[SciPy-dev] Suppressing of numpy __mul__, __div__ etc
Dmitrey
tmp50@ukr....
Thu Dec 17 07:28:02 CST 2009
От кого: Sebastian Walter <sebastian.walter@gmail.com>
1) From an abstract point of view, oofun should be a data type.
And the container of choice would be a numpy.array of dtype ofun, not
of dtype object.
so array([1,2,3],dtype=float) * oofun(2) should return
array([2,4,6],dtype=returntype(oofun,float))
What do you mean under oofun(2) ?!
oofun is
array([1,2,3],dtype=float) * oofun_instance should return result of type oofun and nothing else.
Same to other classes - SAGE, polinomials, etc.
When ndarray.__mul__(self, other) is called, and other is a container,
it should simply check if it knows how to handle that container.
If ndarray doesn't know, it should call the other.__rmul__ and hope
that `other` knows what to do.
E.g.
class matrix:
iscontainer = True
....
class ndarray:
def __mul__(self, other):
if other.iscontainer:
if not know_what_to_do_with(other):
other.__rmul__(self)
else:
do what is done now: treat other as dtype=object
then array * matrix
would call the ndarray.__mul__ operator
it then realizes that matrix is a container but ndarray doesnt know
what to do with it. It would therefore call matrix.__rmul__
If other is not a container it is treated as object and we would get
the current behaviour. This would allow to stay backward compatible.
As for me, I dislike the idea - it's too complicated, and some containers sometimes could want to take operations priority, using their __rmul__ etc instead of ndarray __mul__ etc.
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