message: Comments for the functors in concat_lib
diff: @@ -23,6 +23,22 @@ limitations under the License.
  namespace tensorflow {
  +// Functors to concatenate tensors. These always take a rank-2 tensor (i.e a
  +// matrix) and concatenate it along the axis 1 ("putting them next to each
  +// other" as opposed to "putting them on top of one another").
  +//
  +// Any concatenation of n-dimensional tensors across any axis can be reduced to
  +// a concatenation of two-dimensional tensors across the axis 1 by first
  +// partitioning the axes of the original tensors into those less than the axis
  +// to be concatenated across and the rest. Then reshape the tensors into a
  +// two-dimensional tensor by collapsing these two sets of axes and concatenate
  +// the resulting matrices across the axis 1, finally reshaping the result to
  +// have the proper shape.
  +//
  +// So, for example, when stacking N tensors, reshape each to have shape
  +// {1, Numelements} and reshape the result matrix to have shape
  +// {1, N * NumElements} before passing it to this functor.
  +
  // Assumes all inputs are nonempty
  template <typename T>
  void ConcatCPU(DeviceBase* d,
  