Re: direction field in gnuplot

[<HBB...@t-...>]

Leo wrote:

> Jaime E. Villate replied on the issue of direction field and gnuplot
> in maxima here:
> http://thread.gmane.org/gmane.comp.mathematics.maxima.general/13159/focus=13255

With all due respect, I'm not sure it's worth arguing with somebody who 
judges a web-page showing three plots only by the contents of the first. 
  Yes, there's is a plot of equipotential lines in the vectors.dem.  No, 
that doesn't disprove gnuplot's ability to do direction fields.

The actual direction fields to be seen in the referenced URL:

> http://maxima.sourceforge.net/docs/manual/en/maxima_63.html#SEC228.

can all be done easily using gnuplot.  These direction fields are, 
indeed, just a subclass of vector fields (limited by all vectors being 
unit-length).  gnuplot won't do numerical integration because gnuplot is 
a plotting program, not a number crunching engine.  But if maxima cared 
doing the integration and handing out the resulting curve as another 
data set, it's not at all hard to generate that plot using gnuplot. 
With maxima in the background and the more recent additions to mouse 
interaction in gnuplot, I expect someone could even imitate that "draw a 
field line by picking a point on it" gimmick.