Re: nonlinear3.dem is very slow on aqua terminal

[Daniel J S. <dan...@ie...>]

On 07/17/2016 11:34 AM, Jun T. wrote:
>
> 2016/07/16 15:20, Daniel J Sebald <dan...@ie...> wrote:
>
>> Does the 'image.dem' example take so long as well?,
>
> No, it works normally.
>
> I think use of the 'pixels' keyword in probably_tux.dem is causing
> the slowness. If I remove the 'pixels' from the last line of
> probably_tux.dem then nonlinear3.dem ends quickly, but the nonlinear
> axis scaling does not work anymore.

Ah, yes, the vector-based pixels, but that is contrary to what you had 
concluded.  In that mode, gnuplot is not using bitmap graphics, but 
vector graphics (think of a pixel as being a rectangle...or 
parallelogram if rotated in space).  But why so long?  There is an 
example in image.dem that I think falls back to vector-based.  Also 
'image2.dem' has several of those.  Anything where the image is 
projected non-parallel to the viewing plane will fall back to drawing 
polygons for pixels.


>> Could your computer be running low on memory causing your system to use disk swap?
>
> No, my Mac has enough free memory while running the demos.
> It seems gnuplot uses about 0.5GB of memory for nonlinear3.dem.

Right.  That isn't the issue.

I'm still surprised that this takes so long.  If none of the demos in 
'image.dem' and 'image2.dem' are glacial-pace slow, then I wonder if 
something is happening in which the nonlinearity creates a rectangular 
with peculiar coordinates that causes an algorithm aqua is using to veer 
off course.

What happens if you temporarily make this change in probably_tux.dem:

#f(x) = norm((x-center)/sigma)
#g(x) = sigma*invnorm(x)+center
f(x) = x
g(x) = x

Dan