[Numpy-discussion] in the NA discussion, what can we agree on?

[Pauli Virtanen]

04.11.2011 22:57, T J kirjoitti:
[clip]
> >   (m) mark-ignored
> >
> >   a := SPECIAL_1
> >   # -> a == SPECIAL_a ; the payload of the RHS is neglected,
> >   #                     the assigned value has the original LHS
> >   #                     as the payload
[clip]
> Does this behave as expected for "x + y" (as opposed to the inplace
> operation)?
[clip]

The definition is for assignment, and does not concern binary ops, so it 
behaves as expected. The inplace operation

 >>> x += y

is defined as equivalent to binary op followed by assignment

 >>> x[:] = x + y

as far as the missing values are concerned.

> However, doesn't this have the issue that Nathaniel brought up earlier:
> commutativity
>
> unignore(x + y) != unignore(y + x)

As the definition concerns only what happens on assignment, it does not 
have problems with commutativity.

-- 
Pauli Virtanen