R help - Mar 2010 - vcov.nlminb

Hello all,
I am trying to get the variance-covariance (VCOV) matrix of the
parameter estimates produced from the nlminb minimizing function, using
vcov.nlminb, but it seems to have been expunged from the MASS library.
The hessian from nlminb is also producing NaNs, although the estimates
seems to be right, so I can't VCOV that way either.  I also tried using
the vcov function after minimizing the function with the nlm function
and that produced the following error:

Error in UseMethod("vcov") : 
  no applicable method for 'vcov' applied to an object of class
"list"

Any thoughts on this would be welcome.

Thanks,
Brian
Essentia Institute of Rural Health
Duluth, MN
55805


	[[alternative HTML version deleted]]

Hello all,
I am trying to get the variance-covariance (VCOV) matrix of the
parameter estimates produced from the nlminb minimizing function, using
vcov.nlminb, but it seems to have been expunged from the MASS library.
I also tried using the vcov function after minimizing the function with
the nlm function and that produced the following error:

Error in UseMethod("vcov") : 
  no applicable method for 'vcov' applied to an object of class
"list"

The hessian from nlm is also producing NaNs, although the estimates
seems to be right, so I can't get the VCOV that way either.  Any
potential solutions on this would be welcome.

Thanks,
Brian
Essentia Institute of Rural Health
Duluth, MN
55805


	[[alternative HTML version deleted]]