R from Perl -- RSPerl and lines function.

  The thing that comes to mind initially is an issue with the
event loop.  Perl is not running an X windows event loop,
so not all the updates, refreshes, and drawing events are
being processed.   R is processing some of them in the
drawing calls, but after that R does not get an opportunity
to process any more.

 As I say, this is just a guess.  To validate it, try using
a non-interactive graphics device such as pdf, e.g.


&R::call('pdf', 'foo.pdf');


&R::callWithNames("hist", {'', \@Rdata, 'main', '', 'xlab',
"Distribution of the distances between oligo-5' and sequence 3'",
'br', 15, 'col', 'gray', 'prob', 'T'} );

&R::call("lines", ("density", \@Rdata)) );

&R::call('dev.off');

And then examine that file to ensure it has the lines.

If it does, then it is an issue with the interactive
device and the event loop is almost definitely the problem.

How to fix things if the event loop is the problem  is
not trivial and there are many possible different situations
to consider.

 D.


Florence Combes wrote:

Dear R-helpers,

I am running well Perl and R on my Debian Linux, and I tried RSPerl.
Installation is ok and all simple functions run well. But I have a
problem to call the "lines" function.
I would like to draw an histogram with the density curve on. Is is OK
in R with the command:

x<-rnorm(1000)
hist(x,prob=T)
lines(density(x))

for example.

Now, I have a Perl script with which  pars files, and I obtain data in
a list @distance. I draw an hist with RSPerl command (from Perl):

--------------------------
(---Perl script---)

&R::initR("--silent");
&R::library("RSPerl");
@Rdata=&R::call("as.numeric", \@distance);

&R::callWithNames("hist", {'', \@Rdata, 'main', '', 'xlab',
"Distribution of the distances between oligo-5' and sequence 3'",
'br', 15, 'col', 'gray', 'prob', 'T'} );

&R::call("lines", ("density", \@Rdata)) );

sleep(4);

&R::call("dev.off");

exit;
-----------------------------

All runs well: I obtained the histogram graph, and it seems that the
density call runs well since I have the message
"Performed the call, result has length 7"
and I read the density fuction results in 7 parameters;
but just after I have a message like "segmentation fault".

I cannot understand what happens ?

Has someone already encountered this problem or know how to abtain an
histogram and the density line with RSPerl ???

Thanks a lot for your help, caus I tried all I could think of ...

Florence.

--
Duncan Temple Lang                duncan at wald.ucdavis.edu
Department of Statistics          work:  (530) 752-4782
371 Kerr Hall                     fax:   (530) 752-7099
One Shields Ave.
University of California at Davis
Davis, CA 95616, USA