Re: [Numpy-discussion] Dot product threading?

[<jor...@bo...>]

This thread discusses one of the things highest on my wishlist for=20
numpy. I have attached my first attempt at a code that will create a=20
broadcastingfunction that will broadcast a function over arrays where=20
the last N indices are assumed to be for use by the function, N=3D2 would=
=20
be used for matrices. It is implemented for Numeric.


/J=F6rgen


Pau Gargallo skrev:
>> Pau, can you confirm that this is the same
>> as the routine you're interested in?
>>
>> def dot2(a,b):
>>     '''Returns dot product of last two dimensions of two 3-D arrays,
>>     threaded over first dimension.'''
>>     try:
>>         assert a.shape[1] =3D=3D b.shape[2]
>>         assert a.shape[0] =3D=3D b.shape[0]
>>     except AssertionError:
>>         print "incorrect input shapes"
>>     res =3D zeros( (a.shape[0], a.shape[1], a.shape[1]), dtype=3Dfloat=
 )
>>     for i in range(a.shape[0]):
>>         res[i,...] =3D dot( a[i,...], b[i,...] )
>>     return res
>>
>=20
> yes, that is what I would like. I would like it even with more
> dimensions and with all the broadcasting rules ;-)
> These can probably be achieved by building actual 'arrays of matrices'
> (an array of matrix objects) and then using the ufunc machinery.
> But I think that a simple dot2 function (with an other name of course)
> will still very useful.
>=20
> pau
>=20
>=20
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>=20