On Feb 3, 1:37 am, Nils Bruin <nbr...@sfu.ca> wrote:
> See line 1807 for sage/misc/cachefunc.pyx:
Actually, I'm not so sure that code ever gets executed in our example.
I certainly didn't get any results from putting "raise" or "print"
commands there. On class level, there's the CachedMethod that is
supposed to instantiate CachedMethodCaller to package bound methods.
Line 2047 of the CachedMethod.__get__:
try:
name = self._cachedfunc.__name__
except AttributeError:
name = self.__name__
[Caller = <some CachedMethodCaller or CachedMethodCallerNoArgs
instance>]
try:
setattr(inst,name, Caller)
return Caller
<attempt to store Caller under inst.__cached_methods>
return Caller
so things actually go haywire earlier -- and they do for the with
arguments version as well. If Foo.trac=Foo.truc is executed, it
actually ISN'T a copy of the CachedMethod instance that is bound to
Foo.truc. It's an unbound CachedMethodCaller (with inst=None). So it
seems to me first of all
class Foo:
...
trac = truc
and
class Foo:
...
Foo.trac = Foo.truc
are actually NOT the same. Furthermore, in both cases, while things
seem to work for methods that do take arguments, the alias is actually
quite a bit slower. This is due to the fact that new instances of
CachedMethodCaller keep being created and rebound, even though the
lookup in the cache succeeds in that case:
sage: %timeit c.truc(1)
625 loops, best of 3: 1.08 µs per loop
sage: %timeit c.trac(1)
625 loops, best of 3: 2.58 µs per loop
sage: Foo.tric = Foo.truc
sage: %timeit c.tric(1) #varies quite a bit
625 loops, best of 3: 1.69 µs per loop
so in all cases, aliasing does NOT work well with cached_method.
Furthermore, I think the logic behind some of the __get__ methods
might need some reconsideration. It seems that the
MethodCaller.__get__ tries to replicate some of the functionality of
CachedMethod.__get__ (which is really required to "bind" the cached
method), but I'm not sure it should.
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