how to convert from and to QR compact format?

Post here if you have a question about LAPACK or ScaLAPACK algorithm or data format

how to convert from and to QR compact format?

Postby bravegag » Sun Mar 25, 2012 8:31 am

Hello,

Please note that I am new to LAPACK and fortran.

Can anyone please point me to documentation or functions on how to convert from explicit Q and R to compact LAPACK QR? I would like to make my explicit Q and R to the QR format produced by dgeqrf.

I think I know how to do the other way around, from the compact LAPACK QR format to Q is using dorgqr or dormqr and recovering the R would be using cblas_dtrsm multiplying by the identity, right?

I need this in the context of an iterative algorithm that mutates matrices in different ways and it is very relevant to efficiently update QR by columns and/or row modifications and this is not standard part of LAPACK and therefore the need I have to deal with the different representations.

Many thanks in advance,
Best regards,
Giovanni
bravegag
 
Posts: 12
Joined: Sat Mar 24, 2012 3:23 pm

Re: how to convert from and to QR compact format?

Postby admin » Tue May 01, 2012 6:49 pm

admin
Site Admin
 
Posts: 504
Joined: Wed Dec 08, 2004 7:07 pm


Return to Algorithm / Data

Who is online

Users browsing this forum: No registered users and 1 guest