On Thu, Nov 20, 2008 at 7:21 AM, kcrisman <[EMAIL PROTECTED]> wrote: > > > >> >> > I am really newbie to Sage, but I need to both plot and declare >> > functions like: >> > f(x,y,z) = x*y*z >> > and other poly's containing 3 variables. >> > How do I do that? >> > > It sounds like you are looking for a 3-D implicit plot. Is that > correct? Or perhaps a contour plot in 3-D. Unfortunately, although > there are reasonable (though not perfect) 2-D versions of that in > Sage, I do not believe that we have native implicit plotting or > contour plotting available in Sage in 3-D. That would be really nice, > but I don't even pretend to understand how the code might be improved > to implement that. > > However, there is the optional experimental package for Surf, which I > believe does plot surfaces (in an algebraic geometry context - their > home page has a nice shot of the 27 lines on a cubic) and can be used > with Sage. The documentation about that on the Sage site does not > inspire confidence that this can effortlessly installed, > unfortunately. > > Best, > - kcrisman
This is just to confirm that indeed Sage doesn't have an implementation of implicit 3d plots yet. There is a very powerful/flexible list_plot3d command -- you can pass it an arbitrary collection of points in 3d and it puts a surface through them using various interpolation options. Thus you could get some approximation to an implicit plot, by finding lots of points (x,y,z) in a 3d grid (use fast_float to make this fast) such that f(x,y,z) is tiny. That would be just a few lines of code to implement, and might be a reasonable approximation to 3d implicit plots, for some applications (??). William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
