TESTING/EIG/dgqrts.f(3) | Library Functions Manual | TESTING/EIG/dgqrts.f(3) |
NAME
TESTING/EIG/dgqrts.f
SYNOPSIS
Functions/Subroutines
subroutine dgqrts (n, m, p, a, af, q, r, lda, taua, b, bf,
z, t, bwk, ldb, taub, work, lwork, rwork, result)
DGQRTS
Function/Subroutine Documentation
subroutine dgqrts (integer n, integer m, integer p, double precision, dimension( lda, * ) a, double precision, dimension( lda, * ) af, double precision, dimension( lda, * ) q, double precision, dimension( lda, * ) r, integer lda, double precision, dimension( * ) taua, double precision, dimension( ldb, * ) b, double precision, dimension( ldb, * ) bf, double precision, dimension( ldb, * ) z, double precision, dimension( ldb, * ) t, double precision, dimension( ldb, * ) bwk, integer ldb, double precision, dimension( * ) taub, double precision, dimension( lwork ) work, integer lwork, double precision, dimension( * ) rwork, double precision, dimension( 4 ) result)
DGQRTS
Purpose:
DGQRTS tests DGGQRF, which computes the GQR factorization of an N-by-M matrix A and a N-by-P matrix B: A = Q*R and B = Q*T*Z.
Parameters
N
N is INTEGER The number of rows of the matrices A and B. N >= 0.
M
M is INTEGER The number of columns of the matrix A. M >= 0.
P
P is INTEGER The number of columns of the matrix B. P >= 0.
A
A is DOUBLE PRECISION array, dimension (LDA,M) The N-by-M matrix A.
AF
AF is DOUBLE PRECISION array, dimension (LDA,N) Details of the GQR factorization of A and B, as returned by DGGQRF, see SGGQRF for further details.
Q
Q is DOUBLE PRECISION array, dimension (LDA,N) The M-by-M orthogonal matrix Q.
R
R is DOUBLE PRECISION array, dimension (LDA,MAX(M,N))
LDA
LDA is INTEGER The leading dimension of the arrays A, AF, R and Q. LDA >= max(M,N).
TAUA
TAUA is DOUBLE PRECISION array, dimension (min(M,N)) The scalar factors of the elementary reflectors, as returned by DGGQRF.
B
B is DOUBLE PRECISION array, dimension (LDB,P) On entry, the N-by-P matrix A.
BF
BF is DOUBLE PRECISION array, dimension (LDB,N) Details of the GQR factorization of A and B, as returned by DGGQRF, see SGGQRF for further details.
Z
Z is DOUBLE PRECISION array, dimension (LDB,P) The P-by-P orthogonal matrix Z.
T
T is DOUBLE PRECISION array, dimension (LDB,max(P,N))
BWK
BWK is DOUBLE PRECISION array, dimension (LDB,N)
LDB
LDB is INTEGER The leading dimension of the arrays B, BF, Z and T. LDB >= max(P,N).
TAUB
TAUB is DOUBLE PRECISION array, dimension (min(P,N)) The scalar factors of the elementary reflectors, as returned by DGGRQF.
WORK
WORK is DOUBLE PRECISION array, dimension (LWORK)
LWORK
LWORK is INTEGER The dimension of the array WORK, LWORK >= max(N,M,P)**2.
RWORK
RWORK is DOUBLE PRECISION array, dimension (max(N,M,P))
RESULT
RESULT is DOUBLE PRECISION array, dimension (4) The test ratios: RESULT(1) = norm( R - Q'*A ) / ( MAX(M,N)*norm(A)*ULP) RESULT(2) = norm( T*Z - Q'*B ) / (MAX(P,N)*norm(B)*ULP) RESULT(3) = norm( I - Q'*Q ) / ( M*ULP ) RESULT(4) = norm( I - Z'*Z ) / ( P*ULP )
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 174 of file dgqrts.f.
Author
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