Standard deviation of columns and rows in sparse matrix

Description

Produces the same result as apply(x, 1, sd) or apply(x, 2, sd) without coercing matrix to dense matrix. Values are not identical to sd because of the floating point precision issue in C++.

Usage

colSds(x)

rowSds(x)

Arguments

Examples

mt <- Matrix::rsparsematrix(100, 100, 0.01)
colSds(mt)
apply(mt, 2, sd) # the same