ersatz: A monad for expressing SAT or QSAT problems using observable sharing.
A monad for expressing SAT or QSAT problems using observable sharing.
For example, we can express a full-adder with:
full_adder :: Bit -> Bit -> Bit -> (Bit, Bit) full_adder a b cin = (s2, c1 || c2) where (s1,c1) = half_adder a b (s2,c2) = half_adder s1 cin
half_adder :: Bit -> Bit -> (Bit, Bit) half_adder a b = (a `xor` b, a && b)
Longer Examples
Included are a couple of examples included with the distribution.
Neither are as fast as a dedicated solver for their respective
domains, but they showcase how you can solve real world problems
involving 10s or 100s of thousands of variables and constraints
with ersatz
.
ersatz-sudoku
% time ersatz-sudoku Problem: ┌───────┬───────┬───────┐ │ 5 3 │ 7 │ │ │ 6 │ 1 9 5 │ │ │ 9 8 │ │ 6 │ ├───────┼───────┼───────┤ │ 8 │ 6 │ 3 │ │ 4 │ 8 3 │ 1 │ │ 7 │ 2 │ 6 │ ├───────┼───────┼───────┤ │ 6 │ │ 2 8 │ │ │ 4 1 9 │ 5 │ │ │ 8 │ 7 9 │ └───────┴───────┴───────┘ Solution: ┌───────┬───────┬───────┐ │ 5 3 4 │ 6 7 8 │ 9 1 2 │ │ 6 7 2 │ 1 9 5 │ 3 4 8 │ │ 1 9 8 │ 3 4 2 │ 5 6 7 │ ├───────┼───────┼───────┤ │ 8 5 9 │ 7 6 1 │ 4 2 3 │ │ 4 2 6 │ 8 5 3 │ 7 9 1 │ │ 7 1 3 │ 9 2 4 │ 8 5 6 │ ├───────┼───────┼───────┤ │ 9 6 1 │ 5 3 7 │ 2 8 4 │ │ 2 8 7 │ 4 1 9 │ 6 3 5 │ │ 3 4 5 │ 2 8 6 │ 1 7 9 │ └───────┴───────┴───────┘ ersatz-sudoku 1,13s user 0,04s system 99% cpu 1,179 total
ersatz-regexp-grid
This solves the "regular crossword puzzle" (grid.pdf) from the 2013 MIT mystery hunt.
% time ersatz-regexp-grid
ersatz-regexp-grid 2,45s user 0,05s system 99% cpu 2,502 total
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Downloads
- ersatz-0.5.tar.gz [browse] (Cabal source package)
- Package description (revised from the package)
Note: This package has metadata revisions in the cabal description newer than included in the tarball. To unpack the package including the revisions, use 'cabal get'.
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For package maintainers and hackage trustees
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Versions [RSS] | 0.1, 0.1.0.1, 0.1.0.2, 0.2, 0.2.0.1, 0.2.4, 0.2.5, 0.2.5.1, 0.2.6, 0.2.6.1, 0.3, 0.3.1, 0.4, 0.4.1, 0.4.2, 0.4.3, 0.4.4, 0.4.5, 0.4.6, 0.4.7, 0.4.8, 0.4.9, 0.4.10, 0.4.11, 0.4.12, 0.4.13, 0.5 |
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Change log | CHANGELOG.md |
Dependencies | array (>=0.2 && <0.6), attoparsec, base (>=4.9 && <5), bytestring (>=0.10.4.0 && <0.13), containers (>=0.2.0.1 && <0.8), data-default (>=0.5 && <0.9), ersatz, fail, lens (>=4 && <6), mtl (>=1.1 && <2.4), parsec (>=3.1 && <3.2), process (>=1.1 && <1.7), semigroups (>=0.16 && <1), streams (>=3.3 && <4), temporary (>=1.1 && <1.4), transformers (>=0.3 && <0.7), unordered-containers (>=0.2 && <0.3) [details] |
Tested with | ghc ==8.0.2, ghc ==8.2.2, ghc ==8.4.4, ghc ==8.6.5, ghc ==8.8.4, ghc ==8.10.7, ghc ==9.0.2, ghc ==9.2.7, ghc ==9.4.5, ghc ==9.6.2 |
License | BSD-3-Clause |
Copyright | © 2010-2015 Edward A. Kmett, © 2014-2015 Eric Mertens, © 2013 Johan Kiviniemi |
Author | Edward A. Kmett, Eric Mertens, Johan Kiviniemi |
Maintainer | Edward A. Kmett <ekmett@gmail.com> |
Revised | Revision 2 made by ryanglscott at 2024-10-26T20:07:59Z |
Category | Logic, Algorithms |
Home page | http://github.com/ekmett/ersatz |
Bug tracker | http://github.com/ekmett/ersatz/issues |
Source repo | head: git clone git://github.com/ekmett/ersatz.git |
Uploaded | by ryanglscott at 2023-09-18T10:26:28Z |
Distributions | LTSHaskell:0.5, Stackage:0.5 |
Reverse Dependencies | 3 direct, 0 indirect [details] |
Executables | ersatz-sudoku, ersatz-regexp-grid |
Downloads | 19001 total (116 in the last 30 days) |
Rating | 2.0 (votes: 1) [estimated by Bayesian average] |
Your Rating | |
Status | Docs uploaded by user Build status unknown [no reports yet] |