R Under development (unstable) (2023-12-09 r85665 ucrt) -- "Unsuffered Consequences"
Copyright (C) 2023 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library("matrixStats")
> library("utils")  ## utils::str
> 
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> # Local functions
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> psortKM_R <- function(x, k, m) {
+   x <- sort(x)
+   x[(k - m + 1):k]
+ }
> 
> psortKM_R2 <- function(x, k, m) {
+   partial <- (k - m + 1):k
+   x <- sort.int(x, partial = partial)
+   x[partial]
+ }
> 
> 
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> # Consistency checks
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> set.seed(1)
> 
> cat("Consistency checks:\n")
Consistency checks:
> x <- 1:30
> x[18:20] <- 20
> y <- sample(x)
> cat("x:\n")
x:
> str(x)
 num [1:30] 1 2 3 4 5 6 7 8 9 10 ...
> cat("sample(x):\n")
sample(x):
> str(y)
 num [1:30] 25 4 7 1 2 23 11 14 20 20 ...
> 
> for (k in c(1L, 2L, 20L, 21L, length(x))) {
+   for (m in 1:min(5L, k)) {
+     px0 <- psortKM_R(x, k = k, m = m)
+     px0b <- psortKM_R2(x, k = k, m = m)
+     stopifnot(identical(px0b, px0))
+     px1 <- matrixStats:::.psortKM(x, k = k, m = m)
+     cat(sprintf(".psortKM(x, k = %d, m = %d):\n", k, m))
+     print(px1)
+     stopifnot(identical(px1, px0))
+ 
+     py0 <- psortKM_R(y, k = k, m = m)
+     py0b <- psortKM_R2(y, k = k, m = m)
+     stopifnot(identical(py0b, py0))
+     py1 <- matrixStats:::.psortKM(y, k = k, m = m)
+     cat(sprintf(".psortKM(y, k = %d, m = %d):\n", k, m))
+     print(py1)
+     stopifnot(identical(py1, py0))
+     stopifnot(identical(py1, px1))
+   } # for (m ...)
+ } # for (k ...)
.psortKM(x, k = 1, m = 1):
[1] 1
.psortKM(y, k = 1, m = 1):
[1] 1
.psortKM(x, k = 2, m = 1):
[1] 2
.psortKM(y, k = 2, m = 1):
[1] 2
.psortKM(x, k = 2, m = 2):
[1] 1 2
.psortKM(y, k = 2, m = 2):
[1] 1 2
.psortKM(x, k = 20, m = 1):
[1] 20
.psortKM(y, k = 20, m = 1):
[1] 20
.psortKM(x, k = 20, m = 2):
[1] 20 20
.psortKM(y, k = 20, m = 2):
[1] 20 20
.psortKM(x, k = 20, m = 3):
[1] 20 20 20
.psortKM(y, k = 20, m = 3):
[1] 20 20 20
.psortKM(x, k = 20, m = 4):
[1] 17 20 20 20
.psortKM(y, k = 20, m = 4):
[1] 17 20 20 20
.psortKM(x, k = 20, m = 5):
[1] 16 17 20 20 20
.psortKM(y, k = 20, m = 5):
[1] 16 17 20 20 20
.psortKM(x, k = 21, m = 1):
[1] 21
.psortKM(y, k = 21, m = 1):
[1] 21
.psortKM(x, k = 21, m = 2):
[1] 20 21
.psortKM(y, k = 21, m = 2):
[1] 20 21
.psortKM(x, k = 21, m = 3):
[1] 20 20 21
.psortKM(y, k = 21, m = 3):
[1] 20 20 21
.psortKM(x, k = 21, m = 4):
[1] 20 20 20 21
.psortKM(y, k = 21, m = 4):
[1] 20 20 20 21
.psortKM(x, k = 21, m = 5):
[1] 17 20 20 20 21
.psortKM(y, k = 21, m = 5):
[1] 17 20 20 20 21
.psortKM(x, k = 30, m = 1):
[1] 30
.psortKM(y, k = 30, m = 1):
[1] 30
.psortKM(x, k = 30, m = 2):
[1] 29 30
.psortKM(y, k = 30, m = 2):
[1] 29 30
.psortKM(x, k = 30, m = 3):
[1] 28 29 30
.psortKM(y, k = 30, m = 3):
[1] 28 29 30
.psortKM(x, k = 30, m = 4):
[1] 27 28 29 30
.psortKM(y, k = 30, m = 4):
[1] 27 28 29 30
.psortKM(x, k = 30, m = 5):
[1] 26 27 28 29 30
.psortKM(y, k = 30, m = 5):
[1] 26 27 28 29 30
> 
> proc.time()
   user  system elapsed 
   0.20    0.03    0.20