Benchmarking optimisation of C++ code

[AlbanSagouis]

Here are benchmark results comparing C++ functions before and after the work in the branch albansagouis/cpp-optimisation and proposed in pull request #44 .

Essentially, changes focused on decreasing the use of Rcpp objects, passing objects by reference in C++ code and enforcing the use of const everywhere where needed.

In next steps with @mpadge, we will replace Rcpp by cpp11.

remotes::install_github(
  repo = "albansagouis/parzer@2f8ede4c909929aacc491c1d7e9d63e94c7e5312",
  force = TRUE)

microbenchmark::microbenchmark(
  times = 400L, setup = {x <- rep("45N54.2356", 10^4)},
  new = parzer:::pz_parse_lat(x),
  old = parzer:::pz_parse_lat_old(x)
)
# Unit: milliseconds
# expr      min       lq     mean   median       uq       max neval
# new 62.51737 62.88236 63.24100 63.11897 63.31802  66.57281   400
# old 67.82839 68.30346 69.14159 68.58070 69.06854 126.01239   400

microbenchmark::microbenchmark(
  times = 400L, setup = {x <- rep("45W54.2356", 10^4)},
  new = parzer:::pz_parse_lon(x),
  old = parzer:::pz_parse_lon_old(x)
)
# Unit: milliseconds
# expr      min       lq     mean   median       uq      max neval
# new 85.20321 85.60142 86.03875 85.79102 86.19459 91.38638   400
# old 90.85698 91.43344 92.06365 91.69679 92.14688 97.74293   400



microbenchmark::microbenchmark(
  times = 10^6, setup = {x <- 45.235687},
  new = parzer:::split_decimal_degree(x),
  old = parzer:::split_decimal_degree_old(x)
)
# Unit: microseconds
# expr   min    lq     mean median    uq      max neval
# new 4.920 5.207 5.949933  5.371 5.535 62011.52 1e+06
# old 5.494 5.822 6.519910  5.986 6.150 12322.26 1e+06

Session Info

> devtools::session_info("loaded")
─ Session info ─────────────────────────────────────────────────────────────────
 setting  value
 version  R version 4.2.1 (2022-06-23)
 os       macOS Ventura 13.0.1
 system   aarch64, darwin20
 ui       RStudio
 language (EN)
 collate  en_US.UTF-8
 ctype    en_US.UTF-8
 tz       Europe/Berlin
 date     2022-12-09
 rstudio  2022.07.2+576 Spotted Wakerobin (desktop)
 pandoc   NA