Oct 10, 2007, polyhedron version 0.2.1
Fixed a bug in cddlib-0.94d causing segfault when computing Vrep from a minimal number of vertices. Patched cddlib-0.94d is included.
Oct 9, 2007, polyhedron version 0.2
Made polyhedron a package. Dropped Numeric support, supporting NumPy instead. Added example.py file. The source of cddlib is now included. Using GMP is optional.
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C-Library cddlib (version 0.91) README FILE
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1. The C-library cddlib is a C implementation of the Double Description
Method of Motzkin et al. for generating all vertices (i.e. extreme points)
and extreme rays of a general convex polyhedron in R^d given by a system
of linear inequalities:
P = { x=(x1, ..., xd)^T : b - A x >= 0 }
where A is a given m x d real matrix, b is a given m-vector
and 0 is the m-vector of all zeros.
...
import
polyhedron from Python program. The package
polyhedron provides two classes Hrep and
Vrep which will hold polyhedron's data.
Currently, there is no documentation available, but the code is really
simple in order to get an idea how to access polyhedron's data from Python.
See Polyhedron.__str__ method and the header of
_cddmodule.c for more details.
Here follows an example how to construct a convex hull from a set of random points and then to test if a random point is inside or outside the hull:
from numpy import *
from polyhedron import Vrep, Hrep
points = random.random ((20,3))
def mkhull(points):
p = Vrep (points)
return Hrep (p.A, p.b)
p = mkhull(points)
print 'Hull vertices:\n',p.generators
points2 = 1.1*random.random ((3,3))
for i in range (len (points2)):
point = points2[i]
if alltrue (dot (p.A,point) <= p.b):
print 'point',point,'is IN'
else:
print 'point',point,'is OUT'
python setup.py install to build and
install polyhedron package.
Run python setup.py build_ext --inplace to build
polyhedron package in-situ.
setup.py file properly for that).