On Wed, 25 Jun 2014, Andreï wrote:
 Dear gentlemen and ladies,
 After some extensive work with scripts, I was a bit frustrated when I
 figured out that plots brought onto display via
 gnuplot STUFF --output=display
 are shut down after the *nulldata* command. Consider the following example:
 <hansl>
 nulldata 50
 set seed 20140624
 series x = sort(randgen(u,0,10))
 set seed 20140625
 series normerr = randgen(n,0,1)
 set seed 2024
 series baderr = randgen(t,1)
 series y = 2+0.5*x + (index>40 ? baderr : normerr)
 # Let's look at those odious outliers
 gnuplot y x --output=display --linear-fit
 # Bootstrap
 matrix Y = y
 matrix X = x
 matrix DATA = Y~ones(50,1)~X
 scalar iters = 100000
 matrix betas = zeros(iters,2)
 loop i=1..iters --progressive --quiet
    matrix D = resample(DATA)
    betas[i,] = mols(D[,1], D[,2:3])'
 endloop
 nulldata iters --preserve
 # Because kdensity does not favour matrices, series only!
 series bs2 = betas[,2]
 matrix ker2 = kdensity(bs2)
 gnuplot 2 1 --matrix=ker2 --with-lines --suppress-fitted --output=display
 </hansl>
 As you can see, the desired output consists of two plots, the scatterplot
 and the bootstrap distribution of the coefficient. However, much as I would
 like to look at them side-by-side, it is impossible since the *nulldata*
 command eliminates the original series and somehow closes the plot window
 (verified via console, too). So things go smoothly as long as we use the
 same dataset, but even the preservation of matrices does not prevent the
 plot window from being shut down. Is it a bug or a feature? Can such
 forceful behaviour be somehow overridden? 
I take your point, Andrei Viktorovich. It seems that the --preserve 
flag should probably preserve plots as well as matrices and the 
like. I'll look into that.
Besides, I don't see any real reason why kdensity() shouldn't handle 
a vector as well as a series.
Allin Cottrell