#14214: Cythoned homsets
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Reporter: SimonKing | Owner: tbd
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-5.10
Component: performance | Resolution:
Keywords: Hom, cython, cached method | Work issues: How to store
domain and codomain?
Report Upstream: N/A | Reviewers:
Authors: Simon King | Merged in:
Dependencies: #14159, #12951, #13184 | Stopgaps:
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Changes (by SimonKing):
* work_issues: Use property for domain and codomain => How to store
domain and codomain?
Comment:
This is why I am not happy with "property":
{{{
sage: cython("""
from sage.structure.parent cimport Parent
cdef class Bla(Parent):
property _domain:
def __get__(self):
try:
return self.__cached_methods['_domain']
except KeyError:
raise AttributeError("%s instance has no attribute
'_domain'"%type(self))
except TypeError:
self.__cached_methods = {}
raise AttributeError("%s instance has no attribute
'_domain'"%type(self))
def __set__(self, value):
try:
self.__cached_methods['_domain'] = value
except TypeError:
self.__cached_methods = {}
self.__cached_methods['_domain'] = value
""")
....:
sage: class Blubb(Bla): pass
sage: b = Bla()
sage: c = Blubb()
sage: b._domain = 1
sage: c._domain = 1
sage: c._codomain = 2
sage: %timeit x = b._domain
10000000 loops, best of 3: 133 ns per loop
sage: %timeit x = c._domain
10000000 loops, best of 3: 144 ns per loop
sage: %timeit x = c._codomain
10000000 loops, best of 3: 110 ns per loop
}}}
So, the property becomes slower on the subclass than on the base class,
and a usual attribute on the subclass is faster than the property on the
base class.
I don't know if a solution to this problem is proposed in your comments
(perhaps "cythoning lazy attributes"?).
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14214#comment:33>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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