colSums {Matrix} R Documentation

Form Row and Column Sums and Means

Description

Form row and column sums and means for `Matrix` objects.

Usage

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

## S4 method for signature 'CsparseMatrix'
colSums(x, na.rm = FALSE,
dims = 1, sparseResult = FALSE)
## S4 method for signature 'CsparseMatrix'
rowSums(x, na.rm = FALSE,
dims = 1, sparseResult = FALSE)
## S4 method for signature 'CsparseMatrix'
colMeans(x, na.rm = FALSE,
dims = 1, sparseResult = FALSE)
## S4 method for signature 'CsparseMatrix'
rowMeans(x, na.rm = FALSE,
dims = 1, sparseResult = FALSE)
```

Arguments

 `x` a Matrix, i.e., inheriting from `Matrix`. `na.rm` logical. Should missing values (including `NaN`) be omitted from the calculations? `dims` completely ignored by the `Matrix` methods. `...` potentially further arguments, for method `<->` generic compatibility. `sparseResult` logical indicating if the result should be sparse, i.e., inheriting from class `sparseVector`.

Value

returns a numeric vector if `sparseResult` is `FALSE` as per default. Otherwise, returns a `sparseVector`.

`colSums` and the `sparseVector` classes.

Examples

```(M <- bdiag(Diagonal(2), matrix(1:3, 3,4), diag(3:2))) # 7 x 8
colSums(M)
d <- Diagonal(10, c(0,0,10,0,2,rep(0,5)))
MM <- kronecker(d, M)
dim(MM) # 70 80
length(MM@x) # 160, but many are '0' ; drop those:
MM <- drop0(MM)
length(MM@x) # 32
cm <- colSums(MM)
(scm <- colSums(MM, sparseResult = TRUE))
stopifnot(is(scm, "sparseVector"),
identical(cm, as.numeric(scm)))
rowSums(MM, sparseResult = TRUE) # 16 of 70 are not zero
colMeans(MM, sparseResult = TRUE)
## Since we have no 'NA's, these two are equivalent :
stopifnot(identical(rowMeans(MM, sparseResult = TRUE),
rowMeans(MM, sparseResult = TRUE, na.rm = TRUE)),
rowMeans(Diagonal(16)) == 1/16,
colSums(Diagonal(7)) == 1)
```

[Package Matrix version 1.0-11 Index]