sparsity: Sparsity of Matrix Objects
In RBigData/pbdDMAT: 'pbdR' Distributed Matrix Methods

Determine the sparsity of a matrix, distributed, dense, or otherwise.

## S4 method for signature 'matrix'
sparsity(x, count = "zero", out = "count", tol = .Machine$double.eps)

## S4 method for signature 'vector'
sparsity(x, count = "zero", out = "count", tol = .Machine$double.eps)

## S4 method for signature 'dmat'
sparsity(x, count = "zero", out = "count", tol = .Machine$double.eps)

`x`	numeric matrix
`count`	character; options are "zero" and "other". The former counts the number of zeros, while the latter counts the number of non-zeros ('other' elements).
`out`	character; options are "count", "proportion", and "percent". This determines whether a pure count, proportion of `count` elements in the matrix, or percentage of `count` elements in the matrix.
`tol`	numeric; the tolerance for numerical zero. This is ignored if the input data is integer/logical.