CAPE-OPEN

In attempting to plot surface tension data, whenever the [Fit] button is selected, the plot y-axis range reverts to 0.07 to 0.13 units despite the imported data being in the range of 0.02 to 0.05 units. The right-mouse-button menu can be used to change the y-axis range to 0.02 to 0.05 units. When this is done, the imported data show as points on the plot and all looks good until the [Fit] button is selected wherein the imported data jumps out of the plotted area.

The selected Equation plots with a positive slope. Unfortunately a line through the imported data points indicates a negative slope. The slope of the plotted Equation line does not change to a negative value to fit the imported data. R2 displays as zero.

No amount of clearing data, resetting, changing Equations, or anything else changes the bottom line, which is a lot of effort for nothing accomplished. Please provide any information that can solve these frustrating problems. Thanks.

Harry will be back in his office 3 weeks from now. He will get back to you then.

Can you provide the data you were trying to fit as well as the equation type/number you were using? I understand that the initialization of the fitting process needs improvment but this is a non-trivial task.

Note that the fit is not a least square fit, but a http://en.wikipedia.org/wiki/Levenberg% ... _algorithm type. As such you will encounter differences with other sources.

Note that doing a fit always resets the graph settings, as this may be needed to visualize the new plot. I can only prevent this from happening if I would make a checkbox to keep the settings during the fit, however, typically this is not what most users would want to happen, or?

I am using PCDmanager v6.96 (2100/6)

I have emailed the file "Compound W surface tension (K, N%m) 1.1."

Surface Tension Data Fitting
Problem: No Plot for Eqn 106

Seems to be a different problem from before. The number of <Table> points seems to read in the 3 data pairs (after the 2nd attempt).

Please continue to work on PCDmanager.

The blank screen for the plot should now not appear anymore.
Further note that the fit capability will be improved in v7.00
Harry