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# R: st: error 506 (matrix not positive definite) when bootstrapping eigenvalue after one-way manova

 From "Carlo Lazzaro" To Subject R: st: error 506 (matrix not positive definite) when bootstrapping eigenvalue after one-way manova Date Tue, 14 Jun 2011 17:55:19 +0200

```Dear Sergiy,
thanks a lot for your reply and pointing out my mistake in copying and
pasting the code. Now it seems to work properly (apart from error 506)
Kindest Regards,
Carlo
------------------------code begins--------------------------------
manova price mpg=foreign
mat c =e(eigvals_m)'
svmat double c, name(eigen_m)
scalar sctr=trace(c)
by foreign, sort: sum price
sum price if foreign==0, meanonly
replace price=price-r(mean)+6384.682 if foreign==0
sum price if foreign==1, meanonly
replace price=price-r(mean)+6384.682 if foreign==1
by foreign, sort: sum  mpg
sum  mpg if foreign==0, meanonly
replace  mpg= mpg-r(mean)+24.77273 if foreign==0
sum  mpg if foreign==1, meanonly
replace  mpg= mpg-r(mean)+24.77273 if foreign==1
bootstrap trace(c), reps(10000) nodots strata(foreign) bca seed(12345):
manova price mpg=foreign
-------------------------code ends------------------------------------
-----Messaggio originale-----
Da: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Per conto di Sergiy Radyakin
Inviato: martedì 14 giugno 2011 16.51
A: statalist@hsphsun2.harvard.edu
Oggetto: Re: st: error 506 (matrix not positive definite) when bootstrapping
eigenvalue after one-way manova

Hello Carlo,

the code you posted breaks down sooner with the message:
. svmat double c, name(eigen_m)
r(111);

What is in matrix C?

On Tue, Jun 14, 2011 at 9:19 AM, Carlo Lazzaro <carlo.lazzaro@tin.it> wrote:
> Dear Statalisters,
> before bootstrapping eigenvalue after one-way manova using auto.dta and
> Stata 9.2/SE, I imposed the equality of the means in price and mpg for
both
> foreign and domestic cars.
> When I invoked bootstrap, error message r(506) related to model term
foreign
> appeared.
> Can anybody please give me some hint about the reason of this drawback and
> how to work it around?
> Kindest Regards,
> Carlo
> ------------code begins-----------------------
> manova price mpg=foreign
> svmat double c, name(eigen_m)
> scalar sctr=trace(c)
> by foreign, sort: sum price
> sum price if foreign==0, meanonly
> replace price=price-r(mean)+6384.682 if foreign==0
> sum price if foreign==1, meanonly
> replace price=price-r(mean)+6384.682 if foreign==1
> by foreign, sort: sum  mpg
> sum  mpg if foreign==0, meanonly
> replace  mpg= mpg-r(mean)+24.77273 if foreign==0
> sum  mpg if foreign==1, meanonly
> replace  mpg= mpg-r(mean)+24.77273 if foreign==1
> bootstrap trace(c), reps(10000) nodots strata(foreign) bca seed(12345) :
> manova price mpg=foreign
> failure for model term foreign
> an error occurred when bootstrap executed manova
> r(506);
> ------------code ends-----------------------
>
>
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```