Distributed matrices with column counts represented by Int (rather than Long)

[Phillip Henry]

Hi,

I notice that some DistributedMatrix represent the number of columns with
an Int rather than a Long (RowMatrix etc). This limits the number of
columns to about 2 billion.

We're approaching that limit. What do people recommend we do to mitigate
the problem? Are there plans to use a larger data type as the trait
suggests it should be?

Regards,

Phillip