TESTING/LIN/sqrt01.f(3) | Library Functions Manual | TESTING/LIN/sqrt01.f(3) |
NAME
TESTING/LIN/sqrt01.f
SYNOPSIS
Functions/Subroutines
subroutine sqrt01 (m, n, a, af, q, r, lda, tau, work,
lwork, rwork, result)
SQRT01
Function/Subroutine Documentation
subroutine sqrt01 (integer m, integer n, real, dimension( lda, * ) a, real, dimension( lda, * ) af, real, dimension( lda, * ) q, real, dimension( lda, * ) r, integer lda, real, dimension( * ) tau, real, dimension( lwork ) work, integer lwork, real, dimension( * ) rwork, real, dimension( * ) result)
SQRT01
Purpose:
SQRT01 tests SGEQRF, which computes the QR factorization of an m-by-n matrix A, and partially tests SORGQR which forms the m-by-m orthogonal matrix Q. SQRT01 compares R with Q'*A, and checks that Q is orthogonal.
Parameters
M
M is INTEGER The number of rows of the matrix A. M >= 0.
N
N is INTEGER The number of columns of the matrix A. N >= 0.
A
A is REAL array, dimension (LDA,N) The m-by-n matrix A.
AF
AF is REAL array, dimension (LDA,N) Details of the QR factorization of A, as returned by SGEQRF. See SGEQRF for further details.
Q
Q is REAL array, dimension (LDA,M) The m-by-m orthogonal matrix Q.
R
R is REAL array, dimension (LDA,max(M,N))
LDA
LDA is INTEGER The leading dimension of the arrays A, AF, Q and R. LDA >= max(M,N).
TAU
TAU is REAL array, dimension (min(M,N)) The scalar factors of the elementary reflectors, as returned by SGEQRF.
WORK
WORK is REAL array, dimension (LWORK)
LWORK
LWORK is INTEGER The dimension of the array WORK.
RWORK
RWORK is REAL array, dimension (M)
RESULT
RESULT is REAL array, dimension (2) The test ratios: RESULT(1) = norm( R - Q'*A ) / ( M * norm(A) * EPS ) RESULT(2) = norm( I - Q'*Q ) / ( M * EPS )
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 124 of file sqrt01.f.
Author
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