[vsni.co.uk] Contact us
Author Message
Post new topic

  ASReml  ~  bivariate spatial analysis

Posted: Wed Feb 22, 2012 2:29 pm Reply with quote
Joined: 13 Aug 2008 Posts: 32

I would like to fit a bivariate spatial analysis with exponential covariance functions. I have succesfully got a univariate model working using mtrnv, but I'm not sure how to set up a bivariate model. In a previous post, in the context of an AR1 process Arthur has suggested something along the lines of ;

us(trait):mtrn(lat, long, phi=1)

However this fails with the error "ASReml failed to invert a spatially indexed correelation structure The data may have duplicate points or the correlations are too high."

In any case, I think that even if this could be made to work it would have the same phi for each trait whereas I would like separate phi's for each.

The bivariate model with separate phi's can be fitted in spBayes, but it does not allow me to have a cross-covariance function between the two traits with a seprate phi and this is critical to the analysis. Specifically I would like three correlation functions:

COR(y1_i, y_1j) = exp(-d/phi_1)
COR(y1_i, y_2j) = exp(-d/phi_12)
COR(y2_i, y_2j) = exp(-d/phi_2)

I was hoping that ASreml could be made to fit such a model.

Any indication of whether such a model would be possible would be great.


View user's profile Send private message

Display posts from previous:  

All times are GMT
Page 1 of 1
Post new topic

Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum