5
$\begingroup$

RegionPlot appears to have regressed in version 10.4

In 10.3.1

RegionPlot[ImplicitRegion[x^2 + y^2 == 1, {x, y}]]

gives

enter image description here

But in 10.4 both

RegionPlot[ImplicitRegion[x^2 + y^2 == 1, {x, y}]]

and

RegionPlot[x^2 + y^2 == 1, {x, -1, 1}, {y, -1, 1}]

give

enter image description here

However, 10.4 knows that this is a valid region.

DiscretizeRegion@ImplicitRegion[x^2 + y^2 == 1, {x, y}]

enter image description here

Can anyone else confirm this?

Win 7 Pro 64 bit.

$\endgroup$
  • 1
    $\begingroup$ Same on linux, however RegionPlot[0.99 <= x^2 + y^2 <= 1.01, {x, -1, 1}, {y, -1, 1}, PlotPoints -> 200] this works. $\endgroup$ – b.gates.you.know.what Mar 6 '16 at 10:59
  • $\begingroup$ I sent product feedback to Wolfram Tech Support on this issue. $\endgroup$ – Bob Hanlon Mar 6 '16 at 14:39
  • $\begingroup$ This could just be a case of the function catching up with the documentation, as the help page for RegionPlot in both versions states "RegionPlot can in general only find regions of positive measure; it cannot find regions that are just lines or points" $\endgroup$ – Jason B. Apr 8 '16 at 9:46
4
$\begingroup$

This is not an answer but rather an extended comment demonstrating another aspect of the problem.

$Version

(*  "10.4.0 for Mac OS X x86 (64-bit) (February 26, 2016)"  *)

If the region is given some thickness it is displayed:

Manipulate[RegionPlot[
  ImplicitRegion[1 - 10^(-n) <= x^2 + y^2 <= 1 + 10^(-n), {x, y}]], {{n, 7}, 
  Range[10], ControlType -> SetterBar}]

enter image description here

However, when the thickness is made too small, another problem arises: the region displays as if it were a disk.

enter image description here

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.