Search results
Results From The WOW.Com Content Network
Backtracking is a class of algorithms for finding solutions to some computational problems, notably constraint satisfaction problems, that incrementally builds candidates to the solutions, and abandons a candidate ("backtracks") as soon as it determines that the candidate cannot possibly be completed to a valid solution.
The GNU Prolog program below resolved a 100 queens problem in less than a tenth of a second. is meaningless without a frame of reference. Giving at least the processor used for the test and the time of a slower algorithm would help matters greatly. Andrew J. MacDonald 03:51, 30 November 2006 (UTC)
Prolog implementations usually omit the occurs check for reasons of efficiency, which can lead to circular data structures and looping. By not performing the occurs check, the worst case complexity of unifying a term with term is reduced in many cases from (() + ()) to (((), ())); in the particular, frequent case of variable-term unifications, runtime shrinks to ().
The eight queens puzzle is the problem of placing eight chess queens on an 8×8 chessboard so that no two queens threaten each other; thus, a solution requires that no two queens share the same row, column, or diagonal. There are 92 solutions.
This is called a green cut operator.The ! tells the interpreter to stop looking for alternatives; however, if gotmoney(X) fails it will check the second rule. Although checking for gotmoney(X) in the second rule may appear redundant since Prolog's appearance is dependent on gotmoney(X) failing before, otherwise the second rule would not be evaluated in the first place.
Animation of min-conflicts resolution of 8-queens. First stage assigns columns greedily minimizing conflicts, then solves. Min-Conflicts solves the N-Queens Problem by selecting a column from the chess board for queen reassignment. The algorithm searches each potential move for the number of conflicts (number of attacking queens), shown in each ...
This generates sentences such as "the cat eats the bat", "a bat eats the cat". One can generate all of the valid expressions in the language generated by this grammar at a Prolog interpreter by typing sentence(X,[]). Similarly, one can test whether a sentence is valid in the language by typing something like sentence([the,bat,eats,the,bat],[]).
In 1983, David H. D. Warren designed an abstract machine for the execution of Prolog consisting of a memory architecture and an instruction set. [ 1 ] [ 2 ] [ 3 ] This design became known as the Warren Abstract Machine (WAM) and has become the de facto standard target for Prolog compilers .