Getting the output of a script in Matlab called from R - r

Question

I am trying to call a very simple script in Matlab from RStudio. However, whenever I run the following code, without getting any error, it will return 0 to me. Would you please let me know how I can call Matlab scripts in R and get their outputs?
run_matlab_script("C:/Users/XXX/Desktop/Sum.m", verbose = TRUE, desktop = FALSE, splash = FALSE,
display = TRUE, wait = TRUE, single_thread = FALSE)
Note that to use the above function, I am using "matlabr" package in r. Moreover, my simple script in Matlab includes the below code:
b=1+2
Thanks in advance!

Answer 1

matlab::run_matlab_script uses system to call matlab. As of today, that function (current commit is c01d310) looks like:
run_matlab_script = function(
fname,
verbose = TRUE,
desktop = FALSE,
splash = FALSE,
display = FALSE,
wait = TRUE,
single_thread = FALSE,
...){
stopifnot(file.exists(fname))
matcmd = get_matlab(
desktop = desktop,
splash = splash,
display = display,
wait = wait,
single_thread = single_thread)
cmd = paste0(' "', "try, run('", fname, "'); ",
"catch err, disp(err.message); ",
"exit(1); end; exit(0);", '"')
cmd = paste0(matcmd, cmd)
if (verbose) {
message("Command run is:")
message(cmd)
}
x <- system(cmd, wait = wait, ...)
return(x)
}
Noteworthy (to me) is that run_matlab_script includes ... in its formals, and passes that unchanged to system. In fact, its help documentation specifically says that is what it does:
#' #param ... Options passed to \code{\link{system}}
Because of this, we can try to capture its output by looking at system. From ?system,
intern: a logical (not 'NA') which indicates whether to capture the
output of the command as an R character vector.
which suggests that if you change your call to
ret <- run_matlab_script("C:/Users/XXX/Desktop/Sum.m", verbose = TRUE, desktop = FALSE,
splash = FALSE, display = TRUE, wait = TRUE, single_thread = FALSE,
intern = TRUE)
you will get its output in out.