B.M. Smith. Succeed-first or fail-first: A case study in variable and value ordering. In Proceedings of PACT-1997, pages 321--330, 1997.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....m i of cars requiring option i with respect to the maximum number of cars in a sequence which could have option i while satisfying the capacity constraint on i (i.e. 100 m i q i = n p i ) 5] A high utilization percentage indicates that the demand is very close to the capacity. Hence, [19] and [17] introduced value ordering heuristics: the idea is to assign first the cars requiring options with high utilization percentages, corresponding to critical options. Such value ordering heuristics have been incorporated in Ant P solver in a very straightforward way, by increasing the ....

B. Smith, `Succeed-first or fail-first: A case study in variable and value ordering heuristics', in third Conference on the Practical Applications of Constraint Technology PACT'97, pp. 321--330, (1996).

....on all the variables. With this modelization it is difficult to solve some instances of the problem when r is greater than 6. Thus we have to improve this model, but how can we do it At present, we are not able to give a general answer to this question. There are few studies on this topic [5, 4]. In fact, it may not be easy to identify the parts of the problem that lend themselves to relevant subproblems. For instance, we would like to know if it is interesting to be able to achieve arc consistency for the constraint sum of n all different variables . That is, if it would be of interest ....

B.M. Smith. Succeed-first or fail-first: A case study in variable and value ordering. In proceedings ILOG Solver and ILOG Scheduler Second International Users' Conference, Paris, France, 1996.

.... than s is expressed by propagators corresponding to constraints of the form h 1 Delta Delta Delta h s s Delta Delta Delta h n Gammas 1 Delta Delta Delta h n s This approach to such sequence constraints in the context of finite domain constraint programming is present in [17]. It seems to be adequate with the problem sizes at hand; more powerful propagation algorithms are presented in [13] In the presence of sequence constraints, the most effective search strategy seems to be to enumerate the h, a and b variables date wise, i.e. in the order h 1 ; a 1 ; b 1 ; h 2 ; ....

Barbara Smith. Succeed-first or fail-first: A case study in variable and value ordering. In Proceedings of the 1996 ILOG Solver and ILOG Scheduler International Users' Conference, Paris, July 1996.

....example, if a car needs a sun roof it may not be possible to install one on either of the next two cars. The problem is to sequence the production such that the capacity constraints are respected. The car sequencing problem has received recent interest within the constraint programming community [5, 6]. One important issue that has arisen is precisely the most appropriate formulation to use to solve the problems [5] There are two natural possibilities. One is that the cars are regarded as variables, with their values giving their position in the sequence. The other is to regard positions in ....

....is to sequence the production such that the capacity constraints are respected. The car sequencing problem has received recent interest within the constraint programming community [5, 6] One important issue that has arisen is precisely the most appropriate formulation to use to solve the problems [5]. There are two natural possibilities. One is that the cars are regarded as variables, with their values giving their position in the sequence. The other is to regard positions in the sequence as variables, the value indicating the car to be put in that position. Smith showed that the conventional ....

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B.M. Smith. Succeed-first or fail-first: A case study in variable and value ordering. In Proceedings of PACT'97, pages 321--330, 1997.

....of constraint satisfaction sequencing problems include rostering and the car sequencing problem. In recent years specialised propagation and search techniques have been developed to deal with such problems within the constraint programming framework (Dincbas, Simonis, Van Hentenryck, 1988; Smith, 1996; Re gin Puget, 1997) These techniques all use constructive search, powerful propagation techniques and backtracking. In this paper we examine an alternative approach: local search techniques to tackle the constraint satisfaction sequencing problem. The advantages of developing local search ....

Smith, B. M. (1996). Succeed-first or fail-first: A case study in variable and value ordering. In Proceedings ILOG Solver and ILOG Scheduler Second International Users' Conference.

.... cars on a production line, and goes back in the constraint programming community to [1] having previously been defined by Parello, Kabat and Wos [5, 6] More recently, the problem has again attracted attention as it provides fertile ground for the study of formulations and search methods [7, 8]. Each car requires some subset of the set of possible customising options . We must schedule the order of cars to be put on the line. Unfortunately each option is subject to a capacity constraint. For example, if a car needs a sunroof, it may not be possible to install one on either of the next ....

....in the graph between nodes i and j. So by the definition of the translation, the edges car e i does not require option E j . 3 Solution to an Open Car Sequencing Problem R egin and Puget [7] introduce a filtering technique and describe its use on hard car sequencing problems proposed by Smith [8]. They solve four, of which two are solvable and two not. One problem remained open. To their credit, R egin and Puget list the problem in full and mention their failure, even emphasising it in their talk at CP 97. Such reporting of negative results is to be encouraged. The problem is as described ....

B.M. Smith. Succeed-first or fail-first: A case study in variable and value ordering. In Proceedings of PACT'97, pages 321--330, 1997. 1 http://www.cs.strath.ac.uk/~apes

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B.M. Smith. Succeed-first or fail-first: A case study in variable and value ordering. In Proceedings of PACT-1997, pages 321--330, 1997.

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