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 > > -- View this message in context: http://www.nabble.com/how-to-defne-an-array-%28something-like-pointer-to-pointer-in-C%29-tp23479009p23489985.html Sent from the Gnu - GLPK - Help mailing list archive at Nabble.com. _______________________________________________ Help-glpk mailing list Help-glpk@gnu.org http://lists.gnu.org/mailman/listinfo/help-glpk