MODIFY EQUATIONS IN THE SIGMAPLOT FIT LIBRARY
One
method for creating a custom curve
fitting library is to modify examples
from the SigmaPlot Fit Library.
This
makes creating the automatic
initial parameter estimation equations
easier. To do this use the Add
Equation to Notebook feature
to fill the notebook with your
custom equations. Then delete the
worksheet and graph and save the
notebook as a regression library.
Place some data that is typical
for the specific application into
the worksheet and create a scatter
graph.
Find
an equation in the SigmaPlot Fit
Library that is similar to the
one you are entering. For example,
for the Peppas equation F = ktn
use the 2 Parameter equation in
the Power Equation Category y =
axb. Click Edit Code and Add As
to 'unlock' the curve fitting statements
and add the new curve fit to the
User-Defined section.
Modify
the equations, variable definitions
and add constraints, if necessary.
Modify the automatic parameter
estimation equations (or use
numerical starting parameter values).
For the Peppas equation no changes
to the automatic parameter estimation
equations are required. Click
Next repeatedly through the Regression
Wizard and check the Add Equation
to Notebook box. Then click Finish.
Make
sure that the curve fitting process
worked properly and that the equation
was added to your notebook. Repeat
these steps to add other equations
to the library. When you are finished
adding equations to your notebook
delete the graph and the data worksheet
from the section.
You
should now have a notebook with
one section containing regression
icons for each equation you added.
Right click on the regression icons
and use Edit Info to label them
with each equation name. Save
the notebook as a SigmaPlot Regression
Library. This procedure produced
the regression library Release.jfl. |
