‘SciViews::R’ - Fast and Parallelized R Functions

Philippe Grosjean (phgrosjean@sciviews.org)

2025-08-29

The {svFast} package provides a series of math and stat function that compute in parallel if the vector is large enough (by default >= 50,000 elements). Otherwise, these functions are simplified version of corresponding base R functions. They run on numeric vectors and do not retain any attributes of the input vector. They are not generic functions, on the contrary to their base R counterparts. They are designed to be fast when computing 100,000s to 100,000,000s items. Their names are the same as corresponding base functions followed by an underscore. For example, log_() is the fast version of log().

library(svFast)
# The number of threads used for calculation can be changed with:
#RcppParallel::setThreadOptions(numThreads = 4)

While vector x is short, the fun_() versions run sequentially at similar speed of base R equivalent for vectors roughly >= 1000 items. For smaller vectors, the overhead of Rcpp make these functions slower.

x <- 1:10
log_(x)
#>  [1] 0.0000000 0.6931472 1.0986123 1.3862944 1.6094379 1.7917595 1.9459101
#>  [8] 2.0794415 2.1972246 2.3025851
identical(log_(x), log(x))
#> [1] TRUE
# log in base 8
log_(x, base = 8)
#>  [1] 0.0000000 0.3333333 0.5283208 0.6666667 0.7739760 0.8616542 0.9357850
#>  [8] 1.0000000 1.0566417 1.1073094
bench::mark(log(x), log_(x)) # Slower with such a short vector
#> # A tibble: 2 × 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 log(x)        200ns 221.07ns  2297082.        0B        0
#> 2 log_(x)      1.55µs   1.84µs   529934.        0B        0

When x is long, the fun_() versions run in parallel and are much faster than the base R equivalent.

x2 <- runif(1e5)
# x2 size larger than 50,000, parallel computation activated
bench::mark(log(x2), log_(x2)) # Faster (depends on number of threads)
#> # A tibble: 2 × 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 log(x2)       841µs    899µs     1110.     781KB     17.8
#> 2 log_(x2)      455µs    476µs     2094.     781KB     31.8