Rollup Sparse Arrays
Rollup (aggregate) sparse arrays along arbitrary dimensions.
rollup(x, MARGIN, INDEX, FUN, ...)
## S3 method for class 'simple_triplet_matrix'
rollup(x, MARGIN, INDEX = NULL, FUN = sum, ...,
REDUCE = FALSE)
## S3 method for class 'simple_sparse_array'
rollup(x, MARGIN, INDEX = NULL, FUN = sum, ...,
DROP = FALSE, EXPAND = c("none", "sparse", "dense", "all"),
MODE = "double")
## S3 method for class 'matrix'
rollup(x, MARGIN, INDEX = NULL, FUN = sum, ...,
DROP = FALSE, MODE = "double")
## S3 method for class 'array'
rollup(x, MARGIN, INDEX = NULL, FUN = sum, ...,
DROP = FALSE, MODE = "double")x |
a sparse (or dense) array, typically of numeric or logical values. |
MARGIN |
a vector giving the subscripts (names) of the dimensions to be rolled up. |
INDEX |
a corresponding ( |
FUN |
the name of the function to be applied. |
REDUCE |
option to remove zeros from the result. |
DROP |
option to delete the dimensions of the result which have only one level. |
EXPAND |
the cell expansion method to use (see Details). |
MODE |
the type to use for the values if the result is empty. |
... |
optional arguments to |
Provides aggregation of sparse and dense arrays, in particular fast summation over the rows or columns of sparse matrices in
simple_triplet-form.
If (a component of) INDEX contains NA values the
corresponding parts of x are omitted.
For simple_sparse_array the following cell expansion methods are
provided:
none:The non-zero entries of a cell, if any, are
supplied to FUN as a vector.
sparse:The number of zero entries of a cell is supplied in addition to above, as a second argument.
dense:Cells with non-zero entries are expanded to
a dense array and supplied to FUN.
all:All cells are expanded to a dense array
and supplied to FUN.
Note that the memory and time consumption increases with the level of expansion.
Note that the default method tries to coerce x to array.
An object of the same class as x where for class
simple_triplet_matrix the values are always of type double
if FUN = sum (default).
The dimnames corresponding to MARGIN are based on (the
components of) INDEX.
Currently most of the code is written in R and, therefore, the memory and time it consumes is not optimal.
Christian Buchta
simple_triplet_matrix and simple_sparse_array
for sparse arrays.
apply for dense arrays.
##
x <- matrix(c(1, 0, 0, 2, 1, NA), nrow = 2,
dimnames = list(A = 1:2, B = 1:3))
x
apply(x, 1L, sum, na.rm = TRUE)
##
rollup(x, 2L, na.rm = TRUE)
##
rollup(x, 2L, c(1,2,1), na.rm = TRUE)
## omit
rollup(x, 2L, c(1,NA,1), na.rm = TRUE)
## expand
a <- as.simple_sparse_array(x)
a
r <- rollup(a, 1L, FUN = mean, na.rm = TRUE, EXPAND = "dense")
as.array(r)
##
r <- rollup(a, 1L, FUN = function(x, nz)
length(x) / (length(x) + nz),
EXPAND = "sparse"
)
as.array(r)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.