User`s guide

Parametric Fitting
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The results include this warning message.
Fit computation did not converge:
Maximum number of function evaluations exceeded. Increasing
MaxFunEvals (in fit options) may allow for a better fit, or
the current equation may not be a good model for the data.
To improve the fit for this example, specify reasonable starting points for the
coefficients. Deducing the starting points is particularly easy for the current
model because the Gaussian coefficients have a straightforward interpretation
and the exponential background is well defined. Additionally, as the peak
amplitudes and widths cannot be negative, constrain a
1
, a
2
, c
1
, and c
2
to be
greater then zero.
To define starting values and constraints for unknown coefficients, use the Fit
Options GUI, which you open by clicking the
Fit options button. The starting
values and constraints are shown below.
Specify reasonable coefficient
starting values and constraints.