plotting modulus of complex function



On 2012-05-03, Bart Vandewoestyne <Bart.Vandewoestyne at telenet.be> wrote:

> Unfortunately, this fails.  I get the error:
>
> (%i18) plot2d(float(abs(Gm(s))),[s,0.1,1000.0])
> Maxima encountered a Lisp error:
>    Couldn't write to #<SB-SYS:FD-STREAM for "descriptor 9" {10061923A1}>:
>      Broken pipe

Your example bartfile.mac works OK for me. I am working w/ Maxima 5.26.0
and approximately 5.27.0 (built from Git) on Linux.

I suspect the broken pipe means that Maxima failed to launch Gnuplot (so
there is nobody to listen to the plotting commands Maxima wants to
send). By default the plot format is gnuplot_pipes; try

  set_plot_option ([plot_format, gnuplot]);

(writes a file instead of opening a pipe), or

  set_plot_option ([plot_format, openmath]);

Openmath format uses a Tcl/Tk widget.

By the way, can you launch gnuplot from the command line?
(Maybe Gnuplot is not installed on your system?)

Hope this helps,

Robert Dodier