TESTING/LIN/zlqt02.f(3)
๐ TESTING/LIN/zlqt02.f(3) ๐
Library Functions Manual, but make it bestie-friendly. This is the page for TESTING/LIN/zlqt02.f, and yes, it's giving serious LAPACK test-routine energy. ๐
โจ NAME โจ
TESTING/LIN/zlqt02.f โ that's the name, no cap. ๐ซถ
๐ธ SYNOPSIS ๐ธ
Functions/Subroutines
subroutine zlqt02 (m, n, k, a, af, q, l, lda, tau, work, lwork, rwork,
result)
ZLQT02
๐ Function/Subroutine Documentation ๐
subroutine zlqt02 (integer m, integer n, integer k, complex*16, dimension(
lda, * ) a, complex*16, dimension( lda, * ) af, complex*16, dimension(
lda, * ) q, complex*16, dimension( lda, * ) l, integer lda, complex*16,
dimension( * ) tau, complex*16, dimension( lwork ) work, integer lwork,
double precision, dimension( * ) rwork, double precision, dimension( * )
result)
ZLQT02
๐ฏ Purpose
Okay so here's the whole vibe: ZLQT02 tests ZUNGLQ, which generates an m-by-n matrix Q with orthonormal rows that is defined as the product of k elementary reflectors. ๐
Given the LQ factorization of an m-by-n matrix A, ZLQT02 generates the orthogonal matrix Q defined by the factorization of the first k rows of A; it compares L(1:k,1:m) with A(1:k,1:n)*Q(1:m,1:n)', and checks that the rows of Q are orthonormal. That's the whole main-character job, periodt. ๐
๐งฎ Parameters
MโM is INTEGER. It's the number of rows of the matrix Q to be generated. Constraint:M >= 0.NโN is INTEGER. It's the number of columns of the matrix Q to be generated. Constraint:N >= M >= 0.KโK is INTEGER. It's the number of elementary reflectors whose product defines the matrix Q. Constraint:M >= K >= 0.AโA is COMPLEX*16 array, dimension (LDA,N). This is the m-by-n matrix A which was factorized byZLQT01.AFโAF is COMPLEX*16 array, dimension (LDA,N). It holds details of the LQ factorization of A, as returned byZGELQF. SeeZGELQFfor further details.QโQ is COMPLEX*16 array, dimension (LDA,N). That's the whole description, bestie. Short and iconic.LโL is COMPLEX*16 array, dimension (LDA,M). Also short and iconic.LDAโLDA is INTEGER. It's the leading dimension of the arrays A, AF, Q and L. Constraint:LDA >= N.TAUโTAU is COMPLEX*16 array, dimension (M). These are the scalar factors of the elementary reflectors corresponding to the LQ factorization in AF.WORKโWORK is COMPLEX*16 array, dimension (LWORK). Werk, literally.LWORKโLWORK is INTEGER. It's the dimension of the array WORK.RWORKโRWORK is DOUBLE PRECISION array, dimension (M). Yes, real ones only. ๐RESULTโRESULT is DOUBLE PRECISION array, dimension (2). These are the test ratios:RESULT(1) = norm( L - A*Q' ) / ( N * norm(A) * EPS )andRESULT(2) = norm( I - Q*Q' ) / ( N * EPS ).
๐ Author
Shoutout to the author squad:
- Univ. of Tennessee
- Univ. of California Berkeley
- Univ. of Colorado Denver
- NAG Ltd.
Definition at line 133 of file zlqt02.f.
๐ค Author
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๐ฆ where this page comes from
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