D24972: Keep cumulated error negligible for rapidly increasing functions

[Yuri Chornoivan]

yurchor created this revision.
yurchor added a reviewer: KDE Edu.
Herald added a project: KDE Edu.
Herald added a subscriber: kde-edu.
yurchor requested review of this revision.

REVISION SUMMARY
  The current scheme violates Runge-Kutta condition on error O(h^4) when dy is too high. This leads to visible shifting and discontinuities on the plots of integrals for e^x^2, e^abs(x), etc.
  
  BUG: 341256

TEST PLAN
  1. Compile and install KmPlot.
  2. Create the Cartesian plot "f(x) = e^x^2".
  3. Switch to the "Integral" tab and tick the "Show integral" item.
  4. Try to change the scale (Ctrl+mouse wheel). The integral curve should be plotted as expected (no discontinuities, no extra lines on Ox).

REPOSITORY
  R334 KmPlot

BRANCH
  master

REVISION DETAIL
  https://phabricator.kde.org/D24972

AFFECTED FILES
  kmplot/xparser.cpp

To: yurchor, #kde_edu
Cc: kde-edu, narvaez, apol
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.kde.org/pipermail/kde-edu/attachments/20191026/7295df1c/attachment-0001.html>