% Note: glossary entries for terms that are acronyms should be prefixed 'gls-' % so the non-prefixed reference is used to refer to the acronym \newglossaryentry{aggregation}{ name={constraint aggregation}, description={A technique that combines many smaller \glspl{constraint} into a one or, by exception, a few larger \glspl{constraint}.}, } \newglossaryentry{gls-ampl}{ name={AMPL:\ A Mathematical Programming Language}, description={AMPL is a \gls{cml} originally designed to serve as a common input language for mathematical \glspl{solver} (e.g., \gls{lp} and \gls{mip}). It has later been extended for other types of \glspl{solver}. See \cref{sub:back-ampl}.}, } \newglossaryentry{gls-api}{ name={Application Programming Interface (API)}, description={ A particular set of rules and specifications that a software program can follow to access and make use of the services and resources provided by another particular software program that implements that API. } } \newglossaryentry{assignment}{ name={assignment}, description={ A mapping from \glspl{prb-par} or \glspl{variable} to values. An assignment is referred to as \gls{partial} when it maps only a subset of the \glspl{prb-par} and \glspl{variable} of a \gls{model}. A \gls{parameter-assignment} is a \gls{partial} \gls{assignment} that maps only the \glspl{prb-par}, a \gls{variable-assignment} maps only the \glspl{variable}. A complete \gls{parameter-assignment} maps all \glspl{prb-par} of a \gls{model}, a complete \gls{variable-assignment} maps all \glspl{variable} of a \gls{model}. } } \newglossaryentry{gls-ast}{ name={Abstract Syntax Tree}, description={A tree structure representing the syntactic structure of a piece of computer language. These structures are often used in a \gls{compiler} or \gls{interpreter}.}, } \newglossaryentry{annotation}{ name={annotation}, description={Extra information added to \gls{minizinc} items or expressions. \gls{minizinc} can be \gls{annotated} to provide information or hints to the targeted \gls{solver} or the \gls{rewriting} process.}, } \newglossaryentry{annotated}{ name={annotated}, description={See \gls{annotation}.}, } \newglossaryentry{array}{ name={array}, description={A data structure that holds a collection of elements, each identified by an index. Provided the index of an element, the array can retrieve the element.}, } \newglossaryentry{avar}{ name={auxiliary variable}, description={ A \gls{variable} not explicitly defined in a \gls{model}, but rather introduced in the \gls{rewriting} of an \gls{instance}. Auxiliary \glspl{variable} are generally introduced to redefine an existing \gls{variable} using \glspl{variable} of a different type, to represent a sub-expression, or to connect \glspl{constraint} in a \gls{decomp}. } } \newglossaryentry{backtrack}{ name={backtrack}, description={A \gls{solver} is said to backtrack when it revisits a search decision (e.g., a value assumed during search). Notably the action of backtracking generally involves invalidating all effects of the revisited and subsequent search decisions.}, } \newglossaryentry{binding}{ name={binding}, description={A \gls{variable} is said to have a binding \gls{domain} when it is tighter than \gls{domain} that can be computed from its defining expression. A binding \gls{domain} is a \gls{constraint} of the overall \gls{model}.}, } \newglossaryentry{bnb}{ name={branch and bound}, description={A search method to find a \gls{opt-sol}. After an initial \gls{sol} is found, the search continuously looks for \glspl{sol} for which the \gls{objective} will return a better value than the incumbent \gls{sol}. If it is such a \gls{sol} cannot exist, then the final incumbent \gls{sol} is a \gls{opt-sol}.}, } \newglossaryentry{byte-code}{ name={byte-code}, description={A set of instructions designed to be efficiently executed by an \gls{interpreter}. Distinctive from other computer languages a byte code has a very compact representation, e.g., using only numbers, and can not be directly read by humans.}, } \newglossaryentry{booleanization}{ name={Booleanization}, description={The process of \gls{rewriting} a \gls{model} to a \gls{sat} or \gls{maxsat} problem.}, } \newglossaryentry{bounds}{ name={bounds}, description={The minimal and maximum value in the \domain{} of a \variable{}, i.e., the boundaries of the \domain{}.}, } \newglossaryentry{boundsr-con}{ name={bounds($\mathbb{R}$) consistent}, description={A \gls{propagator} is bounds($\mathbb{R}$) consistent when it tightens the \gls{bounds} such that they could satisfy the \gls{constraint} if it where using rational arithmetic.}, } \newglossaryentry{boundsz-con}{ name={bounds($\mathbb{Z}$) consistent}, description={A \gls{propagator} is bounds($\mathbb{Z}$) consistent when it tightens the \gls{bounds} such that they can satisfy the \gls{constraint}.}, } \newglossaryentry{gls-cbc}{ name={COIN-OR Branch-and-Cut}, description={A well-known open source \gls{mip} \gls{solver} \autocite{forrest-2020-cbc}.}, } \newglossaryentry{gls-cbls}{ name={constraint-based local search}, description={A form of local search using \gls{constraint} violations as its \gls{objective}. The search method estimate the amount a \gls{constraint} is \gls{violated} in terms of a numeric value, the objective of the search is to minimize this value. Generally \constraints{} can also offer ``search steps'' that can be taken that do not introduce new violations.}, } \newglossaryentry{chain-compression}{ name={chain compression}, description={A technique used to simplify \glspl{implication-chain}. See \cref{subsec:half-compress}.}, } \newglossaryentry{chuffed}{ name={Chuffed}, description={A well-known open source \gls{lcg} \gls{solver} \autocite{chuffed-2021-chuffed,chu-2011-chuffed}.}, } \newglossaryentry{comprehension}{ name={comprehension}, description={A syntactic construct available in \minizinc{} to construct sets and \glspl{array}. It constructs the elements based on an expression initialized by a \gls{generator}.}, } \newglossaryentry{conditional}{ name={conditional}, description={A type of expression that makes a choice between two or more expressions. In \minizinc{} these expressions take the form \mzninline{if @\(B\)@ then @\(X\)@ else @\(Y\)@endif}.}, } \newglossaryentry{gls-cnf}{ name={conjunctive normal form}, description={The formulation of a Boolean formula as a conjunction of disjunctions of Boolean literals. This is a standardized format for \gls{gls-sat} problems.}, } \newglossaryentry{constraint}{ name={constraint}, description={A formalized rule of a problem. Constraints are generally expressed in terms of Boolean logic.}, } \newglossaryentry{cml}{ name={constraint modelling language}, description={ A computer language used to define \glspl{model}. Constraint modelling languages allow modellers to define \glspl{model} in terms of \glspl{prb-par}, \gls{variable} and \glspl{constraint}. Together with a complete \gls{parameter-assignment} a \gls{model} forms an \gls{instance}. Through the process of \gls{rewriting} the \gls{instance} is transformed into a \gls{slv-mod}, for which a \gls{solver} can find \glspl{sol}. } } \newglossaryentry{cplex}{ name={CPLEX}, description={A well-known proprietary \gls{mip} \gls{solver} developed by IBM \autocite{ibm-2020-cplex}.}, } \newglossaryentry{gls-chr}{ name={constraint handling rules}, description={A non-deterministic declarative rule based programming language to maintain or improve a constraint store. Constraint handling rules are often used as an extension of \gls{clp}. See \cref{sub:back-chr}.}, } \newglossaryentry{gls-clp}{ name={constraint logic programming}, description={An extension of logic programming to include the concepts of \gls{cp}. A constraint logic program manipulates a \gls{constraint} store to find relevant variants where all \glspl{constraint} contained in the store are \gls{satisfied}. See \cref{subsec:back-clp}.}, } \newglossaryentry{gls-cp}{ name={constraint programming}, description={ A general technique to find \glspl{sol} to \glspl{instance} of \glspl{model}. A constraint programming solver interleaves \gls{propagation} with making \glspl{search-decision} to reduce the \gls{search-space}. See \cref{subsec:back-cp}. } } \newglossaryentry{gls-cse}{ name={common sub-expression elimination}, description={A technique stemming from programming language to avoid duplicate computation. In \glspl{cml} this technique is used to avoid the creation of duplicate \glspl{variable} and \glspl{constraint}. See \cref{subsec:back-cse}.}, } \newglossaryentry{confluence}{ name={confluence}, description={A property of a \gls{trs}. The system is said to be confluent if it always arrives at the same \gls{normal-form}.}, } \newglossaryentry{cvar}{ name={control variable}, description={ A special form of an \gls{avar} where the \gls{variable} represent the result of a \gls{reif}. } } \newglossaryentry{comet}{ name={COMET}, description={A \cml{} with advanced \gls{meta-optimization} functionality \autocite{michel-2005-comet}.} } \newglossaryentry{compiler}{ name={compiler}, description={ A computer program that transforms a program in a computer language, referred to as the ``source'', into a different language (or instruction set), the ``target''. The goal of this transformation is generally to create an executable version of the program. } } \newglossaryentry{compiling}{ name={compiling}, description={see \gls{compiler}.}, } \newglossaryentry{dec-prb}{ name={decision problem}, description={ A problem which can be defined as making a set of decisions under a certain set of rules. Decisions problems can be formalized as \glspl{model}. } } \newglossaryentry{decomp}{ name={decomposition}, description={ A formulation of a \gls{constraint} in terms of other \glspl{constraint} in order to reach \gls{native} \glspl{constraint}. Note that the new \glspl{constraint} can represent the same decisions using different \glspl{variable}, possibly of different types. } } \newglossaryentry{del-rew}{ name={delayed rewriting}, description={A technique using during \gls{rewriting}. It delays the \gls{rewriting} of \glspl{constraint} whose \gls{decomp} can change based on information that can become available later during the process.}, } \newglossaryentry{domain}{ name={domain}, description={A set of value that a \gls{variable} can take without violating any \glspl{constraint} in the problem.}, } \newglossaryentry{domain-con}{ name={domain consistent}, description={A \gls{propagator} is domain consistent if it is able to remove all values from \domains{} that do not occur in a \gls{sol}.}, } \newglossaryentry{essence}{ name={Essence}, description={A \gls{cml} known for its high-level \gls{variable} types. The rewriting process of Essence first transforms an Essence model into \gls{ess-prime}. A \instance{} formed with an \gls{ess-prime} model is then rewritten into a \gls{slv-mod}. See \cref{sub:back-essence}.}, } \newglossaryentry{eqsat}{ name={equisatisfiable}, description={Two \glspl{model} are equisatisfiable when a bijective function can be defined to map the \glspl{sol} of one \gls{model} onto the \glspl{sol} of the other.}, } \newglossaryentry{fixed}{ name={fixed}, description={A \gls{variable} is said to be fixed when there is only a single possible value that it can take.}, } \newglossaryentry{fixpoint}{ name={fix-point}, description={A set of algorithms is set to be at fix-point when none of the algorithms can further change the overall state.}, } \newglossaryentry{flatzinc}{ name={Flat\-Zinc}, description={A subset of \gls{minizinc} chosen to represent \glspl{slv-mod}. It is the standard format in which \gls{minizinc} communicates with its \glspl{solver}.}, } \newglossaryentry{gecode}{ name={Gecode}, description={A well-known open source \gls{cp} \gls{solver} \autocite{schulte-2019-gecode}.}, } \newglossaryentry{generator}{ name={generator}, description={An expression in \gls{minizinc} that evaluates to a sequence of elements. These elements are then generally used to instantiate an identifier in a \gls{comprehension} expression.}, } \newglossaryentry{global}{ name={global constraint}, description={ A common \gls{constraint} pattern. These patterns can generally extend to any number of \glspl{variable}. For example, the well-known global constraint \( AllDifferent(\ldots) \) requires all its arguments to take a different value. Global constraints are usually not \gls{native} to a \gls{solver}. Instead, the \gls{rewriting} process can enforce the global constraint using a \gls{decomp}. } } \newglossaryentry{gurobi}{ name={Gurobi}, description={A well-known proprietary \gls{mip} \gls{solver} \autocite{gurobi-2021-gurobi}.}, } \newglossaryentry{half-reif}{ name={half-reification}, description={A half-reification is a variation of a \gls{reif} where for a \gls{constraint} \(c\) it enforces that a \gls{cvar} \texttt{b} represents the logical implication of the \gls{constraint}: \(\texttt{b} \rightarrow{} c\).}, } \newglossaryentry{half-reified}{ name={half-reified}, description={See \gls{half-reif}.}, } \newglossaryentry{incremental-rewriting}{ name={incremental rewriting}, description={The \gls{rewriting} of an \gls{instance} that is continuously changed.}, } \newglossaryentry{implication-chain}{ name={implication chain}, description={Multiple implication \glspl{constraint} linked together through a \glspl{variable} on opposite sides of the implication, such as \mzninline{A -> B} and \mzninline{B -> C}. When a linking \gls{variable} is not used, the \glspl{constraint} can be simplified through the use of \gls{chain-compression}.}, } \newglossaryentry{int-sol}{ name={intermediate solution}, description={A \gls{sol} in an \gls{opt-prb} that is not (yet) proven to be the \gls{opt-sol}.}, } \newglossaryentry{instance}{ name={instance}, description={A \gls{model} with a complete \gls{parameter-assignment}.}, } \newglossaryentry{interpreter}{ name={interpreter}, description={ A computer program that directly executes instructions one at a time. } } \newglossaryentry{kleene-sem}{ name={Kleene semantics}, description={ A semantic model for treating undefined behaviour in \glspl{cml}. Under Kleene semantics an occurrence of undefined behaviour will only cause its surrounding expression to be undefined when its value is required to compute its result. } } \newglossaryentry{linearization}{ name={linearization}, description={The process of \gls{rewriting} a \gls{model} to a mixed integer program.}, } \newglossaryentry{let}{ name={let expression}, description={A scoping mechanism for expressions in \gls{minizinc}. A let expression allows the modeller to introduce \glspl{variable}, and constrain them, to be used only in the subsequent expression.}, } \newglossaryentry{gls-lcg}{ name={lazy clause generation}, description={Types of \gls{solver} that extend \gls{cp} solving with \gls{sat} capabilities. Lazy clause generation \glspl{solver} lazily translate a \gls{cp} model for a \gls{sat} backend. As such, they maintain the pruning ability of a \gls{cp} solver while gaining the ability of \gls{sat} solvers to explain any failures in the search.}, } \newglossaryentry{gls-lns}{ name={large neighbourhood search}, description={ A \gls{meta-optimization} strategy that repeatedly reduces the \gls{search-space} by applying different \glspl{neighbourhood} often based on a previous \gls{sol}. Large neighbourhood search is a well-known method to quickly improve a \gls{sol}. Large neighbourhood search is not guaranteed to find the \gls{opt-sol} and if it does, then it will be unable to prove that it did. } } \newglossaryentry{meta-optimization}{ name={meta-optimization}, description={ Methods used to improve on the general techniques used by \glspl{solver} to look for \glspl{sol}, such as \gls{bnb}. Meta-optimization can be used for a myriad of reasons, such as to quickly improving on an existing \gls{sol}, to find a set of diverse \glspl{sol}, or to use of complex or multiple \glspl{objective}. Although meta-optimization methods can be implemented by adjusting the search method in a \gls{solver}, they are often emulated through the adjustment of \glspl{slv-mod} based on the results from the \gls{solver}. } } \newglossaryentry{microzinc}{ name={Micro\-Zinc}, description={A subset of \gls{minizinc} used to describe transformations performed during \gls{rewriting}. Notably, well-defined \microzinc{} cannot contain partial expressions or conditions that contain \glspl{variable}.}, } \newglossaryentry{minisearch}{ name={Mini\-Search}, description={ \textcite{rendl-2015-minisearch} introduced MiniSearch as a way to describe \gls{meta-optimization} methods from within a \gls{minizinc} model. The specified \gls{meta-optimization} method would be performed either by repeatedly calling a \gls{solver} with an updated \gls{slv-mod} or using a \gls{solver} extended with a MiniSearch interface. } } \newglossaryentry{model}{ name={constraint model}, description={ A formalization of a \gls{dec-prb} or an \gls{opt-prb}. It is defined in terms of formalized decision, \glspl{variable} of different kinds (e.g., Boolean, integers, or even sets), and \glspl{constraint}, Boolean logic formulas which are forced to hold in any \gls{sol}, and, in case of an \gls{opt-prb}, an \gls{objective}. Any external data required to formulate the \glspl{constraint} is said to be the \glspl{prb-par}. The combination of a constraint model and \gls{assignment}s for its \glspl{prb-par} is said to be an \gls{instance} of the constraint model. } } \newglossaryentry{minizinc}{ name={Mini\-Zinc}, description={ The primary \gls{cml} studied in this thesis. MiniZinc is the successor to \gls{zinc} introduced in 2007 \autocite{nethercote-2007-minizinc}. An open-source implementation of the language is available \autocite{minizinc-2021-minizinc}. } } \newglossaryentry{normal-form}{ name={normal form}, description={A \gls{trs} has reached its normal form when none of the rewriting rules can be applied.}, } \newglossaryentry{gls-maxsat}{ name={Maximum Satisfiability}, description={An extension of the \gls{gls-sat} problem class into an \gls{opt-prb}. A \gls{gls-sat} problem in \gls{gls-cnf} is extended with weights for each clause. An \gls{opt-sol} of a problem \instance{} maximizes the weights of the \gls{satisfied} clauses.}, } \newglossaryentry{gls-mip}{ name={mixed integer programming}, description={ A solving technique tries to find the \gls{opt-sol} for a \cmodel{} containing a mixture of Integer and floating point \glspl{variable} subject to \glspl{constraint} in the form of linear (in-)equations. Mixed integer programming is extensively studied and there are many successful \glspl{solver} dedicated to solving mixed integer programs. See \cref{subsec:back-mip}. } } \newglossaryentry{native}{ name={native}, description={\glspl{constraint} and \gls{variable} types are said to be native to a \gls{solver} when they can be directly used as input for the \gls{solver}.}, } \newglossaryentry{nanozinc}{ name={Nano\-Zinc}, description={A language to represent the current state of an \gls{instance} during \gls{rewriting}.}, } \newglossaryentry{neighbourhood}{ name={neighbourhood}, description={A (small) subset of the \gls{search-space}.}, } \newglossaryentry{objective}{ name={objective function}, description={A function defined over the \glspl{variable} of a \gls{model} to assign a numeric value to the quality of the \gls{sol}.}, } \newglossaryentry{obj-cp}{ name={Objective-CP}, description={A library for the Objective-C programming language to provide constraint modelling functionality\autocite{hentenryck-2013-objcp}.}, } \newglossaryentry{openwbo}{ name={OpenWBO}, description={A well-known \gls{maxsat} \gls{solver} \autocite{martins-2014-openwbo}.}, } \newglossaryentry{operator}{ name={operator}, description={A syntactical symbol used as a shorthand for a function. Prefix operators, such as \mzninline{not}, appear before another expression and are a shorthand for unary functions. Infix operators, such as \mzninline{+}, \mzninline{*}, and \mzninline{div}, appear in between two expressions and are a shorthand for binary functions.}, } \newglossaryentry{gls-opl}{ name={OPL:\ The optimization modelling language}, description={A \gls{cml} aimed at combining the powers of mathematical programming and \gls{cp}. The OPL is excels at the modelling of scheduling problems. See \cref{sub:back-opl}.}, } \newglossaryentry{opt-prb}{ name={optimization problem}, description={ A decision problem with an additional \gls{objective}. It can, likewise, be formalized as a \gls{model}. If the problem has multiple \glspl{sol}, then this function can be used to assess the quality on the \gls{sol}. For such a problem, an \gls{opt-sol} is a \gls{sol} with the highest quality. } } \newglossaryentry{optional}{ name={optional}, description={When it is not certain if a value, either \gls{variable} or \gls{parameter}, will exist in a \gls{minizinc} \instance{}, its type is marked as optional (\mzninline{opt}). If the value does not occur it is said to be absent.}, } \newglossaryentry{opt-sol}{ name={optimal solution}, description={A \gls{sol} in an \gls{opt-prb} for which it has been proven that other \gls{sol} of higher quality do not exist.}, } \newglossaryentry{restart}{ name={restart}, description={ A \gls{solver} is said to restart when it abandons all \glspl{search-decision}. This can be useful when extra information has come to light in the search for a \gls{sol}. } } \newglossaryentry{rbmo}{ name={restart based meta-optimization}, description={ A technique to apply \gls{meta-optimization} methods within the \gls{solver}. The \gls{solver} is extended with \gls{native} \glspl{constraint} that set \glspl{variable} to a \gls{fixed} value on every \gls{restart}. See \cref{sec:inc-modelling,sec:inc-solver-extension}. } } \newglossaryentry{gls-sat}{ name={Boolean satisfiability}, description={ A problem class that tries to find a valid \gls{assignment} for a set of Boolean \glspl{variable} subject to a logical formula. Boolean satisfiability is extensively studied and there are many \glspl{solver} dedicated to solving this problem class. See \cref{subsec:back-sat}. } } \newglossaryentry{search-comb}{ name={search combinators}, description={A language extension proposed for \cmls{} that allows the modeller to describe search conducted by the \solver{} \autocite{schrijvers-2013-combinators}.} } \newglossaryentry{search-decision}{ name={search decision}, description={ \Glspl{solver} generally make search decisions when they can not directly infer a \gls{sol}. The \gls{solver} then assumes a value for a \gls{variable} or adds a \gls{constraint}. The decision can be to be revised later. } } \newglossaryentry{search-heuristic}{ name={search heuristic}, description={ A specification of how to make \glspl{search-decision} in an effort to find \glspl{sol} in a \gls{solver}. } } \newglossaryentry{search-space}{ name={search space}, description={ The set of possible \glspl{search-decision} in the current state of the \instance{}. } } \newglossaryentry{sol}{ name={solution}, description={A complete \gls{variable-assignment} for an \gls{instance} such that all \glspl{constraint} are satisfied.}, } \newglossaryentry{solver}{ name={solver}, description={ A computer program that is designed to solve certain types of \gls{dec-prb} and/or \gls{opt-prb}. Given a \gls{slv-mod}, in a specified format, a solver will (eventually) produce a \gls{sol} for it. When solving a \gls{opt-prb}, solvers often produce intermediate \glspl{sol} before producing the \gls{opt-sol}. } } \newglossaryentry{strict-sem}{ name={strict semantics}, description={ A semantic model for treating undefined behaviour in \glspl{cml}. Under strict semantics any occurrence of undefined behaviour will cause the result of the \gls{instance} to be undefined. } } \newglossaryentry{parameter}{ name={parameter}, description={ Parameter variables, shortened to parameters, are variables in the sense of programming languages, and are not to be confused with \glspl{variable}. In \minizinc{}, a parameter variable represents a value that will be known during \gls{rewriting}. Examples of such values are \glspl{prb-par}, the result of introspection (such as \mzninline{dom(x)}, returning the current domain of a \gls{variable} \mzninline{x}), or the result of calculations over other parameter variables. } } \newglossaryentry{parameter-assignment}{ name={parameter assignment}, description={see \gls{assignment}}, } \newglossaryentry{partial}{ name={partial}, description={A function is said to be partial when it does not have a defined result for every possible input. Similarly, an \gls{assignment} is said to be partial when it maps only a subset of the \glspl{prb-par} and \glspl{variable} in a \gls{model}.}, } \newglossaryentry{prb-par}{ name={problem parameter}, description={ Problem parameters are part of the external input for a \gls{model}. They can be used as immutable data used to define \glspl{constraint} or provide structural information about an \gls{instance}. For example, a problem parameter can influence the number of \glspl{constraint} in an \gls{instance}. } } \newglossaryentry{propagation}{ name={constraint propagation}, description={The removal of values from \glspl{domain} of \glspl{variable} that violate a \gls{constraint}. See \cref{subsec:back-cp}.}, } \newglossaryentry{propagator}{ name={propagator}, description={An algorithm that perform \gls{propagation} for a \gls{constraint}.}, } \newglossaryentry{reif}{ name={reification}, description={A reification is a special form of a \gls{constraint} where, instead of the \gls{constraint} \(c\) being enforced in the \glspl{sol}, it enforces that a \gls{cvar} \texttt{b} represents whether the \gls{constraint} holds or not: \(\texttt{b} \leftrightarrow{} c\).}, } \newglossaryentry{reified}{ name={reified}, description={See \gls{reif}.}, } \newglossaryentry{rel-sem}{ name={relational semantics}, description={ A semantic model for treating undefined behaviour in \glspl{cml}. Under relational semantics an occurrence of undefined behaviour will cause its closest surrounding Boolean expression to become \false{}. } } \newglossaryentry{rewriting}{ name={rewriting}, description={ The process of transforming a \gls{model} \gls{instance} into an \gls{eqsat} \gls{slv-mod} is referred to as rewriting. This happens primarily through the application of \glspl{decomp}. } } \newglossaryentry{satisfied}{ name={satisfied}, description={ A \gls{constraint} is said to be satisfied when its logical expression is proven to hold. Furthermore, a \gls{dec-prb} is said to be satisfied when all its \glspl{constraint} are satisfied. } } \newglossaryentry{scip}{ name={SCIP}, description={A well-known open source \gls{mip} \gls{solver}.}, } \newglossaryentry{slv-mod}{ name={solver model}, description={ A \gls{instance} of a \gls{model} where all \glspl{constraint} and \gls{variable} types are \gls{native} for the targeted \gls{solver}. \Glspl{instance} of \glspl{model} containing non-native \glspl{constraint} and/or \gls{variable} types can be transformed into solver models through the process of \gls{rewriting}. } } \newglossaryentry{sicstus}{ name={SICStus Prolog}, description={A well-known implementation of the Prolog \gls{clp} language and constraint modelling environment \autocite{carlsson-1997-sicstus}.}, } \newglossaryentry{term}{ name={term}, description={An expression in a \gls{trs}. A term can have nested sub-expressions.}, } \newglossaryentry{termination}{ name={termination}, description={A property of a \gls{trs}. A system is terminating if it is guaranteed to eventually arrive at a \gls{normal-form}.}, } \newglossaryentry{trail}{ name={trail}, description={A chronological account of changes to data structures with as goal to possibly reverse these changes. The usage of a trail is a common way for \gls{solver} to revisit search decisions (i.e., \gls{backtrack}).}, } \newglossaryentry{trs}{ name={term rewriting system}, description={A computational model that expresses computation through the application of rewriting rules. A rewriting rule replaces the \glspl{term} on its left-hand side with the \glspl{term} on its right-hand side.}, } \newglossaryentry{unsat}{ name={unsatisfiable}, description={An \gls{instance}, or a \gls{constraint}, is unsatisfiable when a \gls{sol} cannot exist. All possible \glspl{variable-assignment} would violate at least one \gls{constraint}.}, } \newglossaryentry{variable}{ name={decision variable}, description={ A formalized decision that is yet to be made. When searching for a \gls{sol} a decision variable is said to have a certain \gls{domain}, which contains the values that the decision variable can still take. If at any point the \gls{domain} is reduced to a single value, then the decision variable is said to be \gls{fixed}. If, however, a decision variable has an empty \gls{domain}, then there does not exist a value that is consistent with the \glspl{constraint}. } } \newglossaryentry{variable-assignment}{ name={variable assignment}, description={see \gls{assignment}.}, } \newglossaryentry{violated}{ name={violated}, description={A \gls{constraint} is said to be violated when it is known that it cannot become \gls{satisfied}.}, } \newglossaryentry{zinc}{ name={Zinc}, description={The predecessor of \gls{minizinc}. In comparison to \gls{minizinc}, Zinc contained more features such as pattern matching and tuples, but was not \gls{solver}-independent.}, }