add/subtract don't preserve col/row names

[dselivanov]

Hi! thx for you work. I found minor issue:

library(Matrix)
library(rfunctions)
xx = 1:10
m1 = sparseMatrix(i = xx, j = xx, x = xx, dims = c(10, 10), dimnames = list(xx, xx))
str(m1 + m1)

Formal class 'dgCMatrix' [package "Matrix"] with 6 slots
..@ i : int [1:10] 0 1 2 3 4 5 6 7 8 9
..@ p : int [1:11] 0 1 2 3 4 5 6 7 8 9 ...
..@ Dim : int [1:2] 10 10
..@ Dimnames:List of 2
.. ..$ : chr [1:10] "1" "2" "3" "4" ...
.. ..$ : chr [1:10] "1" "2" "3" "4" ...
..@ x : num [1:10] 2 4 6 8 10 12 14 16 18 20
..@ factors : list()

str(add(m1, m1))

Formal class 'dgCMatrix' [package "Matrix"] with 6 slots
..@ i : int [1:10] 0 1 2 3 4 5 6 7 8 9
..@ p : int [1:11] 0 1 2 3 4 5 6 7 8 9 ...
..@ Dim : int [1:2] 10 10
..@ Dimnames:List of 2
.. ..$ : NULL
.. ..$ : NULL
..@ x : num [1:10] 2 4 6 8 10 12 14 16 18 20
..@ factors : list()