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@njtierney
Created June 5, 2025 03:24
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crossprod vs t() %*%
pi_mat <- matrix(c(0.5, 0.5))
z_mat <- matrix(c(32, 1))  

bm <- bench::mark(
  t = t(pi_mat) %*% z_mat,
  crossprod = crossprod(pi_mat, z_mat)
)

bm
#> # A tibble: 2 × 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 t             656ns    738ns  1147673.        0B     115.
#> 2 crossprod       1ns     82ns 14145153.        0B       0
summary(bm, relative = TRUE)
#> # A tibble: 2 × 6
#>   expression   min median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <dbl>  <dbl>     <dbl>     <dbl>    <dbl>
#> 1 t           656.   9.00       1         NaN      Inf
#> 2 crossprod     1    1         12.3       NaN      NaN

plot(bm)

Created on 2025-06-05 with reprex v2.1.1

Session info

sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#>  setting  value
#>  version  R version 4.5.0 (2025-04-11)
#>  os       macOS Sonoma 14.5
#>  system   aarch64, darwin20
#>  ui       X11
#>  language (EN)
#>  collate  en_US.UTF-8
#>  ctype    en_US.UTF-8
#>  tz       Australia/Hobart
#>  date     2025-06-05
#>  pandoc   3.4 @ /Applications/RStudio.app/Contents/Resources/app/quarto/bin/tools/aarch64/ (via rmarkdown)
#>  quarto   1.7.31 @ /usr/local/bin/quarto
#> 
#> ─ Packages ───────────────────────────────────────────────────────────────────
#>  package      * version    date (UTC) lib source
#>  beeswarm       0.4.0      2021-06-01 [1] CRAN (R 4.5.0)
#>  bench          1.1.4      2025-01-16 [1] CRAN (R 4.5.0)
#>  cli            3.6.5      2025-04-23 [1] CRAN (R 4.5.0)
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#>  digest         0.6.37     2024-08-19 [1] CRAN (R 4.5.0)
#>  dplyr          1.1.4      2023-11-17 [1] CRAN (R 4.5.0)
#>  evaluate       1.0.3      2025-01-10 [1] CRAN (R 4.5.0)
#>  farver         2.1.2      2024-05-13 [1] CRAN (R 4.5.0)
#>  fastmap        1.2.0      2024-05-15 [1] CRAN (R 4.5.0)
#>  fs             1.6.6      2025-04-12 [1] CRAN (R 4.5.0)
#>  generics       0.1.4      2025-05-09 [1] CRAN (R 4.5.0)
#>  ggbeeswarm     0.7.2      2023-04-29 [1] CRAN (R 4.5.0)
#>  ggplot2        3.5.2      2025-04-09 [1] CRAN (R 4.5.0)
#>  glue           1.8.0      2024-09-30 [1] CRAN (R 4.5.0)
#>  gtable         0.3.6      2024-10-25 [1] CRAN (R 4.5.0)
#>  htmltools      0.5.8.1    2024-04-04 [1] CRAN (R 4.5.0)
#>  knitr          1.50       2025-03-16 [1] CRAN (R 4.5.0)
#>  lifecycle      1.0.4      2023-11-07 [1] CRAN (R 4.5.0)
#>  magrittr       2.0.3      2022-03-30 [1] CRAN (R 4.5.0)
#>  pillar         1.10.2     2025-04-05 [1] CRAN (R 4.5.0)
#>  pkgconfig      2.0.3      2019-09-22 [1] CRAN (R 4.5.0)
#>  profmem        0.6.0      2020-12-13 [1] CRAN (R 4.5.0)
#>  purrr          1.0.4.9000 2025-05-04 [1] Github (tidyverse/purrr@9c8beb4)
#>  R6             2.6.1      2025-02-15 [1] CRAN (R 4.5.0)
#>  RColorBrewer   1.1-3      2022-04-03 [1] CRAN (R 4.5.0)
#>  reprex         2.1.1      2024-07-06 [1] CRAN (R 4.5.0)
#>  rlang          1.1.6      2025-04-11 [1] CRAN (R 4.5.0)
#>  rmarkdown      2.29       2024-11-04 [1] CRAN (R 4.5.0)
#>  rstudioapi     0.17.1     2024-10-22 [1] CRAN (R 4.5.0)
#>  scales         1.4.0      2025-04-24 [1] CRAN (R 4.5.0)
#>  sessioninfo    1.2.3      2025-02-05 [1] CRAN (R 4.5.0)
#>  tibble         3.2.1      2023-03-20 [1] CRAN (R 4.5.0)
#>  tidyr          1.3.1      2024-01-24 [1] CRAN (R 4.5.0)
#>  tidyselect     1.2.1      2024-03-11 [1] CRAN (R 4.5.0)
#>  utf8           1.2.5      2025-05-01 [1] CRAN (R 4.5.0)
#>  vctrs          0.6.5      2023-12-01 [1] CRAN (R 4.5.0)
#>  vipor          0.4.7      2023-12-18 [1] CRAN (R 4.5.0)
#>  withr          3.0.2      2024-10-28 [1] CRAN (R 4.5.0)
#>  xfun           0.52       2025-04-02 [1] CRAN (R 4.5.0)
#>  xml2           1.3.8      2025-03-14 [1] CRAN (R 4.5.0)
#>  yaml           2.3.10     2024-07-26 [1] CRAN (R 4.5.0)
#> 
#>  [1] /Users/nick_1/Library/R/arm64/4.5/library
#>  [2] /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/library
#> 
#> ──────────────────────────────────────────────────────────────────────────────
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