Re: Excessive copies of set elements in GMPL

[Domingo Alvarez Duarte]

Here is the output of the script from the previous message:

Memory usage:

ubuntu glpsol package : 4,544 KB

glpk with my changes: 3,268 KB

====

/usr/bin/time glpsol -m test-nested-sets.mod
GLPSOL: GLPK LP/MIP Solver, v4.65
Parameter(s) specified in the command line:
 -m test-nested-sets.mod
Reading model section from test-nested-sets.mod...
test-nested-sets.mod:12: warning: unexpected end of file; missing end 
statement inserted
12 lines were read
A count: 10
B count: 20
C count: 30
D count: 10
Display statement at line 12
D:
   (1,2,4)
   (2,3,5)
   (3,4,6)
   (4,5,7)
   (5,6,8)
   (6,7,9)
   (7,8,10)
   (8,9,11)
   (9,10,12)
   (10,11,13)
Model has been successfully generated
GLPK Simplex Optimizer, v4.65
0 rows, 0 columns, 0 non-zeros
~     0: obj =   0.000000000e+00  infeas =  0.000e+00
OPTIMAL SOLUTION FOUND
Time used:   0.0 secs
Memory used: 1.5 Mb (1543589 bytes)
0.00user 0.00system 0:00.01elapsed 80%CPU (0avgtext+0avgdata 
4544maxresident)k
0inputs+0outputs (0major+516minor)pagefaults 0swaps

/usr/bin/time myglpsol -m test-nested-sets.mod
GLPSOL: GLPK LP/MIP Solver, v4.65
Parameter(s) specified in the command line:
 -m test-nested-sets.mod
Reading model section from test-nested-sets.mod...
test-nested-sets.mod:12: warning: unexpected end of file; missing end 
statement inserted
12 lines were read
A count: 10
B count: 20
C count: 30
D count: 10
Display statement at line 12
D:
   (1,2,4)
   (2,3,5)
   (3,4,6)
   (4,5,7)
   (5,6,8)
   (6,7,9)
   (7,8,10)
   (8,9,11)
   (9,10,12)
   (10,11,13)
Model has been successfully generated
GLPK Simplex Optimizer, v4.65
0 rows, 0 columns, 0 non-zeros
~     0: obj =   0.000000000e+00  infeas =  0.000e+00
OPTIMAL SOLUTION FOUND
Time used:   0.0 secs
Memory used: 0.5 Mb (507469 bytes)
0.00user 0.00system 0:00.00elapsed 100%CPU (0avgtext+0avgdata 
3268maxresident)k
0inputs+0outputs (0major+214minor)pagefaults 0swaps

====

On 24/7/20 8:58, Domingo Alvarez Duarte wrote:
> Hello Michael !
>
> What kind of problem do you expect ? Other than memory size 
> requirements ?
>
> Do you mean something like this:
>
> ====
>
> set A := {1..10};
> set B := {1..20};
> set C := {1..30};
>
> set D := { (a,b,c) in A cross B cross C : b=a+1 and c=b+2 };
>
> printf "A count: %d\n", card(A);
> printf "B count: %d\n", card(B);
> printf "C count: %d\n", card(C);
> printf "D count: %d\n", card(D);
>
> display D;
>
> ====
>
> A count: 10
> B count: 20
> C count: 30
> D count: 10
> Display statement at line 12
> D:
>    (1,2,4)
>    (2,3,5)
>    (3,4,6)
>    (4,5,7)
>    (5,6,8)
>    (6,7,9)
>    (7,8,10)
>    (8,9,11)
>    (9,10,12)
>    (10,11,13)
>
> ====
>
> Cheers !
>
> On 23/7/20 18:40, Michael Hennebry wrote:
> > On Tue, 21 Jul 2020, Domingo Alvarez Duarte wrote:
> >
> > > Do you have any example doing what you are talking about ?
> > >
> > > In theory it should work.
> > >
> > > Right now it process all models in the "examples" folder and the 
> > > output is identical to the original GLPK/GMPL except that uses less 
> > > memory and is slightly faster.
> >
> > Things like the GMPL equivalent of { (a,b,c) in A x B x C : b=a+1, 
> > c=b+2 }
> > My understanding is that the current GMPL processor will form A x B x C
> > before applying the filtering.
> > If A, B and C have 100 items each, the inefficiency can probably be 
> > lived with.
> > If they have 1,000 items each, it will be grindly slow, assuming it 
> > finishes.
> > If they have 10,000 items each,
> > the set will be to big for the handler to store.
> >
> > Of course, done right, a set of 10,000 3-tuples should not be a problem.
> >
> > > On 21/7/20 15:24, Michael Hennebry wrote:
> > > > Are these changes supposed to deal with things like nested set 
> > > > iterations?