The project Tutorial 1 can be very useful as a starting point
to make different types of function fits. The main page is illustrated in fig. 7.
The page has three main regions: header, body, and footer (I will not spend time with the footer).
- The header presents on the right side the links that
allow the user to change the fitting modes(Basic, the
default, Advanced, and Expert), to Upload
the contents of a previous fit that was saved locally in you
computer, to return to the MyFits page, or to
Logout. In addition the user can list the different fits
available in the project area, Recover the chosen one, or
Download it and save it in you personal computer. On the
left side the user has the possibility to save the current fit and
choose the project area name and the name of the current fit. The
date and time will be added to the name of the fit so that you will
be able to go back in history.
- The body has three main regions that actually
correspond to the three steps necessary to perform a
function fit to a set of experimental data: 1Data, 2 - Plot Parameters, and 3- Function and Parameters.
- Data has two text boxes. The first has by default a few
comment lines that start with ``#'' and a few lines with numbers
arranged in three columns and correspond the values of the variables
, , , where is the error estimate of
. The second box has a few lines that start by ``#'' by default
and correspond to examples of operations which you can perform with
the data in the Data Box. I think it is self explainatory but
you should try it and contact me if you have problems with
it. Calculate does what it means applies the calculation
rules to the data.
- Plot Parameters allows for the set the plot details and
I think it is self explaintory. One suggest you to check the grace
doc file on how to write subscripts, superscripts, etc..
- The Function and Parameters part is the most
interesting one. NUsers will see it like in
fig. 7. PUsers will see it like in
fig. 8. The difference is the option to call the
AuxCode Editor and the Additional C code box.
Depending on the Fitting mode the contents of this area might
change. You might try to change to Advanced mode and
Recover the fit Advanced-1.
Once you defined the variables name, declare them, write your C code
to calculate the value of the dependent variable you have to
Compile the function. If you get back the string
Compiled without errors everything is OK and you should see
a table below where you will identify the fitting parameters that you
defined in your function. There is a compilation log file where you
can check what is wrong with your function. This table has buttons to
fix or free each parameter, and three columns with
boxes where: Value can receive the starting value in the
numerical fit and will contain the output result of your fit,
Min, and Max allow you to set the lower and upper
limits in the parameters space where the fitting program will have to
try to find the best fit. A last column Error will present
you the error estimate of each fitted parameter.