grbase-utilities function

gRbase utilities

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

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

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)
## Not run:

system.time(for (ii in 1:100000)  t(v * t(X)))
system.time(for (ii in 1:100000)  colwiseProd(v, X))
## End(Not run)


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]))
}

Author(s)

Søren Højsgaard, sorenh@math.aau.dk