Hello,

is there a command or a procedure to draw a variety in R^3 (like V(x^2-
y-z)) with gnuplot, maxima or any other free visualization program?

The commands
load(implicit_plot);
implicit_plot (x^2-y=0, [x, -10, 10], [y, -10, 10], [gnuplot_preamble,
"set zeroaxis"]);
work well for 2D-plots with maxima.

singular.eval('ring r = 0,(x,y,z),dp;')
singular.eval('ideal I = <your variety here>;')
singular.eval('plot(I);')

On 24 Apr., 22:39, galathaea <galath...@gmail.com> wrote:

singular.eval('ring r = 0,(x,y,z),dp;')
singular.eval('ideal I = <your variety here>;')
singular.eval('plot(I);')

Thank you for the reponse. I have tried all day long but I do always
get an error when I am executing the last command
"singular.eval('plot(I);')":

type 'exceptions.RuntimeError'
...
.../Sage/local/lib/python2.5/site-packages/sage/interfaces/singular.py
in eval(self, x, allow_semicolon, strip)
421
422 if s.find("error") != -1 or s.find("Segment fault") !=
-1:
--> 423 raise RuntimeError, 'Singular error:\n%s'%s
424
425 if get_verbose() > 0:
type 'exceptions.RuntimeError'>: Singular error:
Press q to exit from 'surf'
? calling `surf` failed. (the shell return the error code 32512).
probably the executable `surf` is not found.
? error occurred in surf.lib::plot line 140: ` ERROR(err_mes);`
? leaving surf.lib::plot
skipping text from `;` error at token `)`

I don't know where the problem is. I've installed sage from the
original page and downloaded surf-1.1 with the "sage -i" command.
Although I have changed the syntax with every kind of commas " and '
and whatsoever. Everything but the above seems so work fine...

Any suggestions?

On Apr 25, 7:58 am, sanchopanch...@web.de wrote:



On 24 Apr., 22:39, galathaea <galath...@gmail.com> wrote:

singular.eval('ring r = 0,(x,y,z),dp;')
singular.eval('ideal I = <your variety here>;')
singular.eval('plot(I);')

Thank you for the reponse. I have tried all day long but I do always
get an error when I am executing the last command
"singular.eval('plot(I);')":

type 'exceptions.RuntimeError'
...
.../Sage/local/lib/python2.5/site-packages/sage/interfaces/singular.py
in eval(self, x, allow_semicolon, strip)
    421
    422         if s.find("error") != -1 or s.find("Segment fault") !> > -1:
--> 423             raise RuntimeError, 'Singular error:\n%s'%s
    424
    425         if get_verbose() > 0:
type 'exceptions.RuntimeError'>: Singular error:
Press q to exit from 'surf'
   ? calling `surf` failed. (the shell return the error code 32512).
probably the executable `surf` is not found.
   ? error occurred in surf.lib::plot line 140: `    ERROR(err_mes);`
   ? leaving surf.lib::plot
   skipping text from `;` error at token `)`

I don't know where the problem is. I've installed sage from the
original page and downloaded surf-1.1 with the "sage -i" command.
Although I have changed the syntax with every kind of commas " and '
and whatsoever. Everything but the above seems so work fine...

Any suggestions?

it looks like you may not have surf installed

the package just wraps up the singular objects into surf objects
  and sends them over to the program

if you haven't installed anything
  but the surf package from the sage site
  then this is probably what the problem is

the surf site ishttp://surf.sourceforge.net/index.shtml

if this isn't the issue
  i'm not sure what could be wrong
  and would have to troubleshoot with you

surf require gtk
  so it's not available on proprietary windowing systems
  like microsoft's

it works great on linux and mac
and i have had it working fine on fedora core 8 for some time
  if that gives a benchmark

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galathaea: prankster, fablist, magician, liar