Andreas Aschbacher
> I have two columns in ascii-sheet :
> x-col y-col
> 1 34
> 2 45
> 3 44
> ... and so on /experiment in radioactive measurement /
>
> and the following program in a do-file:
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> capture program drop nlexample
> program nlexample
> version 8
> if "`1'" == "?" {
> global S_1 "a1 a2 a3 a4 a5 a6"
...
> I reached convergence and good values for a1,a2,...with
> "right"start-values
> above after long 'trying' ......
> my questions::
> 1.) which parameter is the typical Marquardt-Parameter ?
Pass.
> 2.) although in reference-book:what does query-call and what does
> calculation-call mean ?
Think of the query call as initialising the problem and
the calculation calls as doing the numerics and statistics.
> 3.)after calling the program above with >do name< and after
> getting my
> results I print: predict myvar
> then I have with the command :twoway line myvar x a passable
> graph-fit,is this the correct way ?
This plots predicted against predictor.
Given that curve,
. twoway mspline myvar x
might look better.
You might also want to add the data points, say by
. twoway mspline myvar x || scatter y x
Alternatively,
. ssc desc regplot
. ssc inst regplot
. <nl fit>
. regplot y
Nick
[email protected]
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