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integer64: random numbers

Source: R/hash64.R
runif64.Rd

Create uniform random 64-bit integers within defined range

Usage

runif64(
  n,
  min = lim.integer64()[1L],
  max = lim.integer64()[2L],
  replace = TRUE
)

Arguments

n

length of return vector

min

lower inclusive bound for random numbers

max

upper inclusive bound for random numbers

replace

set to FALSE for sampleing from a finite pool, see sample()

Value

a integer64 vector

Details

For each random integer we call R's internal C interface unif_rand() twice. Each call is mapped to 2^32 unsigned integers. The two 32-bit patterns are concatenated to form the new integer64. This process is repeated until the result is not a NA_INTEGER64_.

See also

runif(), hashfun()

Examples

  runif64(12)
#> integer64
#>  [1] 2915658457812729556  -3491511829406696631 -3496825464828931785
#>  [4] 5395852077839172502  -7835456012596746149 -1516745570522234364
#>  [7] -6832279058283761012 3129987699866411399  -1425688589184971166
#> [10] 1743351634359137850  -619044005758770366  -8343468749812013056
  runif64(12, -16, 16)
#> integer64
#>  [1] 9   -9  13  8   -10 0   5   14  9   3   -7  -2 
  runif64(12, 0, as.integer64(2^60)-1)  # not 2^60-1 !
#> integer64
#>  [1] 896499375407589580 799359046121395853 960877807272653955
#>  [4] 733002594872096801 750278469790426764 288656285354523678
#>  [7] 138536448177156874 133560880250517603 449130193256833291
#> [10] 972719265714589958 9862525313230357   403081621054673484
  var(runif(1e4))
#> [1] 0.08441354
  var(as.double(runif64(1e4, 0, 2^40))/2^40)  # ~ = 1/12 = .08333
#> [1] 0.08380791

  table(sample(16, replace=FALSE))
#> 
#>  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 
#>  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1 
  table(runif64(16, 1, 16, replace=FALSE))
#> 
#>  2  3  4  5  8 10 11 12 14 15 16 
#>  1  2  1  1  1  1  1  3  2  1  2 
  table(sample(16, replace=TRUE))
#> 
#>  1  3  6  8  9 10 12 13 14 15 16 
#>  2  1  2  1  1  1  1  2  2  1  2 
  table(runif64(16, 1, 16, replace=TRUE))
#> 
#>  1  2  5  7  8 10 12 13 14 16 
#>  1  2  2  1  1  2  2  1  2  2