[gecode-users] Issue with a MiniZinc model

[Lucie Kučerová]

Hi,

I thought it would be this sort of a newbie problem... Thank you very
much for the quick response!

Lucie


Dne 13.1.2011 15:16, Mikael Zayenz Lagerkvist napsal(a):
> Hi,
> 
> Your model specifies that the values for resources could be anything (in
> Gecode, that is approximately from -2 billion to +2 billion). Any
> negative value for resources leads to a failure, but that is not
> detected until it is tried since your model uses reified constraints. It
> is very important to always think about the size of your initial domain.
> 
> The crash you see is simply when your computer has run out of memory for
> the search-tree you are generating. Try a few variants with the minimum
> value for resources being 0, -10, -100, -1000 and run it in Gist (fz -
> mode gist) to see the resulting search tree. 
> 
> Cheers,
> Mikael
> 
> 2011/1/13 Lucie Kučerová <lucie.kucerova at mensa.cz
> <mailto:lucie.kucerova at mensa.cz>>
> 
>     Hello,
> 
>     I've created a simple MiniZinc model describing a planning domain &
>     problem. The issue is that although MiniZinc itself solves it instantly,
>     when I use Gecode's fz.exe on the generated FlatZinc model, the program
>     computes for a while and then crashes.
> 
>     The MiniZinc model in question is attached below. The only problematic
>     constraint is the last one from the succesor state constraints, without
>     it all works OK. Any ideas what is causing the issue?
> 
>     Thank you in advance
>     Lucie Kucerova
> 
> 
> 
>     % Constants
>     int: t = 2;
>     int: num_preds = 5;
>     int: num_actions = 6;
>     int: num_resc = 1;
> 
>     % Variables
>     array[0..t, 0..num_preds - 1] of var bool: predicates;
>     array[0..t - 1, 0..num_actions - 1] of var bool: actions;
>     array[0..t, 0..num_resc - 1] of var int: resources;
> 
>     % Constraints
> 
>     % Init
>     constraint predicates[0, 0];
>     constraint not predicates[0, 1];
>     constraint not predicates[0, 2];
>     constraint not predicates[0, 3];
>     constraint not predicates[0, 4];
>     constraint resources[0, 0] = 0;
> 
>     % Goal
>     constraint predicates[t, 3];
>     constraint predicates[t, 4];
>     constraint resources[t, 0] = 100;
> 
>     % Preconditions
>     constraint forall (i in 0..t - 1) (actions[i, 0] -> predicates[i, 0]);
>     constraint forall (i in 0..t - 1) (actions[i, 1] -> predicates[i, 1]);
>     constraint forall (i in 0..t - 1) (actions[i, 2] -> predicates[i, 0]);
>     constraint forall (i in 0..t - 1) (actions[i, 3] -> predicates[i, 2]);
> 
>     % Succesor state
>     constraint forall (i in 1..t) (predicates[i, 0] <-> predicates[i - 1, 0]
>     /\ not actions[i - 1, 0] /\ not actions[i - 1, 2]);
>     constraint forall (i in 1..t) (predicates[i, 1] <-> actions[i - 1, 0] \/
>     (predicates[i - 1, 1] /\ not actions[i - 1, 1]));
>     constraint forall (i in 1..t) (predicates[i, 2] <-> actions[i - 1, 1] \/
>     actions[i - 1, 2] \/ (predicates[i - 1, 2] /\ not actions[i - 1, 3]));
>     constraint forall (i in 1..t) (predicates[i, 3] <-> actions[i - 1, 3] \/
>     predicates[i - 1, 3]);
>     constraint forall (i in 1..t) (predicates[i, 4] <-> actions[i - 1, 4] \/
>     predicates[i - 1, 4]);
>     constraint forall (i in 1..t) ((resources[i, 0] = resources[i - 1, 0])
>     \/ ((resources[i, 0] = resources[i - 1, 0] + 100) /\ actions[i - 1,
>     5]));
> 
>     % Incompatible predicates
>     constraint forall (i in 0..t) (bool2int(predicates[i, 0]) +
>     bool2int(predicates[i, 1]) + bool2int(predicates[i, 2]) +
>     bool2int(predicates[i, 3]) < 2);
> 
>     % Solution
>     solve satisfy;
> 
>     % Output
>     output
>      [ show(predicates[i,j]) ++ " " ++ if j == num_preds - 1 then "\n" else
>     " " endif | i in 0..t, j in 0..num_preds - 1] ++
>      ["\n"] ++
>      [ show(resources[i,j]) ++ " " ++ if j == num_resc - 1 then "\n" else "
>     " endif | i in 0..t, j in 0..num_resc - 1] ++
>      ["\n"] ++
>      [ show(actions[i,j]) ++ if j == num_actions - 1 then "\n" else " "
>     endif | i in 0..t - 1, j in 0..num_actions - 1];
> 
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> 
> 
> 
> 
> -- 
> Mikael Zayenz Lagerkvist, http://www.ict.kth.se/~zayenz/
> 
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> Verze: 10.0.1191 / Virová báze: 1435/3376 - Datum vydání: 12.1.2011
>