Apache OpenOffice (AOO) Bugzilla – Issue 75281
Non-linear regressions in charts not rendered correctly.
Last modified: 2013-02-24 21:19:00 UTC
Non-linear regression curves in charts are not rendered correctly in the presence of either 0 and/or negative values in the X and/or Y value. In all cases, when a certain condition is met, the lines are rendered as flat lines at the bottom of the chart. For logarithmic regression, the condition is the presence of 0 or less (negative number) in the X set of data. For exponential regression, the condition is the presence of a negative number in the Y set of data. For power (polynomial?) regression, the condition is the presence of 0 or less (negative number) in the X set of data OR the presence of a negative number in the Y set of data. I assume it is the related to the mathematical nature of logarithms, exponents, and polynomials of the 2nd degree, but Excel seems to render the equivalent trend line correctly.
Attached is a spreadsheet file (.ods) which displays the different cases at work (9 different cases for each non-linear regression curve plus the linear curve). Additional information on the conditions are on the sheet named "Results".
Created attachment 43641 [details] Spreadsheet showing all possible cases.
Not enough research was done for this and it turns out something might have done differently Excel.
Wrong component. This is Chart. closed on request