Version: (using Devel) OS: Linux Installed from: Compiled sources PROBLEM: fit linear plugin cannot produce fit result when one or more points are not valid STEPS TO REPRODUCE: 1. Create 3 vectors X, Y, DelY from source file 'fittest.dat' located in graphics/kst/tests/data_files Data --> New Vector... configure: data starts at line 0 (by doing so, the first point of all 3 vectors will be invalid) 2. construct a curve 1.Data --> New Curve... Choose X from the drop-down list for the X axis vector Choose Y from the drop-down list for the Y axis vector Choose DelY from the drop-down list for the +Y error bar Check Show points in the Appearance panel Create a new tab: “fitting demo” from the New... button in the Placement panel Click OK to view the curve 3. curve fitting Click anywhere on the plot Choose Fit --> Y in the appearing context menu Choose Fit linear(v0.1) in the drop down list of Plugin Selection Click OK RESULTS: no fit result EXPECTED RESULTS: the plugin should ignore these invalid points. The 'fit linear weighted' plugin is able to ignore these invalid points and produce a result in this case.
The linear fit, as expected, does not work for vectors with NaN values. The weighted linear fit works only in that the NaN value's contriubution to the fit is driven to zero by the corrresponding NaN weight. Attempting a weighted linear fit with a NaN value and corresponding non-NaN weight will also "not work". All of this is expected behaviour.