kcrisman wrote: > > > On Oct 13, 10:44 pm, Jason Grout <[email protected]> wrote: >> kcrisman wrote: >> >>> On Oct 13, 6:05 pm, "[email protected]" <[email protected]> wrote: >>>> Hello all, is there any other possibility how to plot implicit >>>> function than implicitplot? >>>> I do not like implicitplot too much, since it is in fact countourplot >>>> and it is not easy to set the color (for example). >>> There is not currently any other way to do this, I think. A colleague >>> of mine has some experimental code to implicit plot the "right" way >>> (by following derivatives around and spot-checking nearby to not miss >>> components, I guess), but doesn't consider it ready for prime time >>> yet. >> How do you do an implicit plot "right"? Scipy has tools for numerical >> integration (you mention following derivatives), if that helps. >> >> A quick google search turns up several references to >> software:http://geomblog.blogspot.com/2008/01/plotting-implicit-functions-bleg... >> >> The maple help page may >> help:http://www.maplesoft.com/support/help/Maple/view.aspx?path=plots/impl... >> >> This issue has come up before on the list (and Josh Kantor gave an >> algorithm and a >> reference):https://groups.google.com/group/sage-devel/browse_thread/thread/6b1d3... >> >> More references and >> algorithms:http://www.tangentspace.net/cz/archives/2007/08/implicit-plotting-cod... >> >> Mma also says: ContourPlot initially evaluates f at a grid of equally >> spaced sample points specified by PlotPoints. Then it uses an adaptive >> algorithm to subdivide at most MaxRecursion times to generate smooth >> contours.http://reference.wolfram.com/mathematica/ref/ContourPlot.html >> > > Yes to all the above.
I guess we can do a "better" job than matplotlib, as matplotlib does not have the function to go off of. In a sense, then, you are describing an adaptive evaluation of the function (at least, that's how mma seems to do it). I wonder if matplotlib can draw a contour plot from a non-rectangular grid. This sounds like an excellent project for a calc 3 student! Jason -- Jason Grout --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
