gRbase (version 2.0.3)

grbase-utilities: gRbase utilities

Description

Various utility functions for gRbase. Includes 'faster versions' of certain standard R functions.

Usage

rhsFormula2list(form)
rhsf2list(form)
rhsf2vec(form)
listify_dots(dots)
list2rhsFormula(form)
list2rhsf(form)
rowmat2list(X)
colmat2list(X)
matrix2list(X, byrow = TRUE)
which.arr.index(X)
which_matrix_index(X)
rowSumsPrim(X)
colSumsPrim(X)
colwiseProd(v, X)
lapplyV2I(setlist, item)
lapplyI2V(setlist, item)

Arguments

form

Formula specification (a right-hand sided formula, a numeric/character vector or a list of vectors).

dots

dot-arguments to be turned into a list

X

A matrix.

byrow

Should the split be by row or by column.

v

A vector.

setlist

A list of atomic vectors

item

An atomic vector

Author

Søren Højsgaard,

Details

which.arr.ind: Returns matrix n x 2 matrix with indices of non-zero entries in matrix X. Notice which_matrix_index__ is cpp implementation.

colwiseProd: multiplies a vector v and a matrix X columnwise (as opposed to rowwise which is achieved by v * X). Hence colwiseProd does the same as t(v * t(X)) - but it does so faster for numeric values.

• lapplyV2I: same as but much faster than lapply(setlist, function(elt) match(elt, item))

• lapplyI2V: same as but faster than lapply(setlist, function(elt) item[elt])

Examples

## colwiseProd
X <- matrix(1:16, nrow=4)
v <- 1:4
t(v * t(X))
colwiseProd(v, X)
if (FALSE) {
system.time(for (ii in 1:100000)  t(v * t(X)))
system.time(for (ii in 1:100000)  colwiseProd(v, X))
}


setlist <- list(c(1,2,3), c(2,3,4), c(2,4,5))
item <- c(2,3)

lapplyV2I(setlist, item)
lapply(setlist, function(gg) match(gg, item))

lapplyI2V(setlist, item)
lapply(setlist, function(x) item[x])

if (require(microbenchmark)){
microbenchmark(
  lapplyV2I(setlist, item),
  lapply(setlist, function(elt) match(elt, item)))

microbenchmark::microbenchmark(
  lapplyI2V(setlist, item),
  lapply(setlist, function(elt) item[elt]))
}