This calculated field in Tableau includes a debugging function that outputs the data being sent to and from RServe.

TableauR_debug.txt

IF FIRST() == 0 THEN
SCRIPT_REAL('
debug <- TRUE
 
## R Comment
  results <- mean(.arg1)
## Debug output
if (debug) {
  sink("TableauR_debug.txt", append=TRUE)
  print("######## START ####")
  print("######## Arithmetic LOS")
  print(date())
  print("incoming from Tableau")
  print(.arg1)
  print("back to Tableau")
  str(results)
  results
  print("######## END ####")
  print("")
 
  sink()
}
 
results
',
SUM([LOS]) //.arg1
)
END