use and misuse of dynamic sets                                                                        09/24/01 10:55:40  PAGE      1
                                                                                                      GAMS Rev 121  Linux/Intel     


    2   
    3  set
    4      i/1*1000/
    5      j(i)
    6      k(i,i)
    7      l(i,i) /1*10 . 1*10/
    8      m(i) /1*10, 20*30/;
    9   
   10  * define j to be a dynamic set - the first 300 elements of i
   11  j(i)$(ord(i) < 300) = yes;
   12   
   13  * k a dynamic set also - the cartesian product of i and j
   14  k(i,j) = yes;
   15   
   16  scalar n, val;
   17   
   18  * card() operation legal for both static and dynamic sets
   19  n = card(j); display n;
   20  n = card(k); display n;
   21  n = card(l); display n;
   22   
   23  * ord() operation valid only for static sets; by using it here we are
   24  * establishing m as a static set
   25  loop(m,
   26          val = ord(m); display val;
   27  );
   28   
   29  * the following assignment requires m to be dynamic and is disallowed,
   30  * since it has already been established as a static set.
   31  m('40') = yes;
****   $199
**** 199  Assigning to set used in 'ord' or lag
****         this statement changes the content of a set
****         previously used with 'ord' or lag/lead.
   32   
   33  * the following statement doesn't work, since ord() is not defined on a
   34  * dynamic set, and we have established j as dynamic above
   35  loop(j,
   36          val = ord(j);
****                     $197
**** 197  Lag or 'ord' illegal with non constant set
****         or use of a * universe
   37          display val;
   38  );

**** 2 ERROR(S)   0 WARNING(S)


COMPILATION TIME     =        0.010 SECONDS    0.7 Mb      LNX200-121


USER: Computer Sciences Dept.                        G010628:1627AS-LNX
      University of Wisconsin-Madison                            DC2621 

**** FILE SUMMARY

INPUT      /afs/cs.wisc.edu/u/s/w/swright/public/html/635/examples/dynamic.gms
OUTPUT     /afs/cs.wisc.edu/u/s/w/swright/public/html/635/examples/dynamic.lst

**** USER ERROR(S) ENCOUNTERED