On Mon, Feb 3, 2020 at 2:49 PM Murad Tukan <murad...@gmail.com> wrote:
>
> This actually works fine. Why when running with 2 digit floating points, the
> code doesn't run? Is there any way to make it work with floats??
it's not documented properly, but looking at the source (e.g. by doing
VoronoiDiagram??)
tells you that
raise NotImplementedError('Base ring of the Voronoi diagram must '
'be one of QQ, RDF, AA.')
Thus if Sage encounters floating point input there, it uses RDF (Real
Double Float, i.e. the usual x86_64 double).
This is not very robust. I guess the algorithm in Sage is a native one.
You might try scipy's
https://docs.scipy.org/doc/scipy-0.18.1/reference/generated/scipy.spatial.Voronoi.html
perhaps it's more efficient if you must use floats.
>
> On Monday, 3 February 2020 16:15:57 UTC+2, Matthias Koeppe wrote:
>>
>> Try if it works if you use rationals (-48/100) instead of floats (-0.48).
>>
>> On Monday, February 3, 2020 at 8:48:34 AM UTC-5, Murad Tukan wrote:
>>>
>>> Dear all,
>>>
>>>
>>> Computer info:
>>> CPU: i7-6500U @ 2.50GHZ
>>> Memory: 16.0GB
>>>
>>> Sage information: SageMath 9.0 (Windows, installed using the .exe file),
>>> and even on Linux version.
>>>
>>> Platforms ran at: SageMath 9.0 Shell, SageMath 9.0 Notebook, From Python
>>> script (and then running the command sage -python "script_name.py").
>>>
>>> Description of problem:
>>>
>>> When running the following code:
>>>
>>> P = [[-0.48, 0.83], [-5.33, 9.23]]
>>> Q = [[0.43, 0. ], [9.04, 0. ]]
>>> Z = [[-0.35, -0.60], [-1.44, -2.49]]
>>>
>>> V = VoronoiDiagram(P)
>>> R = [r for r in V.regions().items()]
>>> s = R[0][1].hyperplane_arrangement()
>>>
>>> V = VoronoiDiagram(Q)
>>> R = [r for r in V.regions().items()]
>>> s = s.add_hyperplane(R[0][1].hyperplane_arrangement())
>>>
>>> V = VoronoiDiagram(Z)
>>> R = [r for r in V.regions().items()]
>>> s = s.add_hyperplane(R[0][1].hyperplane_arrangement())
>>>
>>> s.regions()
>>>
>>> Sage fails to compute the regions which is weird since it can compute the
>>> vertices which means that there is even a bounded region (in my case). When
>>> running the same code on SageMathCell, It is computed smoothly while on my
>>> machine it is not!
>>>
>>> The full traceback I get is:
>>>
>>> ---------------------------------------------------------------------------
>>> ValueError Traceback (most recent call last)
>>> <ipython-input-6-4ba993d8025f> in <module>()
>>> ----> 1 s.regions()
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/misc/cachefunc.pyx
>>> in sage.misc.cachefunc.CachedMethodCallerNoArgs.__call__
>>> (build/cythonized/sage/misc/cachefunc.c:12712)()
>>> 2308 if self.cache is None:
>>> 2309 f = self.f
>>> -> 2310 self.cache = f(self._instance)
>>> 2311 return self.cache
>>> 2312
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/geometry/hyperplane_arrangement/arrangement.py
>>> in regions(self)
>>> 1608 R = self.base_ring()
>>> 1609 dim = self.dimension()
>>> -> 1610 universe = Polyhedron(eqns=[[0] + [0] * dim], base_ring=R)
>>> 1611 regions = [universe]
>>> 1612 for hyperplane in self:
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/geometry/polyhedron/constructor.py
>>> in Polyhedron(vertices, rays, lines, ieqs, eqns, ambient_dim, base_ring,
>>> minimize, verbose, backend)
>>> 660 if got_Vrep:
>>> 661 Vrep = [vertices, rays, lines]
>>> --> 662 return parent(Vrep, Hrep, convert=convert, verbose=verbose)
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/structure/parent.pyx
>>> in sage.structure.parent.Parent.__call__
>>> (build/cythonized/sage/structure/parent.c:9245)()
>>> 900 return mor._call_(x)
>>> 901 else:
>>> --> 902 return mor._call_with_args(x, args, kwds)
>>> 903
>>> 904 raise TypeError(_LazyString(_lazy_format, ("No conversion
>>> defined from %s to %s", R, self), {}))
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/structure/coerce_maps.pyx
>>> in sage.structure.coerce_maps.DefaultConvertMap_unique._call_with_args
>>> (build/cythonized/sage/structure/coerce_maps.c:5081)()
>>> 178 print(type(C), C)
>>> 179 print(type(C._element_constructor),
>>> C._element_constructor)
>>> --> 180 raise
>>> 181
>>> 182
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/structure/coerce_maps.pyx
>>> in sage.structure.coerce_maps.DefaultConvertMap_unique._call_with_args
>>> (build/cythonized/sage/structure/coerce_maps.c:4969)()
>>> 173 return C._element_constructor(x, *args)
>>> 174 else:
>>> --> 175 return C._element_constructor(x, *args, **kwds)
>>> 176 except Exception:
>>> 177 if print_warnings:
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/geometry/polyhedron/parent.py
>>> in _element_constructor_(self, *args, **kwds)
>>> 523 if convert and Vrep:
>>> 524 Vrep = [convert_base_ring(_) for _ in Vrep]
>>> --> 525 return self.element_class(self, Vrep, Hrep, **kwds)
>>> 526 if nargs == 1 and is_Polyhedron(args[0]):
>>> 527 polyhedron = args[0]
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/geometry/polyhedron/backend_cdd.py
>>> in __init__(self, parent, Vrep, Hrep, **kwds)
>>> 459 sage: TestSuite(p).run()
>>> 460 """
>>> --> 461 Polyhedron_cdd.__init__(self, parent, Vrep, Hrep, **kwds)
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/geometry/polyhedron/base.py
>>> in __init__(self, parent, Vrep, Hrep, **kwds)
>>> 125 elif Hrep is not None:
>>> 126 ieqs, eqns = Hrep
>>> --> 127 self._init_from_Hrepresentation(ieqs, eqns, **kwds)
>>> 128 else:
>>> 129 self._init_empty_polyhedron()
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/geometry/polyhedron/backend_cdd.py
>>> in _init_from_Hrepresentation(self, ieqs, eqns, verbose)
>>> 114 s = cdd_Hrepresentation(self._cdd_type, ieqs, eqns)
>>> 115 s = self._run_cdd(s, '--redcheck', verbose=verbose)
>>> --> 116 s = self._run_cdd(s, '--repall', verbose=verbose)
>>> 117 self._init_from_cdd_output(s)
>>> 118 if not self.base_ring().is_exact():
>>>
>>> /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/geometry/polyhedron/backend_cdd.py
>>> in _run_cdd(self, cdd_input_string, cmdline_arg, verbose)
>>> 163 if 'Error:' in ans + err:
>>> 164 # cdd reports errors on stdout and misc information on
>>> stderr
>>> --> 165 raise ValueError(ans.strip())
>>> 166 return ans
>>> 167
>>>
>>> ValueError: *Input Error: Input format is not correct.
>>> *Format:
>>> begin
>>> m n NumberType(real, rational or integer)
>>> b -A
>>> end
>>>
>>> How can i fix this problem!?
>>>
>>>
>>>
>>>
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