* Ada implementation of QR decomposition @ 1997-07-24 0:00 Jan Galkowski 1997-07-25 0:00 ` Mats Weber 1997-08-04 0:00 ` Gautier 0 siblings, 2 replies; 4+ messages in thread From: Jan Galkowski @ 1997-07-24 0:00 UTC (permalink / raw) I'm lookin' for a time-saver here: Does anyone have an Ada implementation (preferably generic, but I doubt I'm going to get that latitude of choice) for the QR decomposition of a real matrix? -- Jan Theodore Galkowski, developer, statistician, speaking only for myself, jan@digicomp.com jtgalkowski@worldnet.att.net Member, the American Statistical Association, the Union of Concerned Scientists. ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Ada implementation of QR decomposition 1997-07-24 0:00 Ada implementation of QR decomposition Jan Galkowski @ 1997-07-25 0:00 ` Mats Weber 1997-08-04 0:00 ` Gautier 1 sibling, 0 replies; 4+ messages in thread From: Mats Weber @ 1997-07-25 0:00 UTC (permalink / raw) I don't know what a QR decomposition is, but I have a generic component that does this: -- Decomposes A in a product of two matrices L and U such that L*U = A, -- where L is a lower triangular matrix with all diagonal -- coefficients equal to ONE and U is an upper triangular matrix. -- (L and U are stored in A with zero coefficients omitted) -- P is the permutation of the rows of A necessary to achieve the -- decomposition in the case of zero pivots, P_ODD is set to TRUE if P -- is an odd permutation and PERMUTED is set to FALSE if P is the -- identity permutation. It is not 100% suitable for numerical work (I used it for operations in finite fields) because it doesn't choose the pivot very effectively (it just makes sure it is non-zero), but that should be easy to change. Just tell me if it suits your needs and I'll post it. ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Ada implementation of QR decomposition 1997-07-24 0:00 Ada implementation of QR decomposition Jan Galkowski 1997-07-25 0:00 ` Mats Weber @ 1997-08-04 0:00 ` Gautier 1997-08-05 0:00 ` Ken Thomas 1 sibling, 1 reply; 4+ messages in thread From: Gautier @ 1997-08-04 0:00 UTC (permalink / raw) > I'm lookin' for a time-saver here: Does anyone have an Ada > implementation (preferably generic, but I doubt I'm going to get > that latitude of choice) for the QR decomposition of a real > matrix? According to the system you're using, you can interface with the optimised xGEQRF Lapack routine in Fortran. -- Gautier -------- Homepage: http://www.unine.ch/math/Personnel/Assistants/Gautier/Montmollin.html Software: http://www.unine.ch/math/Personnel/Assistants/Gautier/Gaut_FTP.htm ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Ada implementation of QR decomposition 1997-08-04 0:00 ` Gautier @ 1997-08-05 0:00 ` Ken Thomas 0 siblings, 0 replies; 4+ messages in thread From: Ken Thomas @ 1997-08-05 0:00 UTC (permalink / raw) Gautier wrote: > > > I'm lookin' for a time-saver here: Does anyone have an Ada > > implementation (preferably generic, but I doubt I'm going to get > > that latitude of choice) for the QR decomposition of a real > > matrix? > > According to the system you're using, you can interface with the > optimised xGEQRF Lapack routine in Fortran. > > -- > Gautier > > -------- > Homepage: http://www.unine.ch/math/Personnel/Assistants/Gautier/Montmollin.html > Software: http://www.unine.ch/math/Personnel/Assistants/Gautier/Gaut_FTP.htm I have an implementation of the QR algorithm in Ada. It is (my own) child package of generic_real_arrays from Drexel http://dflwww.ece.drexel.edu/research/ada I can supply the source. -- Dr K.S. Thomas Department of Electronics and Computer Science University of Southampton Highfield Southampton SO17 1BJ United Kingdom Telephone : (+44) 01703 593029 Fax : (+44) 01703 593903 email: kst@ecs.soton.ac.uk ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~1997-08-05 0:00 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 1997-07-24 0:00 Ada implementation of QR decomposition Jan Galkowski 1997-07-25 0:00 ` Mats Weber 1997-08-04 0:00 ` Gautier 1997-08-05 0:00 ` Ken Thomas
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