Collapse high-dimensional tensor array

Collapse high-dimensional tensor array

Usage

collapse2(x, keep, method = c("mean", "sum"), ...)

# S3 method for class 'FileArray'
collapse2(x, keep, method = c("mean", "sum"), ...)

# S3 method for class 'Tensor'
collapse2(x, keep, method = c("mean", "sum"), ...)

# S3 method for class 'array'
collapse2(x, keep, method = c("mean", "sum"), ...)

Arguments

x

R array, FileArray-class, or Tensor object

keep

integer vector, the margins to keep

method

character, calculates mean or sum of the array when collapsing

...

passed to other methods

Value

A collapsed array (or a vector or matrix), depending on keep

See also

collapse

Examples

x <- array(1:16, rep(2, 4))

collapse2(x, c(3, 2))
#>      [,1] [,2]
#> [1,]  5.5  7.5
#> [2,]  9.5 11.5

# Alternative method, but slower when `x` is a large array
apply(x, c(3, 2), mean)
#>      [,1] [,2]
#> [1,]  5.5  7.5
#> [2,]  9.5 11.5

# filearray
y <- filearray::as_filearray(x)

collapse2(y, c(3, 2))
#>      [,1] [,2]
#> [1,]  5.5  7.5
#> [2,]  9.5 11.5

collapse2(y, c(3, 2), "sum")
#>      [,1] [,2]
#> [1,]   22   30
#> [2,]   38   46

# clean up
y$delete(force = TRUE)