Form row and column sums and means for sparse `spam`

matrices

```
rowSums(x, na.rm = FALSE, dims = 1, ...)
colSums(x, na.rm = FALSE, dims = 1, ...)
rowMeans(x, na.rm = FALSE, dims = 1, ...)
colMeans(x, na.rm = FALSE, dims = 1, ...)
```

## Arguments

- x
a `spam`

object

- na.rm
currently ignored

- dims
ignored as we have only two dimensions.

- ...
potentially further arguments from other methods.

## Details

Depending on the flag

.

## Value

Vector of appropriate length.

## Examples

```
x <- spam( rnorm(20), 5, 4)
rowSums( x)
#> [1] -1.2731599 0.2250209 -2.5242495 2.8047041 -1.7852808
c( x %*% rep(1,4))
#> [1] -1.2731599 0.2250209 -2.5242495 2.8047041 -1.7852808
```