Re: [eigen] Merge Tensor module

A quick +1 to say I have been looking forward to seeing this in /unsupported so I can try it. Thanks to Benoit for working on it.

Toby

From: Gael Guennebaud <gael.guennebaud@xxxxxxxxx>
Sent: 09 February 2015 08:43
To: eigen
Subject: [eigen] Merge Tensor module

Hi,

I'm willing to merge Benoit Steiner's Tensor module in unsupported/. See pull-request #96 (https://bitbucket.org/eigen/eigen/pull-request/96).

Feel free to object with arguments.

Basically, it supports the following features:

- arbitrary tensor rank (up to 5 in C++03)

- fully-dynamic or fully-fixed dimensions

- forward or backward storage order (like row-major/column-major)

- slicing, chipping (pick a R-1 rank sub tensor), reduction,

- contractions using Eigen's fast matrix-matrix and matrix-vector kernels,

- reshape, shuffling of the dimensions,

- convolutions

- etc.

There are also a few features aiming to be integrated in Eigen core. In particular, the evaluation of expressions on CUDA and a fast CUDA matrix-matrix kernel.

Before it can be integrated within Eigen's official modules, we will have to unify everything that can be unified:

- the evaluator mechanisms (more on that later)

- unify Tensor and FixedSizeTensor while enabling mixed fixed-dynamic sizes

- TensorMap -> Map<Tensor>

- CUDA stuffs (more on that later)

- move the documentation to Doxygen

- clean Eigen::array, Eigen::DSizes if possible

- fix Eigen::IndexList (it currently requires C++14)

- etc.

and also stabilize the naming convensions (more on that later).

Additional welcome features could be:

- Ref<Tensor>

- Iterator based evaluation for large-rank _expression_ with complex indexing

- cost model (could allow to switch between index-based and iterator-based evaluation

- unify 1D/2D tensors with MatrixBase?

Nonetheless, I think this is a good timing for the merge as the current implementation is already pretty mature and this will provide the visibility this module deserves.

Cheers,

Gael.