numpy-discussion

Re: [Numpy-discussion] tensor product

[Nadav H. <na...@vi...>]

There is a "tensortdot" function in numpy1.0rc1

  Nadav

-----Original Message-----
From:	num...@li... on behalf of =
Charles R Harris
Sent:	Sun 08-Oct-06 06:54
To:	num...@li...
Cc:=09
Subject:	[Numpy-discussion] tensor product

Hmmm,

I notice that there is no longer a tensor product. As it was the only =
one of
the outer, kron bunch that I really wanted, l miss it. In fact, I always
thought outer should act like the tensor product for the other binary
operators too. Anyway, mind if I put it back?

Chuck

Re: [Numpy-discussion] tensor product

[Charles R H. <cha...@gm...>]

Hi Nadav,

On 10/8/06, Nadav Horesh <na...@vi...> wrote:
>
>
> There is a "tensortdot" function in numpy1.0rc1



The tensordot is not the same thing as a tensor product. What I want is the
following:

def tensor(a, b) :
    """Tensor product of a and b

    """
    a = asarray(a)
    b = asarray(b)
    return outer(a, b).reshape(a.shape + b.shape)

Chuck

Re: [Numpy-discussion] tensor product

[Tim H. <tim...@ie...>]

Charles R Harris wrote:
> Hi Nadav,
>
> On 10/8/06, *Nadav Horesh* <na...@vi... 
> <mailto:na...@vi...>> wrote:
>
>
>     There is a "tensortdot" function in numpy1.0rc1
>
>
>
> The tensordot is not the same thing as a tensor product. What I want 
> is the following:
>
> def tensor(a, b) :
>     """Tensor product of a and b
>    
>     """
>     a = asarray(a)
>     b = asarray(b)
>     return outer(a, b).reshape(a.shape + b.shape)
>
Is this not the same things as numpy.multiply.outer(a, b)? (as opposed 
to outer(a, b), which appears to pretend that everything is a vector -- 
I'm not sure what the point of that is).

-tim

Re: [Numpy-discussion] tensor product

[Charles R H. <cha...@gm...>]

On 10/9/06, Tim Hochberg <tim...@ie...> wrote:
>
> <snip>

Is this not the same things as numpy.multiply.outer(a, b)? (as opposed
> to outer(a, b), which appears to pretend that everything is a vector --
> I'm not sure what the point of that is).


Hmmm, yes, multiply.outer does do that. I thought that outer was short for
multiply.outer and that the behaviour had changed. So the question is why
outer does what it does.

Chuck

Re: [Numpy-discussion] tensor product

[Travis O. <oli...@ie...>]

Charles R Harris wrote:
>
>
> On 10/9/06, *Tim Hochberg* <tim...@ie... 
> <mailto:tim...@ie...>> wrote:
>
>     <snip>
>
>     Is this not the same things as numpy.multiply.outer(a, b)? (as
>     opposed
>     to outer(a, b), which appears to pretend that everything is a
>     vector --
>     I'm not sure what the point of that is).
>
>
> Hmmm, yes, multiply.outer does do that. I thought that outer was short 
> for multiply.outer and that the behaviour had changed. So the question 
> is why outer does what it does.
Unfortunately,  I don't know the answer to that.

numpy.outer is the same as Numeric.outerproduct and does the same 
thing.  I'm not sure of the reason behind it.

-Travis

Re: [Numpy-discussion] tensor product

[Charles R H. <cha...@gm...>]

On 10/9/06, Travis Oliphant <oli...@ie...> wrote:
>
> Charles R Harris wrote:
> >
> >
> > On 10/9/06, *Tim Hochberg* <tim...@ie...
> > <mailto:tim...@ie...>> wrote:
> >
> >     <snip>
> >
> >     Is this not the same things as numpy.multiply.outer(a, b)? (as
> >     opposed
> >     to outer(a, b), which appears to pretend that everything is a
> >     vector --
> >     I'm not sure what the point of that is).
> >
> >
> > Hmmm, yes, multiply.outer does do that. I thought that outer was short
> > for multiply.outer and that the behaviour had changed. So the question
> > is why outer does what it does.
> Unfortunately,  I don't know the answer to that.
>
> numpy.outer is the same as Numeric.outerproduct and does the same
> thing.  I'm not sure of the reason behind it.


Looks sorta like a matrix thing. Maybe it should be called outerflat or some
such.

Chuck