Feature Request: Logarithmic t in parametric plots

[Christopher K. <cj...@ca...>]

Hi,

Apologies if there is already an easy way to achieve the following.

What I'm looking for is the ability to specify that the values of t for 
which x,y should be evaluated should increase logarithmically.  Even more 
useful would be the ability to do this over a range spanning from negative 
to postive aswell, e.g. -100, -10, -1, -0.1, -0.01, 0.01, 0.1, 1, 10, 100. 
Another refinement would be the ability to loop through infinity, rather 
than zero, i.e. -0.01, -0.1, -1, -10, -100, 100, 10, 1, 0.1, 0.01.

This would be particularly useful for plotting Nyquist plots, where one 
needs to plot a complex function of w, for -inf < w < inf.  If a linear 
range is used, then an awful lot of samples need to be taken to get a smooth 
curve in the regions of low w.

I'm, not sure how best this could be implemented, but one solution might be 
to add three options:

(un)set logparametric:      Instructs gnuplot to take samples of t at 
logarithmic intervals (identical to setting x axis to logarithmic in 
behaviour).

(un)set logparametricnegative      Instructs gnuplot to mirror the samples 
of t to include negative values aswell.

(un)set logparametricthroughinf      Tells gnuplot to order the samples of t 
such that they start and finish at +-0, looping through inf as opposed to 
starting and finishing at +-inf and looping through 0.


Any thoughts on whether this might be achievable?

Many thanks,

Chris Key