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Re: Excessive copies of set elements in GMPL
From: |
Domingo Alvarez Duarte |
Subject: |
Re: Excessive copies of set elements in GMPL |
Date: |
Fri, 24 Jul 2020 08:58:12 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 |
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?
- Re: Excessive copies of set elements in GMPL, Andrew Makhorin, 2020/07/16
- Re: Excessive copies of set elements in GMPL, Domingo Alvarez Duarte, 2020/07/16
- Re: Excessive copies of set elements in GMPL, Domingo Alvarez Duarte, 2020/07/16
- Re: Excessive copies of set elements in GMPL, Andrew Makhorin, 2020/07/16
- Re: Excessive copies of set elements in GMPL, Domingo Alvarez Duarte, 2020/07/16
- Re: Excessive copies of set elements in GMPL, Andrew Makhorin, 2020/07/16
- Re: Excessive copies of set elements in GMPL, Domingo Alvarez Duarte, 2020/07/17
- Re: Excessive copies of set elements in GMPL, Michael Hennebry, 2020/07/21
- Re: Excessive copies of set elements in GMPL, Domingo Alvarez Duarte, 2020/07/21
- Re: Excessive copies of set elements in GMPL, Michael Hennebry, 2020/07/23
- Re: Excessive copies of set elements in GMPL,
Domingo Alvarez Duarte <=
- Re: Excessive copies of set elements in GMPL, Domingo Alvarez Duarte, 2020/07/24
- Re: Excessive copies of set elements in GMPL, Domingo Alvarez Duarte, 2020/07/24
- Re: Excessive copies of set elements in GMPL, Andrew Makhorin, 2020/07/24
- Re: Excessive copies of set elements in GMPL, Andrew Makhorin, 2020/07/24
- Is this code correct in the GMPL implementation ?, Domingo Alvarez Duarte, 2020/07/25
- Re: Is this code correct in the GMPL implementation ?, Andrew Makhorin, 2020/07/25
- Re: Excessive copies of set elements in GMPL, Domingo Alvarez Duarte, 2020/07/24
- Re: Excessive copies of set elements in GMPL, Michael Hennebry, 2020/07/24
- Re: Excessive copies of set elements in GMPL, Andrew Makhorin, 2020/07/25