On Fri, 30 Apr 1999, Arthur Gilmour wrote:
> Both terms are variance components. The spl(time) component is
> dependent on the scaling of the design matrix used which is not uniquely
> defined. I.e. I could change the spl(time) component without changing
> the fit of the spline.
huh, this is hard to follow
>
> I expect there is a direct relationship of these components and the
> spline smoothing parameter but it may not be simple in the unequally replicated
> case. i.e. in the unreplicated case there is just a spline variance
> and a residual variance. In your case there is a spline variance,
> a lack-of-fit variance and a residual variance. Whether the traditional
> smoothing parameter is a simple function of these quantities I know not.
The presence of dev(time) is to smooth at the right strata. If dev(time)
is not in the model then the fit will be rougher, ie large spl(time)
component, because the variance component is being estimated relative
only to error. It is crucial that this component is included for
replicated data, as discussed in our paper. It is still playing the same
role except now with another error term, which is akin to
r\sigma^2_g + \sigma^2_e
>
> One key to establishing this relationship is that the Z matrix used in ASREML
> is calculated assuming the variate is on the scale min=1, max=KNOTS
> i.e. time goes from 1 to 20 in your example [though not necessarily
> equally spaced within the interval]
>
> I'll pass this on to Ari who may know the answer.
> Otherwise, it means working through the algebra.
unnecessary i feel
> > Respectfully,
> >
> > Peter M. Saama /
> > --
> > Asreml mailinglist archive: http://www.chiswick.anprod.csiro.au/lists/asreml
>
>
> <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
> Arthur Gilmour PhD mailto:Arthur.Gilmour@agric.nsw.gov.au
> Senior Research Scientist (Biometrics) fax: <61> 2 6391 3899
> NSW Agriculture <61> 2 6391 3922
> Orange Agricultural Institute telephone work: <61> 2 6391 3815
> Forest Rd, ORANGE, 2800, AUSTRALIA home: <61> 2 6362 0046
>
> ASREML is still free by anonymous ftp from pub/aar on ftp.res.bbsrc.ac.uk
> or point your web browser at ftp://ftp.res.bbsrc.ac.uk/pub/aar/
>
> To join the asreml discussion list, send the message
> subscribe
> mailto:asreml-request@chiswick.anprod.CSIRO.au
>
> To send messages to the list, mailto:asreml@chiswick.anprod.CSIRO.au
>
> Asreml mailinglist archive: http://www.chiswick.anprod.csiro.au/lists/asreml
>
> <> <> <> <> <> <> <>
> "The Holy Scriptures are able to make you wise for salvation
> through faith which is in Christ Jesus.
> All Scripture is given by inspiration of God, and is profitable for
> doctrine, for reproof, for correction, for instruction in righteousness,
> That the man of God may be complete,
> thoroughly equipped for every good work." II Timothy 3:15-17.
> <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
>
>
> --
> Asreml mailinglist archive: http://www.chiswick.anprod.csiro.au/lists/asreml
>
...............................................................................
Brian Cullis Tel: 02 6938 1855
NSW Agriculture Fax: 02 6938 1809
Wagga Agricultural Institute email: brian.cullis@agric.nsw.gov.au
Pine Gully Rd
WAGGA WAGGA NSW 2650
--
Asreml mailinglist archive: http://www.chiswick.anprod.csiro.au/lists/asreml