Jason Grout wrote: > Jason Grout wrote: >> dean moore wrote: >>> I ran the code now living at < https://www.sagenb.org/home/pub/1691/ >, >>> but the function's graph >>> "wiggles," most notably by the right endpoint. Tested, both Firefox & >>> Internet Explorer. Same thing. >>> Read through < >>> http://www.sagemath.org/doc/html/ref/module-sage.plot.plot.html >, but >>> found nothing. >>> >>> I am animating a graph, so it appears in all frames. >>> >>> I fiddled a good deal, but was left wondering, "Is it weirdness with >>> SAGE, or my bad coding?" I beat >>> the problem to a snippet: >>> >>> /f = x*sin(x^2) >>> v = [] >>> for i in srange(50): >>> graph = plot(f, [-1, 3], thickness = 1, rgbcolor = (1, 0 ,0), >>> plot_points = 1000) >>> v.append(graph) >>> curve = animate(v)/ >>> /curve.show() >>> >> Wow, this is a great animation. Sorry the plotting is so distracting at >> the ends! >> >> To narrow down the issue, I executed the following after the code you gave: >> >> sage: endpoints = [v[i][0].xdata[-1] for i in srange(50)] >> sage: max(endpoints) - min(endpoints) >> 0.0039542538407206784 >> >> This computes the endpoints for the x-values that are sampled to plot >> the graph. That's quite a spread for having the exact same inputs, >> which explains the noticable wiggling. >> >> So now the question is: why in the world do we have such different >> endpoints? >> >> I might point out that the wiggling is not just at the endpoints of the >> graph. The wiggling is throughout the graph; it's just really >> noticeable at the endpoints. > > > Aha, looking at the help always helps! > > plot? has the following: > > The actual sample points are slightly randomized, so the above > plots may look slightly different each time you draw them. > > Presumably this is to avoid things like sampling the same y-value on a > periodic curve. Unfortunately, it also seems to lead to this wiggling. > > The problem in this case is that the randomness was applied to the > beginning and ending points of the interval. A patch is up at > http://trac.sagemath.org/sage_trac/ticket/2236 which fixes this issue. > The patch is just waiting for someone to referee it. Are you > comfortable doing that?
This patch has now been reviewed and merged into the next version of Sage (due in a few short hours). Your example should look much better then. Jason --~--~---------~--~----~------------~-------~--~----~ 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 URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
