Re: [Rd] Understanding svd usage and its necessity in generalized inverse calculation

2013-01-02 Thread Matt Blackwell
Hi all, On Tue, Jan 1, 2013 at 6:01 PM, Thomas Lumley wrote: > Now, if most of the matrices you are trying to invert are actually > invertible (as I would hope), it may be quicker to use the Cholesky > approach will a fallback to the SVD for semidefinite matrices. That is, > something like > >

Re: [Rd] Understanding svd usage and its necessity in generalized inverse calculation

2013-01-01 Thread Thomas Lumley
On Thu, Dec 6, 2012 at 12:58 PM, Paul Johnson wrote: > Dear R-devel: > > I could use some advice about matrix calculations and steps that might > make for faster computation of generalized inverses. It appears in > some projects there is a bottleneck at the use of svd in calculation > of generali