Warning messages:
1: In .Internal(gc(verbose, reset, full)) :
  closing unused connection 13 (<-localhost.localdomain:11177)
2: In .Internal(gc(verbose, reset, full)) :
  closing unused connection 12 (<-localhost.localdomain:11177)
3: In .Internal(gc(verbose, reset, full)) :
  closing unused connection 11 (<-localhost.localdomain:11177)
4: In .Internal(gc(verbose, reset, full)) :
  closing unused connection 10 (<-localhost.localdomain:11177)
5: In .Internal(gc(verbose, reset, full)) :
  closing unused connection 9 (<-localhost.localdomain:11177)
6: In .Internal(gc(verbose, reset, full)) :
  closing unused connection 8 (<-localhost.localdomain:11177)
7: In .Internal(gc(verbose, reset, full)) :
  closing unused connection 7 (<-localhost.localdomain:11177)
8: In .Internal(gc(verbose, reset, full)) :
  closing unused connection 6 (<-localhost.localdomain:11177)
9: In .Internal(gc(verbose, reset, full)) :
  closing unused connection 5 (<-localhost.localdomain:11177)
10: In .Internal(gc(verbose, reset, full)) :
  closing unused connection 4 (<-localhost.localdomain:11177)
Error in { : task 1 failed - "non-numeric argument to binary operator"
Calls: %dopar% -> <Anonymous>
Execution halted