Produce table with contour_plot




On Mon, 29 Nov 2010, Dan wrote:

< 
< Dear All,
< 
< The following
< 
< f(x,y) := x^2+y^2-1 ;
< contour_plot(f(x,y),[x,-1.5,1.5],[y,-1.5,1.5],[gnuplot_preamble, "set
< cntrparam levels discrete 0.0"]) ;
< 
< produces a nice-looking plot of the unit circle.  However, if I thn
< decide I want the (x,y) values on the contour in a
< whitespace-separated table and issue
< 
< contour_plot(f(x,y),[x,-1.5,1.5],[y,-1.5,1.5],[gnuplot_preamble, "set table
< 'circletable.dat'; set cntrparam levels discrete 0.0"]) ;
< 
< the file circletable.dat is created, but is empty.  Any ideas, please?
 
 Dan,
 When I run the command above, the file is created and filled.
 I'm using Maxima 5.22.1 and Gnuplot 4.4.0 on Debian testing.

 What version of Maxima are you using?

 Leo

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