ANN: python-constraint 1.0
Overview
**python-constraint** [1]_ is a Python module offering solvers for
Constraint Solving Problems (CSPs) over finite domains in simple
and pure Python. CSP is class of problems which may be represented
in terms of variables (`a`, `b`, ...), domains (`a in [1, 2, 3]`, ...),
and constraints (`a b`, ...).
. [1] http://codespeak.net/~niemeyer/constraint/
Examples
Basic
-
Here is a basic interactive example::
from constraint import *
problem = Problem()
problem.addVariable(a, [1,2,3])
problem.addVariable(b, [4,5,6])
problem.getSolutions()
[{'a': 3, 'b': 6}, {'a': 3, 'b': 5}, {'a': 3, 'b': 4},
{'a': 2, 'b': 6}, {'a': 2, 'b': 5}, {'a': 2, 'b': 4},
{'a': 1, 'b': 6}, {'a': 1, 'b': 5}, {'a': 1, 'b': 4}]
problem.addConstraint(lambda a, b: a*2 == b,
(a, b))
problem.getSolutions()
[{'a': 3, 'b': 6}, {'a': 2, 'b': 4}]
problem = Problem()
problem.addVariables([a, b], [1, 2, 3])
problem.addConstraint(AllDifferentConstraint())
problem.getSolutions()
[{'a': 3, 'b': 2}, {'a': 3, 'b': 1}, {'a': 2, 'b': 3},
{'a': 2, 'b': 1}, {'a': 1, 'b': 2}, {'a': 1, 'b': 3}]
Rooks
-
Here is an example solving the classical rooks problem::
problem = Problem()
numpieces = 8
cols = range(numpieces)
rows = range(numpieces)
problem.addVariables(cols, rows)
for col1 in cols:
for col2 in cols:
if col1 col2:
problem.addConstraint(lambda row1, row2: row1 != row2,
(col1, col2))
solutions = problem.getSolutions()
Magic squares
-
And here is an example solving a 4x4 magic square::
problem = Problem()
problem.addVariables(range(0, 16), range(1, 16+1))
problem.addConstraint(AllDifferentConstraint(), range(0, 16))
problem.addConstraint(ExactSumConstraint(34), [0,5,10,15])
problem.addConstraint(ExactSumConstraint(34), [3,6,9,12])
for row in range(4):
problem.addConstraint(ExactSumConstraint(34),
[row*4+i for i in range(4)])
for col in range(4):
problem.addConstraint(ExactSumConstraint(34),
[col+4*i for i in range(4)])
solutions = problem.getSolutions()
Features
The following solvers are available:
- Backtracking solver
- Recursive backtracking solver
- Minimum conflicts solver
Predefined constraint types currently available:
- FunctionConstraint
- AllDifferentConstraint
- AllEqualConstraint
- ExactSumConstraint
- MaxSumConstraint
- MinSumConstraint
- InSetConstraint
- NotInSetConstraint
- SomeInSetConstraint
- SomeNotInSetConstraint
-
Documentation
-
There's documentation for the module at:
- http://codespeak.net/~niemeyer/constraint/doc/
Download
**python-constraint** may be found at the following
address:
- http://codespeak.net/~niemeyer/constraint/files/
-
Subversion repository
-
Available at:
- http://codespeak.net/svn/user/niemeyer/constraint/
--
Gustavo Niemeyer
http://niemeyer.net
--
http://mail.python.org/mailman/listinfo/python-list
ANN: python-constraint 1.0
Overview
**python-constraint** [1]_ is a Python module offering solvers for
Constraint Solving Problems (CSPs) over finite domains in simple
and pure Python. CSP is class of problems which may be represented
in terms of variables (`a`, `b`, ...), domains (`a in [1, 2, 3]`, ...),
and constraints (`a b`, ...).
.. [1] http://codespeak.net/~niemeyer/constraint/
Examples
Basic
-
Here is a basic interactive example::
from constraint import *
problem = Problem()
problem.addVariable(a, [1,2,3])
problem.addVariable(b, [4,5,6])
problem.getSolutions()
[{'a': 3, 'b': 6}, {'a': 3, 'b': 5}, {'a': 3, 'b': 4},
{'a': 2, 'b': 6}, {'a': 2, 'b': 5}, {'a': 2, 'b': 4},
{'a': 1, 'b': 6}, {'a': 1, 'b': 5}, {'a': 1, 'b': 4}]
problem.addConstraint(lambda a, b: a*2 == b,
(a, b))
problem.getSolutions()
[{'a': 3, 'b': 6}, {'a': 2, 'b': 4}]
problem = Problem()
problem.addVariables([a, b], [1, 2, 3])
problem.addConstraint(AllDifferentConstraint())
problem.getSolutions()
[{'a': 3, 'b': 2}, {'a': 3, 'b': 1}, {'a': 2, 'b': 3},
{'a': 2, 'b': 1}, {'a': 1, 'b': 2}, {'a': 1, 'b': 3}]
Rooks
-
Here is an example solving the classical rooks problem::
problem = Problem()
numpieces = 8
cols = range(numpieces)
rows = range(numpieces)
problem.addVariables(cols, rows)
for col1 in cols:
for col2 in cols:
if col1 col2:
problem.addConstraint(lambda row1, row2: row1 != row2,
(col1, col2))
solutions = problem.getSolutions()
Magic squares
-
And here is an example solving a 4x4 magic square::
problem = Problem()
problem.addVariables(range(0, 16), range(1, 16+1))
problem.addConstraint(AllDifferentConstraint(), range(0, 16))
problem.addConstraint(ExactSumConstraint(34), [0,5,10,15])
problem.addConstraint(ExactSumConstraint(34), [3,6,9,12])
for row in range(4):
problem.addConstraint(ExactSumConstraint(34),
[row*4+i for i in range(4)])
for col in range(4):
problem.addConstraint(ExactSumConstraint(34),
[col+4*i for i in range(4)])
solutions = problem.getSolutions()
Features
The following solvers are available:
- Backtracking solver
- Recursive backtracking solver
- Minimum conflicts solver
Predefined constraint types currently available:
- FunctionConstraint
- AllDifferentConstraint
- AllEqualConstraint
- ExactSumConstraint
- MaxSumConstraint
- MinSumConstraint
- InSetConstraint
- NotInSetConstraint
- SomeInSetConstraint
- SomeNotInSetConstraint
-
Documentation
-
There's documentation for the module at:
- http://codespeak.net/~niemeyer/constraint/doc/
Download
**python-constraint** may be found at the following
address:
- http://codespeak.net/~niemeyer/constraint/files/
-
Subversion repository
-
Available at:
- http://codespeak.net/svn/user/niemeyer/constraint/
--
Gustavo Niemeyer
http://niemeyer.net
--
http://mail.python.org/mailman/listinfo/python-list
Re: ANN: python-constraint 1.0
Gustavo Niemeyer ha scritto: Overview **python-constraint** [1]_ is a Python module offering solvers for Constraint Solving Problems (CSPs) over finite domains in simple and pure Python. CSP is class of problems which may be represented in terms of variables (`a`, `b`, ...), domains (`a in [1, 2, 3]`, ...), and constraints (`a b`, ...). This sound cool, but have you noticed logilab.constraint? Care to contrast? -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: python-constraint 1.0
Gustavo Niemeyer wrote: **python-constraint** [1]_ is a Python module offering solvers for Constraint Solving Problems (CSPs) over finite domains in simple and pure Python. Very cool! I can't wait to get some time to play with this. -- Benji York -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: python-constraint 1.0
On Thu, Jul 07, 2005 at 03:40:10AM -0300, Gustavo Niemeyer wrote: Overview **python-constraint** [1]_ is a Python module offering solvers for Constraint Solving Problems (CSPs) over finite domains in simple and pure Python. CSP is class of problems which may be represented in terms of variables (`a`, `b`, ...), domains (`a in [1, 2, 3]`, ...), and constraints (`a b`, ...). .. [1] http://codespeak.net/~niemeyer/constraint/ People interested in CSP and python may also want to check Logilab's constraint module which has been available from some time at: http://www.logilab.org/projects/constraint/ Gustavo, maybe we should coordinate and merge our efforts? -- Alexandre Fayolle LOGILAB, Paris (France). http://www.logilab.com http://www.logilab.fr http://www.logilab.org signature.asc Description: Digital signature -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: python-constraint 1.0
Hello Alexandre, People interested in CSP and python may also want to check Logilab's constraint module which has been available from some time at: http://www.logilab.org/projects/constraint/ Indeed! And please send us some notes comparing both. :-) The AIMA book inspired me to write that module. IIRC, there's also some kind of constraint code in Python by one of the book authors (Peter Norvig). For those who are interested, chapter 5, which talks about CSPs, may be found in the web site. Gustavo, maybe we should coordinate and merge our efforts? Probably. I confess that even though I'm using CSP logic on other real world projects, I wrote that module completely for fun, and was not really caring if I was reinventing the wheel or not. Alexandre Fayolle LOGILAB, Paris (France). I'm currently in Paris, btw. -- Gustavo Niemeyer http://niemeyer.net -- http://mail.python.org/mailman/listinfo/python-list
