+1 (binding)
Just one comment, though: since we also define a separate "Tensor" IPC
structure in Arrow, maybe we should state the relationship somewhere in the
documentation? (Even if the answer is "no relationship".)
On Mon, Mar 6, 2023, at 18:58, Rok Mihevc wrote:
> +1
>
> Thanks for the discussion everyone!
>
> Rok
>
> On Mon, Mar 6, 2023 at 8:29 PM Dewey Dunnington
> <de...@voltrondata.com.invalid> wrote:
>
>> +1 (non-binding)!
>>
>> On Mon, Mar 6, 2023 at 9:59 AM Nic Crane <thisis...@gmail.com> wrote:
>>
>> > +1
>> >
>> > On Mon, 6 Mar 2023 at 12:41, Alenka Frim <ale...@voltrondata.com
>> .invalid>
>> > wrote:
>> >
>> > > Hi all,
>> > >
>> > > I am starting a new voting thread with this email as the first voting
>> > > thread [1] opened up new
>> > > comments and suggestions and we wanted to take time to see how that
>> > > evolves.
>> > >
>> > > *I would like to propose we vote on adding the fixed shape tensor
>> > canonical
>> > > extension type*
>> > > *with the following specification:*
>> > >
>> > > Fixed shape tensor
>> > > ==================
>> > >
>> > > * Extension name: `arrow.fixed_shape_tensor`.
>> > >
>> > > * The storage type of the extension: ``FixedSizeList`` where:
>> > >
>> > > * **value_type** is the data type of individual tensor elements.
>> > > * **list_size** is the product of all the elements in tensor shape.
>> > >
>> > > * Extension type parameters:
>> > >
>> > > * **value_type** = the Arrow data type of individual tensor elements.
>> > > * **shape** = the physical shape of the contained tensors
>> > > as an array.
>> > >
>> > > Optional parameters describing the logical layout:
>> > >
>> > > * **dim_names** = explicit names to tensor dimensions
>> > > as an array. The length of it should be equal to the shape
>> > > length and equal to the number of dimensions.
>> > >
>> > > ``dim_names`` can be used if the dimensions have well-known
>> > > names and they map to the physical layout (row-major).
>> > >
>> > > * **permutation** = indices of the desired ordering of the
>> > > original dimensions, defined as an array.
>> > >
>> > > The indices contain a permutation of the values [0, 1, .., N-1]
>> where
>> > > N is the number of dimensions. The permutation indicates which
>> > > dimension of the logical layout corresponds to which dimension of
>> the
>> > > physical tensor (the i-th dimension of the logical view corresponds
>> > > to the dimension with number ``permutations[i]`` of the physical
>> > > tensor).
>> > >
>> > > Permutation can be useful in case the logical order of
>> > > the tensor is a permutation of the physical order (row-major).
>> > >
>> > > When logical and physical layout are equal, the permutation will
>> > always
>> > > be ([0, 1, .., N-1]) and can therefore be left out.
>> > >
>> > > * Description of the serialization:
>> > >
>> > > The metadata must be a valid JSON object including shape of
>> > > the contained tensors as an array with key **"shape"** plus optional
>> > > dimension names with keys **"dim_names"** and ordering of the
>> > > dimensions with key **"permutation"**.
>> > >
>> > > - Example: ``{ "shape": [2, 5]}``
>> > > - Example with ``dim_names`` metadata for NCHW ordered data:
>> > >
>> > > ``{ "shape": [100, 200, 500], "dim_names": ["C", "H", "W"]}``
>> > >
>> > > - Example of permuted 3-dimensional tensor:
>> > >
>> > > ``{ "shape": [100, 200, 500], "permutation": [2, 0, 1]}``
>> > >
>> > > This is the physical layout shape and the the shape of the logical
>> > > layout would in this case be ``[500, 100, 200]``.
>> > >
>> > > .. note::
>> > >
>> > > Elements in a fixed shape tensor extension array are stored
>> > > in row-major/C-contiguous order.
>> > >
>> > > * The specification is submitted as a PR [2] to Canonical Extension
>> Types
>> > > document under the
>> > > format specifications directory [3].
>> > >
>> > > There are also two implementations submitted to Apache Arrow
>> repository:
>> > > * C++ implementation of the proposed specification [4]
>> > > * Python example implementation of the proposed specification and usage
>> > > (only illustrative) [5]
>> > >
>> > >
>> > > The vote will be open for at least 72 hours.
>> > >
>> > > [ ] +1 Accept this proposal
>> > > [ ] +0
>> > > [ ] -1 Do not accept this proposal because...
>> > >
>> > >
>> > > Regards, Alenka
>> > >
>> > > [1]: https://lists.apache.org/thread/3cj0cr44hg3t2rn0kxly8td82yfob1nd
>> > > [2]: https://github.com/apache/arrow/pull/33925/files
>> > > [3]:
>> > >
>> > >
>> >
>> https://github.com/apache/arrow/blob/main/docs/source/format/CanonicalExtensions.rst
>> > >
>> > > [4]: https://github.com/apache/arrow/pull/8510/files
>> > > [5]: https://github.com/apache/arrow/pull/33948/files
>> > >
>> >
>>
