Re: [Lapackpp-devel] Cholesky Decomposition A = D'D

[Christian S. <sti...@tu...>]

Jacob (Jack) Gryn schrieb:
> Is there any documentation on the following matrices:
> LaSymmBandMatDouble
> LaSymmBandFactDouble
> LaSpdMatDouble
> LaSpdFactDouble

Err... No. The *Fact* classes are mentioned in the "Lapack++ 1.0 User 
Guide", but that's about it.

> As it stands, I don't really see anything to convert from a symmetric
> LaGenMatDouble to a LaSymmBandMatDouble or vice versa.  

A general conversion doesn't make sense, does it? I guess you mean if 
and only if a general matrix happens to be a symmetric matrix, then you 
would like to be able to convert it to the LaSymmBandMatDouble? But 
"Band" also refers to a banded matrix, doesn't it? In that case, the 
internal storage structure is probably totally different anyways, so you 
have to make an element-wise copy. In theory some function for this 
could be added to Lapackpp, yes.

> Is it possible to re-implement DPOTRF and/or DPBTRF to work with
> LaGenMatDouble's?

There is dgetrf, and LUFactorizeIP from laslv.h is using it. Is this 
what you were looking for?

Christian