# st: LevenbergMarquardt/summary

 From "Andreas Aschbacher" <[email protected]> To [email protected] 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)
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 Gau�-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 Gau�-curves to be fitted,it is no problem to find
values
in Stata.but if I have to find three Gau�-curves,I mean to come from 1) to
2) for
example

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

2)
A1	11509.05
�1	4.403567
delta1	0.3050716
A2	1305.195
�2	4.18422
delta2	1.100233
A3	21540.19
�3	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.
andreas aschbacher

--
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```