
From:  Mate Hegyhati 
Subject:  Re: next question  find some element of a set 
Date:  Thu, 12 Dec 2019 08:29:10 +0100 
Useragent:  Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 
Hi!I'm not exactly sure, what you would like to do, but you could just say, but maybe this answers your question:
set sports; param favorite symbolic in sports; var train{sports} >=0; s.t. foobar: train[favorite] >=2; minimize work: sum{f in sports} train[f]; data; set sports := running cycling swimming; param favorite := 'running'; end;So put ' around the name for a symbolic parameter, and also don't put comma between set elements.
I hope this helped. If not, please clarify your situation. All the best, Mate
set := A, B, C; param some_element_in_set, symbolic := ?????;The closest I saw was in this old helpglpk email: https://lists.gnu.org/archive/html/helpglpk/200611/msg00059.htmlWhich says: set S; param ref{i in 1..card(S)}, symbolic, in S; # ref[i] refers to ith element of S; param a{S}; ... a[ref[i]] ... # means a[ith element of S]But I cannot get this to work. If I could get it to work, then I would do something like: param some_element_in_set := ref[1];BTW, I’m still hoping that someone will help solve how to work the sudoku_excel.mod example in the ‘examples\sql’ directory of the GLPK directory under Windows 10 64bit. I still cannot get that to work.Marc
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