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])

Author

Søren Højsgaard, sorenh@math.aau.dk

Examples

## colwiseProd
X <- matrix(1:16, nrow=4)
v <- 1:4
t(v * t(X))
#>      [,1] [,2] [,3] [,4]
#> [1,]    1   10   27   52
#> [2,]    2   12   30   56
#> [3,]    3   14   33   60
#> [4,]    4   16   36   64
colwiseProd(v, X)
#>      [,1] [,2] [,3] [,4]
#> [1,]    1   10   27   52
#> [2,]    2   12   30   56
#> [3,]    3   14   33   60
#> [4,]    4   16   36   64
if (FALSE) { # \dontrun{
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)
#> [[1]]
#> [1] NA  1  2
#> 
#> [[2]]
#> [1]  1  2 NA
#> 
#> [[3]]
#> [1]  1 NA NA
#> 
lapply(setlist, function(gg) match(gg, item))
#> [[1]]
#> [1] NA  1  2
#> 
#> [[2]]
#> [1]  1  2 NA
#> 
#> [[3]]
#> [1]  1 NA NA
#> 

lapplyI2V(setlist, item)
#> [[1]]
#> [1]  2  3 NA
#> 
#> [[2]]
#> [1]  3 NA NA
#> 
#> [[3]]
#> [1]  3 NA NA
#> 
lapply(setlist, function(x) item[x])
#> [[1]]
#> [1]  2  3 NA
#> 
#> [[2]]
#> [1]  3 NA NA
#> 
#> [[3]]
#> [1]  3 NA NA
#> 

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]))
}
#> Unit: microseconds
#>                                      expr   min     lq    mean median     uq
#>                  lapplyI2V(setlist, item) 1.707 1.7825 1.93210 1.8790 1.9515
#>  lapply(setlist, function(elt) item[elt]) 1.573 1.6420 1.86108 1.7295 1.8430
#>     max neval cld
#>   5.872   100   a
#>  11.289   100   a