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CVExp: Controlled Vocabulary Expressions for Python
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An elegant way to represent and solve linear programming and other
optimization problems in Python.
.. NOTE:: This documentation is basically just a place holder until I have time to make it better
.. sectnum::
.. contents:: Contents
History
=======
2009-02-16 08:18:04 UTC David Baird
Version 0.1 release. Includes mixed-integer linear translation for
GLPK and lp_solve. Provided quadratic programming translation for
CVXOPT (but is missing integer translation capability, which I will
try and do sometime later).
What is CVExp?
==============
CVExp is short for "controlled vocabulary expressions." CVExp is a
Python module that allows abstract syntax trees ("expressions") to be
constructed just as easily as writing normal Python code. The names
of functions in the abstract syntax trees are based on a controlled
vocabulary, using URIs as names just like the W3C RDF does.
The intent of CVExp is that it should make it easier for developers
to integrate 3rd party libraries into Python without having to specify
entirely new APIs. Libraries and languages of particular concern are
computer algebra systems, linear programming and optimization (such as
lp_solve, GLPK, and CVXOPT), and Prolog.
Example Usage
=============
Here is an example usage to solve a mixed-integer linear programming
problem using GLPK as the backend. In order for this to work, you
obviously must install prerequisite Python packages (i.e. python-glpk or
whatever) because these are not included with CVExp::
from cvexp.builders import var
from cvexp.builders import integer
from cvexp.builders import minimize
from cvexp.translate_glpk import solve
# You could also use lp_solve by doing this:
# from cvexp.translate_lpsolve55 import solve
# ...or you could use CVXOPT like this:
# from cvexp.translate_cvxopt import solve
X = var('X') # the 'X' name is optional
Y = var('Y') # ...and so is 'Y'
# Purely linear programming:
sol = solve((
Y + 0.1 == X,
Y >= 9.8 - X,
minimize(Y),
), out_filename='problem.out') # out_filename is optional
print 'X =', sol[X] # >>> 4.95
print 'Y =', sol[Y] # >>> 4.85
# Mixed integer-linear programming:
sol = solve((
Y + 0.1 == X,
Y >= 9.8 - X,
integer(Y),
minimize(Y),
), out_filename='problem.out') # out_filename is optional
print 'X =', sol[X] # >>> 5.1
print 'Y =', sol[Y] # >>> 5
If using CVXOPT, quadratic programming problems can also be solved.
For example::
from cvexp.builders import var
from cvexp.builders import integer
from cvexp.builders import minimize
from cvexp.translate_cvxopt import solve
X = var()
Y = var()
sol = solve((
minimize((X - 5) ** 2 + (Y - 3) ** 2),
))
print 'X =', sol[X] # >>> 5.0
print 'Y =', sol[Y] # >>> 3.0
Download
========
Latest release:
- `cvexp-0.1.tar.gz `_
- `cvexp-0.1-py2.5.egg `_
- `cvexp-0.1.win32.exe `_
Bazaar repository::
bzr clone http://www.aclevername.com/projects/cvexp