Smooth histograms

[Philipp K. J. <ja...@ie...>]

I just submitted a patch (1970923) which
draws a smooth histogram-like curve
for a random collection of points, using
a Gaussian kernel density estimation
algorithm.

Demos are found here:
	www.philipp-janert.com/kdensity

The new method has the following advantages
over the classic way of generating histograms
using "smooth frequency":
- the resulting histogram is a smooth curve,
	making the effect of binning less severe
- it handles intermediate "bins" with no points
	in them gracefully. (smooth freq does so
	only if used "with boxes", but if you use 
	"with lines" for example, the line will not
	drop to zero if an intermediate bin is
	empty)

The method is invoked like a weighted smoothing
algorithm:
	plot "data" u 1:(1):(1) smooth kdensity
where the 2nd parameter is the weight of each
point and the 3rd parameter is the bandwidth
to be used.

This patch complements the "smooth cumulative"
algorithm as another way to visualize the 
distribution of a collection of random points.

Comments and suggestions are welcome.

Best,

		Ph.