Re: [Help-glpk] Single index for multidimensional sets

[Mate Hegyhati]

Dear Xypron,

thank You, I was also thinking on using & and define one dimensional set
of "pairs" like that.

This tuple index symbol would be an interesting feature.

Anyway, thank You again, this solves my problem.

Best regards,

Mate

P.S.: I tried, whether this catenations can work in a "preprocessing"
fashion like this:

set S1;
set S2;
set S3 := setof {s1 in S1, s2 in S2: s1!=s2} s1&' , '&s2;

var x{s1 in S1, s2 in S2};

s.t. constraint {s3 in S3}:
  x[s3]=0;

but unfortunately it doesn't.


On 07/17/2012 05:01 PM, glpk xypron wrote:
> Hello Mate,
> 
> a index symbol is always scalar and never a tuple. But you can use
> string concatenation for merging your indices:
> 
> set S1; set S2; 
> set S3 := setof {s1 in S1, s2 in S2: s1!=s2} s1&","&s2;
> set S4 := setof {s1 in S1, s2 in S2: s1<s2}  s1&","&s2;
> 
> param p{S3}, default 3;
> 
> var x{s3 in S3};
> 
> s.t. constraint1{s3 in S3}: x[s3]>=p[s3];
> 
> s.t. constraint2{s4 in S4}: x[s4] >= 2 * p[s4];
> 
> data; set S1 := s11 s12; set S2 := s21 s22 s23; end;
> 
> Best regards
> 
> Xypron -------- Original-Nachricht --------
>> Datum: Tue, 17 Jul 2012 15:30:07 +0200 Von: Mate Hegyhati
>> <address@hidden> An: address@hidden Betreff:
>> [Help-glpk] Single index for multidimensional sets
> 
>> Dear All,
>> 
>> is it somehow possible to use a single index symbol for addressing
>> an n-tuple? In one of my problems I have a 3 dimensional set, that
>> is used as a basis for other sets, etc. I'm trying to do something
>> like this:
>> 
>> set S1; set S2; set S3 := setof {s1 in S1, s2 in S2: s1!=s2}
>> (s1,s2);
>> 
>> param p{s1 in S1, s2 in S2}, default 3;
>> 
>> var x{s3 in S3}; # this is, that should be (s1,s2) in S3
>> 
>> s.t. constraint1 {s3 in S3}: # similar here x[s3]>=p[s3];
>> 
>> s.t. constraint2{s1 in S1, s2 in S2: s1<s2}: x[s1,s2] >= 2 *
>> p[s1,s2];
>> 
>> It is not working, and according to the manual, an index should
>> match the dimension of the set. Is it somehow possible to avoid
>> writing (s1,s2) everywhere?
>> 
>> Thank You very much in advance, best regards,
>> 
>> Mate Hegyhati

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