Does anyone know if there's a reason that proc.time() uses cat()
rather than message() to print the output when there has been an error
in the process of timing?
line 31 of time.R,
https://github.com/wch/r-source/blob/e5b21d0397c607883ff25cca379687b86933d730/src/library/base/R/time.R#L31
on.exit(cat("Timing stopped at:", ppt(proc.time() - time),
"\n"))
This means that as far as I can tell the general way to make sure
there is no output from a timed statement is ...
tt1 <- capture.output(tt0 <- suppressMessages(suppressWarnings(
try(<stuff to try>,
silent=TRUE))))
(I know I could/should be using tryCatch() instead of try(), but I don't
think it really matters here ... ?)
What would people think of a request to change this to message()
rather than cat() in the future ... ? (This would mess up code that is
already using capture.output() to store this information ...)
cheers
Ben Bolker
Hi Ben (and everyone else), as this did not attract attention yet, let me start>>>>> Ben Bolker <bbolker at gmail.com> >>>>> on Mon, 4 Jul 2016 11:49:40 -0400 writes:> Does anyone know if there's a reason that proc.time() uses cat() > rather than message() to print the output when there has been an error > in the process of timing? This is really not about proc.time(), but about system.time() [ and I have corrected the 'Subject' accordingly ] .. > line 31 of time.R, > https://github.com/wch/r-source/blob/e5b21d0397c607883ff25cca379687b86933d730/src/library/base/R/time.R#L31 > on.exit(cat("Timing stopped at:", ppt(proc.time() - time), "\n")) > This means that as far as I can tell the general way to make sure > there is no output from a timed statement is ... > tt1 <- capture.output(tt0 <- suppressMessages(suppressWarnings( > try(<stuff to try>, silent=TRUE)))) > (I know I could/should be using tryCatch() instead of try(), but I don't > think it really matters here ... ?) > What would people think of a request to change this to message() > rather than cat() in the future ... ? (This would mess up code that is > already using capture.output() to store this information ...) [I think that (last issue) would be acceptable.] One reason of the current cat() may just be historical: message() did not exist yet when system.time() was created. However, I agree that that is not good enough a reason to keep it. Much more important is the fact that it is *nice* that the message Timing stopped at: ... is printed in many cases when a system.time()d call is stopped early. Quite often for me this is *not* when an error happens as your suppress*() contortions (;-) suggest, but rather when I interrupt the long lasting call. And the current setup nicely gives > i <- 0; system.time( while(TRUE) i <- i+1 ) C-c C-c Timing stopped at: 1.001 0.084 1.086 > However, at least this simple case, also works fine with message() instead of cat() ... as I just tried now. A harder case are the "bad errors", e.g., memory overflow and similar bad things... cat() seems to be pretty robust, where as message() does invoke a handler (exactly *why* you want it, right?) and that may be harder to keep working correctly after certain errors than a simple cat(). I hope that some real experts (on "context switching", "long jumps", etc) would chime in now. Martin
On Fri, 15 Jul 2016, Martin Maechler wrote:> Hi Ben (and everyone else), > > as this did not attract attention yet, let me start > >>>>>> Ben Bolker <bbolker at gmail.com> >>>>>> on Mon, 4 Jul 2016 11:49:40 -0400 writes: > > > Does anyone know if there's a reason that proc.time() uses cat() > > rather than message() to print the output when there has been an error > > in the process of timing? > > This is really not about proc.time(), but about system.time() > [ and I have corrected the 'Subject' accordingly ] .. > > > line 31 of time.R, > > > https://github.com/wch/r-source/blob/e5b21d0397c607883ff25cca379687b86933d730/src/library/base/R/time.R#L31 > > > on.exit(cat("Timing stopped at:", ppt(proc.time() - time), "\n")) > > > This means that as far as I can tell the general way to make sure > > there is no output from a timed statement is ... > > > tt1 <- capture.output(tt0 <- suppressMessages(suppressWarnings( > > try(<stuff to try>, silent=TRUE)))) > > > (I know I could/should be using tryCatch() instead of try(), but I don't > > think it really matters here ... ?) > > > What would people think of a request to change this to message() > > rather than cat() in the future ... ? (This would mess up code that is > > already using capture.output() to store this information ...) > > [I think that (last issue) would be acceptable.] > > One reason of the current cat() may just be historical: > message() did not exist yet when system.time() was created. > However, I agree that that is not good enough a reason to keep > it. Much more important is the fact that it is *nice* that the > message > > Timing stopped at: ... > > is printed in many cases when a system.time()d call is stopped > early. Quite often for me this is *not* when an error happens > as your suppress*() contortions (;-) suggest, but rather when I > interrupt the long lasting call. > And the current setup nicely gives > > > i <- 0; system.time( while(TRUE) i <- i+1 ) > C-c C-c > Timing stopped at: 1.001 0.084 1.086 > > > > > However, at least this simple case, also works fine with > message() instead of cat() ... as I just tried now. > > A harder case are the "bad errors", e.g., memory overflow and > similar bad things... > cat() seems to be pretty robust, where as message() does invoke > a handler (exactly *why* you want it, right?) and that may be > harder to keep working correctly after certain errors than a > simple cat(). > > I hope that some real experts (on "context switching", "long > jumps", etc) would chime in now.I don't have a strong opinion on whether message would be better or not. But now that the on.exit code is executed after unwinding the C call back to the point of the system.time call there is no longer such a robustness issue. Best, luke> > Martin > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel >-- Luke Tierney Ralph E. Wareham Professor of Mathematical Sciences University of Iowa Phone: 319-335-3386 Department of Statistics and Fax: 319-335-3017 Actuarial Science 241 Schaeffer Hall email: luke-tierney at uiowa.edu Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu