https://bugs.kde.org/show_bug.cgi?id=455808
--- Comment #3 from Larry <ljbe...@zoho.com> --- Sorry, minor correct to last e-mail: if I change C2 to -1 I get an upside down parabola for the best fit, but the values are in the -2500 range instead of 12 and do not fit my data. Changing C1 to -1 changes the best fit curve very little. Larry ---- On Wed, 22 Jun 2022 13:22:40 -0700 Alexander Semke <bugzilla_nore...@kde.org> wrote --- https://bugs.kde.org/show_bug.cgi?id=455808 --- Comment #1 from Alexander Semke <mailto:alexander.se...@web.de> --- (In reply to Larry from comment #0) > Created attachment 150065 [details] > Shows unexpected best-fit curve > > SUMMARY > *** > Unable to produce a best-fit curve to a negative polynomial shape data > (upside down U shape). > *** > Data: > 50, 10.9 > 40, 12.4 > 30, 18.9 > 20, 25.5 > 10, 27.4 > 0, 28.8 > -10, 27.9 > -20, 23.4 > -30, 21.6 > -40, 16.8 > -50, 12.9 The initial start values for the parameters seem to block the algorithm to converge to the proper solution. Since you have this upside-down parabola like data, just set the start value for the second parameter, i.e. for c1 to -1 and try to re-fit again. You get the proper fit to your data with it. Does it also work for you with c1 = -1? -- You are receiving this mail because: You are watching all bug changes.
