R help - Mar 2007 - Generating R plots through Perl

Hello,

I am in the process of writing a Perl program to carry out and analyze
large numbers of regressions using R as the regression engine, and I am
using Statistics::R to create the communication bridge between the two
programs.  Statistics::R creates a pipe between R and Perl and uses
Rterm.exe (hidden during run-time) to carry out the R commands.  This
communication bridge works well for creating regression objects in R and
analyzing some of the regression results.  However, I have not been able
to create a plot using this method.  The plot commands that are executed
in R through Perl (see below) produce a pdf file with no data (i.e. the
plot data is not getting passed to the file).  It seems that the pipe
connection created via Statistics::R cannot produce a graphics device
window to save.  A very simple version of the commands that I am using
in my Perl program are as follows:

$R->send(qq (xVal <- c(1,2,3,4,5,6)));
$R->send(qq (yVal <- c(3,5,2,6,1,5)));  
$R->send(qq (pdf("C:/Test Environment/R/perlPlotTest.pdf")));
$R->send(qq (plot(xVal, yVal)));
$R->send(qq (graphics.off()));

As the code indicates, I am using R's pdf function to create a pdf file
containing the plot of xVal and yVal.  I am using the graphics.off()
function rather than the dev.off() function as I get an error message of
"<simpleError in dev.off(): cannot shut down device 1 (the null
device)>" when dev.off() is used.  Is there another way to generate and
save a plot using the bridge connection that I described?  If not, what
would be an efficient way of generating and saving plots from within my
Perl program?  Any help would be greatly appreciated.

Thank you,
Ryan



	[[alternative HTML version deleted]]

On Mar 1, 2007, at 6:28 PM, <Ryan.G.Huckstorf at wellsfargo.com> wrote:

First off, if you are working in perl you might want to be aware of  
ruby and the "r for ruby" project:
http://rubyforge.org/projects/r4ruby/
> Hello,
>
> $R->send(qq (xVal <- c(1,2,3,4,5,6)));
> $R->send(qq (yVal <- c(3,5,2,6,1,5)));
> $R->send(qq (pdf("C:/Test Environment/R/perlPlotTest.pdf")));
> $R->send(qq (plot(xVal, yVal)));
> $R->send(qq (graphics.off()));
I don't really know how to write this in perl, but could you perhaps  
put the last three lines all in one call to "$R->send", using
dev.off
() then? Don't know if it would make a difference, but that's the  
only thing I could think of. I'm guessing something like this:

$R->send(qq (pdf("C:/Test Environment/R/perlPlotTest.pdf"); plot 
(xVal, yVal); dev.off()));
> As the code indicates, I am using R's pdf function to create a pdf  
> file
> containing the plot of xVal and yVal.  I am using the graphics.off()
> function rather than the dev.off() function as I get an error  
> message of
> "<simpleError in dev.off(): cannot shut down device 1 (the null
> device)>" when dev.off() is used.  Is there another way to generate
> and
> save a plot using the bridge connection that I described?  If not,  
> what
> would be an efficient way of generating and saving plots from  
> within my
> Perl program?  Any help would be greatly appreciated.
>
> Thank you,
> Ryan
Haris Skiadas
Department of Mathematics and Computer Science
Hanover College