Sannella M (1993), The SkyBlue Constraint Solver. TR-92-07-02, Dept. of Computer Science, University of Washington.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....has to find the optimal constraint graph, to update all changed variables, to handle modifications in broken paths, and to collect all the information needed to update the history of variables and to execute reactions and daemons. The constraint solver used in VB2 is based on the SkyBlue [32] local propagation algorithm, a successor of DeltaBlue [11] able to handle hierarchical constraints composed of methods having multiple outputs. The SkyBlue constraint satisfier is very efficient and domainindependent, since the algorithm consists on performing method selection on the basis of ....

Sannella M (1993), The SkyBlue Constraint Solver. TR-92-07-02, Dept. of Computer Science, University of Washington.

....constraints at the beginning of its life time, and removes the constraints when its life time ends. We distinguish between one way and multi way constraints. One way constraints know their solution strategy, whereas multi way constraints are solved by an external constraint solver, e.g. SkyBlue [25]. Constraint networks are anchored in behavior graphs and connected to the flow of time and events by behavior nodes. 4.7.1 Mappings In general, one way constraint nodes for graphics objects apply time dependent functions to parameters of graphics objects. MAM VRS encapsulates these functions in ....

M. Sannella, The SkyBlue Constraint Solver, TR-92-07-02, Dept. of Computer Science, University of Washington, 1992.

....preference settings, via appropriate back channel signals as need arises. As an alternative to more conventional approaches, the requirements placed by the G TS PAC model on subjects suggest the use of a constraint system (see, for example, DeltaBlue [Freeman Benson and Maloney, 1989] and SkyBlue [Sannella, 1992]) for the implementation of subjects, and of objects in particular. Dynamic relationships among subjects can be implemented in very direct terms using constraint based mechanisms. However, since the G TS PAC model presents no special considerations for the design or implementation of a constraint ....

Sannella, M. (1992). The SkyBlue Constraint Solver. Technical Report 92-07-02, University of Washington, Dept. of Computer Science and Engineering.

....algorithm has to find the optimal constraint graph, to update all changed variables, to handle modifications in broken paths, and to collect all the information needed to update the history of variables and to execute reactions and daemons. The constraint solver used in VB2 is based on the SkyBlue [32] local propagation algorithm, a successor of DeltaBlue [11] able to handle hierarchical constraints composed of methods having multiple outputs. The SkyBlue constraint satisfier is very efficient and domainindependent, since the algorithm consists on performing method selection on the basis of ....

Sannella M (1993), The SkyBlue Constraint Solver. TR-92-07-02, Dept. of Computer Science, University of Washington.

....as possible. For example the constraints v 2 = 1 and v 2 = 2 are in conflict. However, if v 2 = 1 and v 2 = 2 are, respectively labeled with strength strong and weak. The constraint system is solved by satisfying only the constraint v 2 = 1. The existing solvers (Blue, DeltaBlue, SkyBlue [6, 7, 8]) for over constrained systems, are based on local criteria: valuation comparison. According to these local criteria, many valuations might not be possible to compare (i.e two different valuations satisfying two disjoint constraint sets are not comparable) and regarding the semantics of the ....

....solver is the extension of the one described in [10] It handles different classes of soft constraints labeled with a strength where each class may contain weighted constraints. The global criterion used by this solver is based on the sum of weights of satisfied constraints. Like the solvers in [6, 7, 8, 9, 10], this solver plans a solution graph, and applies local propagation to them. 2 THEORY OF FUNCTIONAL CONSTRAINT HIERARCHIES Each functional constraint has a set of methods that can be invoked to satisfy the constraint. For example, the constraint v 1 = v 2 Gamma v 3 has three methods: v 1 v 2 ....

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M. Sannella. The skyblue constraint solver. Tech. rep., University of Washington, February 1992.

....an incremental version of Blue [22, 58, 76] Both of them embody a problem that they cannot solve hierarchies involving cycles. Suzuki et al. modified DeltaBlue in three ways to speed up its planning phase [80] SkyBlue is an incremental algorithm for solving hierarchies of multi way constraints [70, 71, 72, 73, 74, 75]. It addresses simultaneous constraints using pluggable cycle solvers, and handles constraints with multi output methods. QuickPlan is an algorithm for incrementally resolving hierarchies of multi way constraints [86] It can solve constraint hierarchies if they have at least one acyclic solution ....

Sannella, M., "The SkyBlue Constraint Solver," Tech. Rep. 92-07-02, Dept. of Computer Science and Engineering, University of Washington, Feb. 1993.

.... constraints represented as linear equations or multi way constraints, one that treats least squares better linear equation constraints, and one that generates graph layouts based on the spring model [3] 4 Comparison with SkyBlue SkyBlue is a successor of the DeltaBlue algorithm [7]. Like DeltaBlue, SkyBlue solves hierarchies of multiway constraints using locally graph better, a variation of locally predicate better. Moreover, it supports constraints with multi output methods and cycles of constraints. A method of a constraint is a procedure used to satisfy the constraint, ....

Sannella, M., "The SkyBlue Constraint Solver," Technical Report 92-07-02, Department of Computer Science and Engineering, University of Washington, Feb. 1993.

....Proteus to manage style information for program source code in the Ensemble software development environment [1] and in the process have exposed a serious limitation to the scalability of existing constraintmanagement systems: memory usage. The central problem is that existing constraint systems [4, 13] treat the attributes of document elements and the constraints between them as first class objects. 2 Anonymous Program syntax trees are quite large. In Ensemble, the abstract syntax tree for a 21 line Java fragment contains 91 lexemes (the text fragments that must be laid out and displayed) and ....

....usage. The space efficiency problems seen with the Shilpe runtime system are not unique to it or to Hudson s algorithm. They would also be observed with any other constraint system that treats cached attribute values and constraints as first class objects, such as the SkyBlue constraint solver [13]. 3. The Protean Runtime System The Protean runtime system preserves the approach to incremental attribute evaluation that was used in Shilpe, but uses a more sophisticated algorithm to handle dependencies along with very compact runtime data structures to improve the memory usage and runtime ....

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Michael Sannella. The SkyBlue constraint solver. Technical Report 92-07-02, University of Washington Department of Computer Science, 1992. Available at http://www.cs.washington.edu/research/constraints. 14 Anonymous

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