Re: [PATCH] New pm3d corners2color function

[sfeam (E. Merritt) <eam...@gm...>]

On Thursday, 04 October 2012, Clement Law wrote:
> I've written a small patch[a] that adds a harmonic mean function[1] to
> pm3d corners2color. 
> 
> set pm3d corners2color harmean
> 
> The reason why I added another 'mean' function is to complete the set.
> Gnuplot at the moment as two of the three 'pythagorean means'[2]. The
> harmonic mean is useful as it can offer a truer sense of the average.
> See this physics example [3].
> 
> Clement Law

I have a related question.

There is an option "set pm3d interpolate <xdelta>,<ydelta>" that 
produces smoother coloring subdividing each quadrangle into smaller
quadrangles with individually calculated color values.  But these
color values are always assign by linear interpolation.

For color schemes c1/c2/c3/c4/mean this comes out equivalent to the 
same overall coloring applied to a finer grid of x,y values.  The
finer the interpolation, the closer it comes to a true linear color
gradient.

However, for color schemes using the harmonic or geometric mean,
the finer grid still results in a linear color gradient rather than
the requested geometric or harmonic color variation.  Shouldn't the
interpolation in these cases be some non-linear function?
What function would that be?

	Ethan