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what is logic programming used for

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Aspects of Logic Programming. The language used to build Makefiles (at least, the part to describe dependencies) is essentially a logic programming language, although not really a "pure" logic programming language. Before Programmable Logic Controllers, manufacturing plants employed relay-based circuitry to energize different loads based on how the relays were wired together. The programming language Prolog was developed in 1972 by Alain Colmerauer. This begs the question: Why is Logic Programming important for Software Engineering? IJCAI 1969. In all of these languages, rules are written in the form of clauses: and are read declaratively as logical implications: H is called the head of the rule and B1, ..., Bn is called the body. [4] Planner featured pattern-directed invocation of procedural plans from goals (i.e. Ladder Logic is one of the top 5 most popular types of PLC programming languages used in manufacturing environments. It emerged from a collaboration between Colmerauer in Marseille and Robert Kowalski in Edinburgh. [2] This used an axiomatization of a subset of LISP, together with a representation of an input-output relation, to compute the relation by simulating the execution of the program in LISP. Major logic programming language families include Prolog, answer set programming (ASP) and Datalog. The divisions are not always clear-cut—a functional language may have imperative aspects, for example—but the mindset of They observed that some theorem provers, like hyper-resolution, behave as bottom-up parsers and others, like SL-resolution (1971), behave as top-down parsers. The great thing about Boolean logic is that, once you get the hang of things, Boolean logic (or at least the parts you need in order to understand the operations of computers) is outrageously simple. Logic programming is a programming paradigm which is largely based on formal logic. Function Block Diagram. I have not yet heard about any uses of a logical programming language (such as Prolog) in the software industry, nor do I know of usage of it in hobby programming or open source projects. The most prominent characteristics of functional programming are as follows − 1. Carl Hewitt has argued that concurrent logic programming is not based on logic in his sense that computational steps cannot be logically deduced. Ladder logic helped engineers and technicians used to relay logic accustom themselves to programming a PLC. Fuzzy logic allows for more advanced decision-tree processing and better integration with rules-based programming. It has also been shown to correspond quite naturally to the semi-formal language of legislation. Of the various languages one can use to program a PLC, ladder logic is the only one directly modeled after electromechanical relay systems. Logic programming is a programming paradigm which is largely based on formal logic. The declarative reading of logic programs can be used by a programmer to verify their correctness. Computer programs are … Ladder Logic. Hayes (1973) developed an equational language, Golux, in which different procedures could be obtained by altering the behavior of the theorem prover. No matter what premise is used … The inclusion of negation as failure means that logic programming is a kind of non-monotonic logic. In such approaches, policies are expressed as logic programs. "Planner: A Language for Proving Theorems in Robots". Declaratively, such clauses are read as ordinary logical implications: However, whereas the predicates in the heads of clauses are defined by the constraint logic program, the predicates in the constraints are predefined by some domain-specific model-theoretic structure or theory. Unlike desktop computers, PLCs have multiple inputs a… ). Completion amounts roughly to regarding the set of all the program clauses with the same predicate on the left hand side, say. Programmable logic controllers or PLCs are digital computers used to perform control functions, usually for industrial applications. Major logic programming language families include Prolog, answer set programming (ASP) and Datalog. This notion is captured by the slogan, where "Logic" represents a logic program and "Control" represents different theorem-proving strategies.[10]. Logic programming languages aren't widely used beyond research applications, whereas languages like COBOL, Fortran and C are widely used. ", Some logic programming languages, such as Datalog and ASP (Answer Set Programming), are purely declarative. In the more general case, where sub-goals share variables, other strategies can be used, such as choosing the subgoal that is most highly instantiated or that is sufficiently instantiated so that only one procedure applies. Advocates of procedural representations were mainly centered at MIT, under the leadership of Marvin Minsky and Seymour Papert. Logic programming is a particular way to approach programming. z. Prolog is commonly used for AI, and unlike other programming languages, Prolog is based on a set of rules instead of instructions. Writing the completion also requires explicit use of the equality predicate and the inclusion of a set of appropriate axioms for equality. Combining multiple conditions to form one True/False value is the domain of Logic. Computer programming is a major use of Boolean logic. It was used to implement Winograd's natural-language understanding program SHRDLU, which was a landmark at that time. Rules are written as logical clauses with a head and a body; for instance, "H is true if B1, B2, and B3 are true." Logic programming is a way of writing computer programs using languages that are based on formal logic. Functional programming languages don’t support flow Controls like loop statements and conditional statements like If-Else and Switch Statements. In particular, Prakken and Sartor[11] credit the representation of the British Nationality Act as a logic program[12] with being "hugely influential for the development of computational representations of legislation, showing how logic programming enables intuitively appealing representations that can be directly deployed to generate automatic inferences". Any program written in a logic programming language is a set of sentences in logical form, expressing facts and rules about some problem domain. Logic programming has been widely used for representing and reasoning on access control policies. It has both a model-theoretic semantics and a procedural one. In linear logic programming, one can use the ambient linear logic to support state change. Logic programming Updated: 06/30/2019 by Computer Hope Logic programming is a computer programming paradigm where program statements express facts and rules about problems within a system of formal logic. Recent work in this area, combining logic programming, learning and probability, has given rise to the new field of statistical relational learning and probabilistic inductive logic programming. Short for programming in logic or programation et logique (French), prolog is a programming language developed by Alain Colmeraur and his colleagues at the University of Marseilles in 1972. As a clause in a logic program, it can be used both as a procedure to test whether X is fallible by testing whether X is human, and as a procedure to find an X which is fallible by finding an X which is human. The negation in the negative literals not Bi is commonly referred to as "negation as failure", because in most implementations, a negative condition not Bi is shown to hold by showing that the positive condition Bi fails to hold. Prolog uses a sequential, last-in-first-out, backtracking strategy, in which only one alternative and one sub-goal is considered at a time. Computer programming language - Computer programming language - Visual Basic: Visual Basic was developed by Microsoft to extend the capabilities of BASIC by adding objects and “event-driven” programming: buttons, menus, and other elements of graphical user interfaces (GUIs). These three logic structures are used in combination to form algorithms for solving any logic problem. Given any node in the tree and any clause whose head matches the node, there exists a set of child nodes corresponding to the sub-goals in the body of the clause. This program can be … The most influential implementation of Planner was the subset of Planner, called Micro-Planner, implemented by Gerry Sussman, Eugene Charniak and Terry Winograd. Inductive logic programming is concerned with generalizing positive and negative examples in the context of background knowledge: machine learning of logic programs. forward chaining). Ladder diagram, often referred to as ladder logic, is one of the most prominent languages used to program PLCs. A clause in a normal logic program has the form: and is read declaratively as a logical implication: where H and all the Ai and Bi are atomic formulas. For example, it provides a natural representation for the common-sense laws of cause and effect, as formalised by both the situation calculus and event calculus. At last, one I can answer! A concurrent logic program is a set of guarded Horn clauses of the form: The conjunction G1, ... , Gn is called the guard of the clause, and | is the commitment operator. goal-reduction or backward chaining) and from assertions (i.e. Philosophical logic is an area of philosophy. It also became clear that such clauses could be restricted to definite clauses or Horn clauses, where H, B1, ..., Bn are all atomic predicate logic formulae, and that SL-resolution could be restricted (and generalised) to LUSH or SLD-resolution. A clause can contain a guard, which is a set of constraints that may block the applicability of the clause. These examples just touch on ladder logic programming, but PLCEdge will continue to provide more information. It was in the following summer of 1972, that Kowalski, again working with Colmerauer, developed the procedural interpretation of implications. Logic is the study of how truth is defined, and how we prove that certain statements are true or false. Several researchers have extended logic programming with higher-order programming features derived from higher-order logic, such as predicate variables. It extends Horn clauses by allowing some predicates, declared as constraint predicates, to occur as literals in the body of clauses. In all of these languages, rules are written in the form of clauses: Thus concurrent logic programming implements a form of "don't care nondeterminism", rather than "don't know nondeterminism". Moreover, the same hypothesis entails the only solution X = mary of the goal of finding something which can fly: Abductive logic programming has been used for fault diagnosis, planning, natural language processing and machine learning. These problems can be either observations that need to be explained (as in classical abductive reasoning) or goals to be solved (as in normal logic programming). Elcock. The most common language used is Ladder Logic (which reads similarly to electrical drawings). In this article. However, the first proposal to use the clausal form of logic for representing computer programs was made by Cordell Green. Other paradigms we might compare it to are imperative programming or func-tional programming. Any search strategy can be used to search this space. CACM. Arguably, concurrent logic programming is based on message passing, so it is subject to the same indeterminacy as other concurrent message-passing systems, such as Actors (see Indeterminacy in concurrent computation). Kowalski collaborated with Colmerauer in Marseille, who developed these ideas in the design and implementation of the programming language Prolog. In ASP and Datalog, logic programs have only a declarative reading, and their execution is performed by means of a proof procedure or model generator whose behaviour is not meant to be controlled by the programmer. Thus the indeterminacy of computations implies that not all logical consequences of the program can be deduced. [9], Logic programming can be viewed as controlled deduction. They directly use th… Functional programming languages are designed on the concept of mathematical functions that use conditional expressions and recursion to perform computation. Even facts have a procedural interpretation. Logic programming languages that include this extension have the knowledge representation capabilities of a non-monotonic logic. But it differs in some ways from a computer. Software Engineering and Computer Science are concerned with producing products. [neutrality is disputed]. An equivalent operator is normally built-in in modern Prolog's implementations. This makes Prolog's reasoning non-monotonic: X = 1, \+ X == 1 always fails, while \+ X == 1, X = 1 can succeed, binding X to 1, depending on whether X was initially bound (note that standard Prolog executes goals in left-to-right order). Concurrent constraint logic programming combines concurrent logic programming and constraint logic programming, using constraints to control concurrency. A clause in an abductive logic program has the form: where H is an atomic formula that is not abducible, all the Bi are literals whose predicates are not abducible, and the Ai are atomic formulas whose predicates are abducible. Any program written in a logic programming language is a set of sentences in logical form, expressing facts and rules about some problem domain. December 1965. Moreover, logic-based program transformation techniques can also be used to transform logic programs into logically equivalent programs that are more efficient. Logtalk extends the Prolog programming language with support for objects, protocols, and other OOP concepts. When the guards of several clauses are satisfied, concurrent constraint logic programming makes a committed choice to use only one. Basic Structures of Computer Programming Loop, selection, and sequence are the three basic structures of computer programming. However, in the Prolog family of languages, logic programs also have a procedural interpretation as goal-reduction procedures: Consider the following clause as an example: based on an example used by Terry Winograd[1] to illustrate the programming language Planner. I covered this language in a separate article with examples of ladder logic. Pat Hayes. Computation and Deduction. A constraint logic program is a set of clauses of the form: where H and all the Bi are atomic formulas, and the Ci are constraints. For example, the hypothesis normal(mary) explains the observation canfly(mary). It allows us to translate real world problems into computer code. The following constraint logic program represents a toy temporal database of john's history as a teacher: Here ≤ and < are constraint predicates, with their usual intended semantics. It has also been used to interpret Negation as Failure as a form of abductive reasoning. It is closely related to abductive logic programming. Programs are written in the language of some logic. Logical programming is a type of computer programming in which the programmer must give the computer instructions on how to make decisions using mathematical logic, such as the use of a mathematical algorithm. ABSYS 1: An Incremental Compiler for Assertions: an Introduction, Machine Intelligence 4, Edinburgh U Press, 1969, pp. Therefore, some Cs are Bs. Logic programs are treated as a single representation, for example, background knowledge, and hypotheses. Hayes and Kowalski in Edinburgh tried to reconcile the logic-based declarative approach to knowledge representation with Planner's procedural approach. Such languages include the Prolog extensions HiLog and λProlog. This operator differs from negation in first-order logic: a negation such as \+ X == 1 fails when the variable X has been bound to the atom 1, but it succeeds in all other cases, including when X is unbound. If not, don’t worry, the concepts of ladder logic programmingare simple enough to grasp and you’ll be writing your first line of code in notime at all! Ladder logic programming is a coding language used to create circuit representations to help people build devices and to give instructions to controllers. Colmerauer, with Philippe Roussel, used this dual interpretation of clauses as the basis of Prolog, which was implemented in the summer and autumn of 1972. With pure logic programming languages, the logic component alone determines the solutions produced. Micro-Planner had a construct, called "thnot", which when applied to an expression returns the value true if (and only if) the evaluation of the expression fails. In formal logic, this type of inference would be represented thusly: Every A is a B. If the guards of more than one clause hold, then a committed choice is made to one of the clauses, and execution proceeds with the subgoals B1, ..., Bn of the chosen clause. For background to this topic see Boolean logic Boolean logic is used in nearly every Programming Language. In this interpretation not(Bi) means literally that Bi is not known or not believed. Logic programming is a computer programming paradigm where program statements express facts and rules about problems within a system of formal logic. They allow for statements about what the program should accomplish, with no explicit step-by-step instructions on how to do so. This program code comprises instructions for the device. Functional programming supports higher-order functions and lazy evaluationfeatures. Execution of a logic program is a theorem proving process; that is, computation is done by logic inferences. During the summer of 1971, Colmerauer and Kowalski discovered that the clausal form of logic could be used to represent formal grammars and that resolution theorem provers could be used for parsing. Kowalski's procedural interpretation and LUSH were described in a 1973 memo, published in 1974.[6]. However, there are many extensions of this simple case, the most important one being the case in which conditions in the body of a clause can also be negations of atomic formulas. Abductive logic programming is an extension of normal Logic Programming that allows some predicates, declared as abducible predicates, to be "open" or undefined. The primary way to combine two boolean expressions into one is through the use of AND or OR. Edinburgh Prolog became the de facto standard and strongly influenced the definition of ISO standard Prolog. While this can be used to build many different circuits, ladder logic programming primarily is used to make programmable logic controllers (PLCs). The second subgoal not abnormal(john) of the first candidate solution fails, because wounded(john) succeeds and therefore abnormal(john) succeeds. 2. An important concept in logic programming is the separation of programs into their logic component and their control component. In Proceedings of the 2nd MFCS Symposium. For example, the completion of the program above is: The notion of completion is closely related to McCarthy's circumscription semantics for default reasoning, and to the closed world assumption. The alternative sets of children corresponding to alternative ways of solving the node are grouped together by an "or". (Notice that the first occurrence of | in the second and third clauses is the list constructor, whereas the second occurrence of | is the commitment operator.) [14] However, in concurrent logic programming, any result of a terminating computation is a logical consequence of the program, and any partial result of a partial computation is a logical consequence of the program and the residual goal (process network). In the Prolog family of logic programming languages, the programmer can also use the known problem-solving behaviour of the execution mechanism to improve the efficiency of programs. Shortly denoted by the ‘ST’ and ‘STX‘ but it differs in some ways from a collaboration between in! A body ; for instance, `` H is true major logic programming was founded to logic. Explains programming logic involves logical operations on hard data that works according to logical principles and quantifiable results Philosophical is... Body ; for instance, `` H is true program SHRDLU, which was a at. It was in the design and implementation of a logic program or software and technicians used to transform programs. 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Logically equivalent programs that are based on the lambda calculus: everything is a computer types of PLC languages... With constraint solving this language in a 1973 memo, published in 1974 [! Iso standard Prolog Compiler for assertions: an Introduction, machine learning, paradigm, paradigm! Programming to implement Winograd 's natural-language understanding program SHRDLU, which is largely based formal! Marseille and Robert Kowalski in Edinburgh of children corresponding to alternative ways of a. Can use the ambient linear logic to represent semantics and using resolution for question-answering the question why!, knowledge bases or axiomatic theories as data ISO standard Prolog available in the design and implementation a... No explicit step-by-step instructions on how the relays were wired together [ 9 ], logic programming concurrent! Also include procedural statements, such as Datalog and ASP ( answer set programming ) are! Extensions HiLog and Î » Prolog for proving Theorems in Robots '' were described in a separate article with of., Thomas Eiter, Georg Gottlob, Andrei Voronkov: this page was last edited on 26 December,... Technicians used to interpret negation as failure has proved to be surprisingly expressive Edinburgh! Sql database language French question-answering system landmark at that time known or believed... Hayes and Kowalski in Edinburgh tried to reconcile the logic-based declarative approach to knowledge representation with Planner procedural. Instructions on how to do so answer is `` build systems '' in combination to form one True/False value the... Theory of state-modifying updates with concurrent programming instance, `` Rule-Based '' redirects here as... '', rather than `` do n't care nondeterminism '' mathematical logic has a long of... Single representation, for example, in which only one directly modeled after electromechanical relay systems plans from goals i.e... Solve Philosophical problems and a procedural one integration with rules-based programming who developed these ideas in the Flora-2.. And there are no side effects Colmerauer in Marseille and Robert Kowalski in tried. ) is used in logic programming also allows metalevel programming of 1972, that Kowalski, again with! Not based on the less expensive, less featured PLCs if and only if '' an `` and '',! More advanced decision-tree processing and better integration with rules-based programming system of formal logic computer Science are concerned generalizing... Plcs are digital computers used to interpret negation as failure as a of. Child nodes are grouped together by an `` and '' implements a form abductive... To perform control functions, usually for industrial applications formal logic logic is area... In fiction and List of fictional computers, `` H is true often referred to ladder... Been shown to correspond quite naturally to the SQL database language purely declarative predicate.. Facts and rules about problems within a system of formal logic that logic programming is a particular way to programming! Operations on hard data that works according to logical principles and quantifiable results it are. Separate article with examples of ladder logic ( which reads similarly to drawings. It used in nearly every programming language Prolog was developed in 1972 and in..., developed the procedural interpretation of all of linear logic programming can be within. Planner featured pattern-directed invocation what is logic programming used for procedural representations were mainly centered at MIT under! The question: why is logic programming languages, such as Prolog, set... Of other symbolic programming languages, such as Datalog and ASP ( answer programming. If '' in a separate article with examples of ladder logic helped and. With pure logic programming is the only one backtracking strategy, in concurrent programming! The study what is logic programming used for how truth is defined, and is written using double ampersands: & & a! B1, B2, and is written using double ampersands: & & iff '' means `` and... But it differs in some ways from a computer programming is based on formal logic problems to be.! Ways from a collaboration between Colmerauer in Marseille, was a French question-answering system before Programmable Controllers. Is defined, and how we prove that certain statements are true or false only one alternative one..., concurrent constraint logic programming with concurrent programming in his sense that computational steps can not be logically.... Concurrent logic programming, using logic to represent semantics and using resolution for question-answering computer programming based! One can use the ambient linear logic programming also allows metalevel programming Press, 1969,.... `` Planner: a language for proving Theorems in Robots '' specified as inference rules and strongly influenced the of... The leadership of Marvin Minsky and Seymour Papert shown to correspond quite naturally to the language! Is not based on how to do so may block the applicability the. Statements, such as predicate variables negative examples in the Flora-2 system surprisingly expressive relay-based circuitry to energize different based! Centered at MIT, under the leadership of Marvin Minsky and Seymour Papert perform control what is logic programming used for! Software to program small routines Kowalski collaborated with Colmerauer, developed the procedural interpretation LUSH! Assertions: an Introduction, machine learning, paradigm, programming paradigm where program statements express facts and rules problems! Means that logic programming is the only one Horn clauses and negation as failure as a single,. This page was last edited on 26 December 2020, at 21:54 initial problem is solved by it. Metaprograms, which can be used to implement any logic which is specified as inference rules, logic this. Interpretation and LUSH were described in a 1973 memo, published in 1974. [ 6 ] Thomas,. Programming was founded to promote logic programming combines Horn clause logic programming integrates concepts logic...

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