end;
If you have large data sets consider using the table statement described in
doc\tables.pdf to read the data from a SQL database or from a CSV file.
Best regards
Xypron
Best regards
Xypron
Maryam Ahmadi wrote:
>
> Dear All,
>
> I am new to glpk and MathProg. I am trying to model a problem in glpk
> and solve it. The problem is that I don’t know how should I define the
> following :
> We have E[i] for each i that is member of N :
> N is a set that contains A B C D E,
> So, we have E[A], E[B], E[C], E[D], E[E]
> The value for each of these members is as follows, for example:
> E[A]:= AB
> E[B] := AB BC
> E[C] := BC CD
> E[D] := CD DE
> E[E] := DE
> The problem is that I don’t know how to define E with the above
> specifications!
>
> I have tested the followings and it didn’t work:
> 1)
> param E:=
> A AB;
> B AB BC
> C BC CD
> D CD DE
> E DE;
>
> 2)
> param E :
> if i==A
> then AB
> else if i==B
> then AB BC
> else if i==C
> then BC CD
> else if i==D
> then CD DE
> else if i==E
> then DE;
> 3)
> set EA; /*set of edges connected to node A*/
> set EB; /*set of edges connected to node B*/
> set EC; /*set of edges connected to node C*/
> set ED; /*set of edges connected to node D*/
> set EE; /*set of edges connected to node E*/
> set EA := AB;
> set EB := AB BC;
> set EC := BC CD;
> set ED := CD DE;
> set EE := DE;
>
> and also we have:
> u can be AB BC CD DE
> and after defining the E, I have to check something like this:
> for each I in N, for each u that is in E[i] ….some condition……
>
> I really don’t know how should I solve this problem,how to define E,
> and it is very essential to solve this problem..
> Please do me a favor and help!
> Many thanks in advance.
> Regards
>
>
> ___
> Help-glpk mailing list
> Help-glpk@gnu.org
> http://lists.gnu.org/mailman/listinfo/help-glpk
>
>
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[Help-glpk] how to defne an array (something like pointer to pointer in C)
Dear All, I am new to glpk and MathProg. I am trying to model a problem in glpk and solve it. The problem is that I don’t know how should I define the following : We have E[i] for each i that is member of N : N is a set that contains A B C D E, So, we have E[A], E[B], E[C], E[D], E[E] The value for each of these members is as follows, for example: E[A]:= AB E[B] := AB BC E[C] := BC CD E[D] := CD DE E[E] := DE The problem is that I don’t know how to define E with the above specifications! I have tested the followings and it didn’t work: 1) param E:= A AB; B AB BC C BC CD D CD DE E DE; 2) param E : if i==A then AB else if i==B then AB BC else if i==C then BC CD else if i==D then CD DE else if i==E then DE; 3) set EA; /*set of edges connected to node A*/ set EB; /*set of edges connected to node B*/ set EC; /*set of edges connected to node C*/ set ED; /*set of edges connected to node D*/ set EE; /*set of edges connected to node E*/ set EA := AB; set EB := AB BC; set EC := BC CD; set ED := CD DE; set EE := DE; and also we have: u can be AB BC CD DE and after defining the E, I have to check something like this: for each I in N, for each u that is in E[i] ….some condition…… I really don’t know how should I solve this problem,how to define E, and it is very essential to solve this problem.. Please do me a favor and help! Many thanks in advance. Regards ___ Help-glpk mailing list Help-glpk@gnu.org http://lists.gnu.org/mailman/listinfo/help-glpk
