From: Mats Weber <Mats.Weber@elca-matrix.ch>
Subject: Re: Ada implementation of QR decomposition
Date: 1997/07/25
Date: 1997-07-25T00:00:00+00:00 [thread overview]
Message-ID: <33D88188.F6871789@elca-matrix.ch> (raw)
In-Reply-To: 33D7607A.52BFA1D7@digicomp.com
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.
next prev parent reply other threads:[~1997-07-25 0:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
1997-07-24 0:00 Ada implementation of QR decomposition Jan Galkowski
1997-07-25 0:00 ` Mats Weber [this message]
1997-08-04 0:00 ` Gautier
1997-08-05 0:00 ` Ken Thomas
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