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st: LevenbergMarquardt/summary


From   "Andreas Aschbacher" <aa_surf@gmx.at>
To   statalist@hsphsun2.harvard.edu
Subject   st: LevenbergMarquardt/summary
Date   Tue, 9 Mar 2004 11:07:46 +0100 (MET)

Dear fellows !
In austrian centre of physics we use Stata to do
LevenbergMarquardt(nl-coomand)
please look at my posting from january 20th with  heading:LevenbergMarquardt
short summary :the number of persons who is exposed to a little 
dosis-interval /about 0.01 mSv/ yields in sum a curve which is mostly
composed of 
two sometimes three humps.above each dosis-interval /about 0.01 mSv/there is
the number 
of persons as function. with Stata it was possible to show that in 397
cases we have the sum of Gauß-distributions.the results are very useful.
because of lv-command we can talk here about skewness of our curves.
median-test is also used very often.we decided to take Stata to use for our
work becaue it is so easy to split in subgroups and make tests after.
                                -

My question: if I have two Gauß-curves to be fitted,it is no problem to find
values
in Stata.but if I have to find three Gauß-curves,I mean to come from 1) to
2) for
example

1)
Ai for i = 1,2.... means amplitude
A1	12209.2
µ1	4.382678
delta1	0.3097696
A2	21683.69
µ2	4.200002
delta2	0.550282

2)
A1	11509.05
µ1	4.403567
delta1	0.3050716
A2	1305.195
µ2	4.18422
delta2	1.100233
A3	21540.19
µ3	4.198081
delta3	0.5104234

I need long time to try.with another famous statistical software I have
possibility to make 
constraints and it takes no long time.
I "fear the worst" that someone(my boss?) will ask me during my
presentation,if there are add-inns in Stata to use or user-written-programs that I have
this feature.
it is a pity that it is not possible for me to come to 2nd German Stata
User's meeting in April.
someone knows advice ?
andreas aschbacher

-- 
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