https://github.com/erohkohl/n-queens-sat

Modelling n-queens problem as conjunctive normal form and solving it with DPLL algorithm. This project should made me familiar with Rust and the test driven approach.
https://github.com/erohkohl/n-queens-sat

constraint-programming constraint-satisfaction-problem dpll-algorithm n-queens rust rust-lang sat-solver tdd

Last synced: 1 day ago
JSON representation

Modelling n-queens problem as conjunctive normal form and solving it with DPLL algorithm. This project should made me familiar with Rust and the test driven approach.

• Host: GitHub
• URL: https://github.com/erohkohl/n-queens-sat
• Owner: erohkohl
• Created: 2017-06-24T18:30:37.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2017-07-20T19:00:58.000Z (over 7 years ago)
• Last Synced: 2024-05-22T22:33:07.863Z (6 months ago)
• Topics: constraint-programming, constraint-satisfaction-problem, dpll-algorithm, n-queens, rust, rust-lang, sat-solver, tdd
• Language: Rust
• Homepage:
• Size: 16.3 MB
• Stars: 7
• Watchers: 5
• Forks: 1
• Open Issues: 5
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

• awesome-rust-formalized-reasoning - n-queens-sat - modelling n-queens problem as conjunctive normal form and solving it with DPLL algorithm. (Unclassified / Libraries)

README

        
Modelling n-queens problem as propositional formula and solve it with DPLL 

------------

[![Build Status](https://travis-ci.org/erohkohl/n-queens-sat.svg?branch=master)](https://travis-ci.org/erohkohl/n-queens-sat) [![codecov](https://codecov.io/gh/erohkohl/n-queens-sat/branch/master/graph/badge.svg)](https://codecov.io/gh/erohkohl/n-queens-sat)

This project provides a simple implementation of the *Davis, Putnam, Logemann* and *Loveland* algorithm 

(see [DPLL](https://en.wikipedia.org/wiki/DPLL_algorithm)) in the modern systems programming language 

[Rust](https://www.rust-lang.org/en-US/). The DPLL algorithm decides whether a propositional 

formula in *conjunctive normal form* (CNF) is satisfiable and returns a satisfiable assignment. Therefore it extends the 

depth first search with *unit propagation* (UP), if a literal must be true in the current partial assignment. You

can find my implementation of the DPLL algorithm in the Rust-file 

[src/logic/sat.rs](https://github.com/erohkohl/n-queens-sat/blob/master/src/logic/sat.rs). Furthermore the file 

[src/model/n_queens.rs](https://github.com/erohkohl/n-queens-sat/blob/master/src/model/n_queens.rs) 

contains the modelling of the n-queens problem as propositional formula. The following listing shows one possible

solution of the four-queens problem.

```bash

. Q . . 

. . . Q 

Q . . . 

. . Q . 

```

This implementation is not able to solve six-queens problem in acceptable time, because it's

data structures and UP is not fast enough.

#### Future work

- Improve performance of UP and data structures to solve eight-queens problem in appropriate time

- Add *Conflict-Driven Clause Learning* (see [CDCL](https://en.wikipedia.org/wiki/Conflict-Driven_Clause_Learning)) 

to DPLL algorithm