[ADMB Users] ADMB-RE fitting failure in 11 but not in 10.1
Tim Miller
timothy.j.miller at noaa.gov
Thu Dec 6 08:47:39 PST 2012
Dear Users,
During the fitting of a random effects model in version 11 (Windows 7,
MinGW GCC-4.5.2), I get a failure with error message:
Error in matrix inverse -- matrix singular in solve(dmatrix)
This occurs before a .par file is written. In 10.1 convergence is fine.
The error doesn't occur in 11 when I use the sparse hessian option
-shess and in that case I get the same result as 10.1 (with or without
-shess).
I think I have traced it to the solve function in ludcmp_solve.cpp just
by searching for the error text in all the source code files and I think
the error occurs when checking the determinant. In version 11 the
function appears to check whether exp(sum(log(fabs(determinant
components)))) == 0.0 whereas in 10.1 it checks product(determinant
components) == 0.0.
Assuming I have traced the source of the error correctly, why is the
newer determinant checking method better than that in 10.1? If it is
better, maybe there is a way to continue on rather than exiting on the
error?
I could provide the tpl/dat files, but fitting the model without -shess
is annoying because it takes a while to get to the error.
Tim
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