Package check result: ERROR

Check: examples, Result: ERROR
  Running examples in ‘aramappings-Ex.R’ failed
  The error most likely occurred in:
  
  > base::assign(".ptime", proc.time(), pos = "CheckExEnv")
  > ### Name: ara_exact_l1
  > ### Title: Exact Adaptable Radial Axes (ARA) mappings using the L1 norm
  > ### Aliases: ara_exact_l1
  > 
  > ### ** Examples
  > 
  > # Define subset of (numerical) variables of the auto_mpg dataset
  > # 1:"mpg", 4:"horsepower", 5:"weight", 6:"acceleration"
  > selected_variables <- c(1, 4, 5, 6)
  > n <- length(selected_variables)
  > 
  > # Retain only selected variables and rename dataset as X
  > X <- auto_mpg[, selected_variables] # Select a subset of variables
  > 
  > # Remove rows with missing values from X
  > N <- nrow(X)
  > rows_to_delete <- NULL
  > for (i in 1:N) {
  +   if (sum(is.na(X[i, ])) > 0) {
  +     rows_to_delete <- c(rows_to_delete, -i)
  +   }
  + }
  > X <- X[rows_to_delete, ]
  > 
  > # Convert X to matrix
  > X <- apply(as.matrix.noquote(X), 2, as.numeric)
  > 
  > # Standardize data
  > Z <- scale(X)
  > 
  > # Define axis vectors (2-dimensional in this example)
  > r <- c(0.8, 1, 1.2, 1)
  > theta <- c(225, 100, 315, 80) * 2 * pi / 360
  > V <- pracma::zeros(n, 2)
  > for (i in 1:n) {
  +   V[i,1] <- r[i] * cos(theta[i])
  +   V[i,2] <- r[i] * sin(theta[i])
  + }
  > 
  > # Select variable for exact estimates, and use it for coloring the embedded
  > # points
  > variable <- sample(1:n, 1)
  > 
  > # Detect the number of available CPU cores
  > if (requireNamespace("parallelly", quietly = TRUE)) {
  +   NCORES <- parallelly::availableCores(omit = 1)
  + } else {
  +   NCORES <- parallel::detectCores() - 1
  + }
  > 
  > # Create a cluster for parallel processing
  > cl <- parallel::makeCluster(NCORES)
  Error in .check_ncores(length(names)) : 31 simultaneous processes spawned
  Calls: <Anonymous> -> makePSOCKcluster -> .check_ncores
  Execution halted

Check: tests, Result: ERROR
    Running ‘testthat.R’ [39s/39s]
  Running the tests in ‘tests/testthat.R’ failed.
  Complete output:
    > # This file is part of the standard setup for testthat.
    > # It is recommended that you do not modify it.
    > #
    > # Where should you do additional test configuration?
    > # Learn more about the roles of various files in:
    > # * https://r-pkgs.org/testing-design.html#sec-tests-files-overview
    > # * https://testthat.r-lib.org/articles/special-files.html
    > 
    > library(testthat)
    > library(aramappings)
    > 
    > test_check("aramappings")
    Saving _problems/test-ara_exact_l1-201.R
    [ FAIL 1 | WARN 0 | SKIP 3 | PASS 344 ]
    
    ══ Skipped tests (3) ═══════════════════════════════════════════════════════════
    • {parallelly} is not installed. (3): 'test-ara_exact_linf.R:189:1',
      'test-ara_unconstrained_l1.R:198:1', 'test-ara_unconstrained_linf.R:199:1'
    
    ══ Failed tests ════════════════════════════════════════════════════════════════
    ── Error ('test-ara_exact_l1.R:201:1'): (code run outside of `test_that()`) ────
    Error in `.check_ncores(length(names))`: 31 simultaneous processes spawned
    Backtrace:
        ▆
     1. └─parallel::makeCluster(NCORES) at test-ara_exact_l1.R:201:1
     2.   └─parallel::makePSOCKcluster(names = spec, ...)
     3.     └─parallel:::.check_ncores(length(names))
    
    [ FAIL 1 | WARN 0 | SKIP 3 | PASS 344 ]
    Error:
    ! Test failures.
    Execution halted